JP2002009004A - Method of manufacturing nitride semiconductor, nitride semiconductor device, method of manufacturing the same semiconductor light emitting device and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a nitride semiconductor formed through an ELOG method in crystallinity, to enable a resonator to have a large light confining coefficient, to form the resonator whose edge face is reduced in mirror loss, and to easily align a mask for forming a ridge. SOLUTION: A GaN seed layer 12 for ELOG is formed on a sapphire substrate 11 through the intermediary of a low-temperature GaN buffer layer, and stripe-shaped protuberant parts 12a extending in the plane direction of the substrate and separating from one another by a certain space are provided to the upper part of the GaN seed layer 12. In succession, a silicon nitride film 13 is formed on the bases and wall surfaces of recessed parts 12b each interposed between the protuberant parts 12a, and then a GaN selection growth layer 14 is formed above the seed layer 12, coming into contact with the protuberant parts 12a so as to form air gaps between its under surface and the bases of the recessed parts 12b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a nitride semiconductor used for a short wavelength semiconductor laser device or the like which is expected to be applied to the field of optical information processing and the like, a semiconductor device using the nitride semiconductor, and a semiconductor light emitting device. The present invention relates to an element and a method for manufacturing the element.

[0002]

2. Description of the Related Art In recent years, group III elements containing nitrogen (N)
A nitride semiconductor made of a group V compound is considered to be promising as a material for a short-wavelength light-emitting element because of its large energy gap. Of these, gallium nitride compound semiconductor _{(Al x Ga y In z N} (0 ≦ x, y, z ≦ 1, x + y
+ Z = 1)) is being actively researched and developed, and as a result, a blue or green light emitting diode (LE
D) The element has been put to practical use. Further, with the increase in the capacity of the optical disk device, a semiconductor laser device having an oscillation wavelength of about 400 nm is eagerly desired, and a semiconductor laser device using a gallium nitride-based semiconductor is reaching a practical level.

(First Conventional Example) Hereinafter, a gallium nitride based semiconductor laser device according to a first conventional example will be described with reference to the drawings.

FIG. 37 shows a sectional structure of a conventional gallium nitride based semiconductor laser device in which laser oscillation is achieved. As shown in FIG. 37, a conventional semiconductor laser device is sequentially formed on a substrate 301 made of sapphire by, for example, a metal organic chemical vapor deposition (MOVPE) method.
Buffer layer 302 made of gallium nitride (GaN), n
-Type contact layer 303 made of n-type GaN, n-type cladding layer 304 made of n-type aluminum gallium nitride (AlGaN), and n-type light guide layer 30 made of n-type GaN
5, different gallium nitride indium composition of the indium _{(Ga 1-x In x N} / Ga 1-y In y N ( where, 0 <y
<X <1), a multiple quantum well (MQW) active layer 306 laminated, and a p-type optical guide layer 30 composed of p-type GaN
7, a p-type cladding layer 308 made of p-type AlGaN, and a p-type contact layer 309 made of p-type GaN.

A ridge having a width of about 3 μm to 10 μm is formed on the p-type cladding layer 308 and the p-type contact layer 309. The stacked body including the MQW active layer 306 is etched so as to expose a part of the n-type contact layer 303, and the top and side surfaces of the etched stacked body are covered with the insulating film 310. Insulating film 3
A stripe-shaped opening is provided in the upper part of the p-type contact layer 309 in FIG. 10, and a p-side electrode 311 that makes ohmic contact with the p-type contact layer 309 through the opening is formed on the ridge of the insulating film 310. Have been.
An n-side electrode 312 that makes ohmic contact with the n-type contact layer 303 is provided on a portion of the n-type contact layer 303 exposed from the insulating film 310.

When the n-side electrode 312 of the semiconductor laser device thus formed is grounded and a predetermined voltage is applied to the p-side electrode 311, an optical gain is generated in the MQW active layer 306, and the oscillation wavelength becomes about 400 nm. Causes laser oscillation.

The oscillation wavelength of the laser beam depends on the MQW active layer 30.
6 changes depending on the composition or film thickness of Ga _1-x In _x N and Ga _1-y In _y N. At present, continuous oscillation at room temperature or higher is realized.

By adjusting the width or height of the ridge, laser oscillation in the fundamental mode in the horizontal mode (parallel to the substrate surface) is enabled. That is, by providing a difference in the light confinement coefficient between the fundamental transverse mode and the first or higher order mode, oscillation in the fundamental transverse mode is enabled.

The substrate 301 includes, in addition to sapphire, silicon carbide (SiC) or neodymium gallate (NdGa).
O ₃ : Neodymium gallate) or the like is used, but none of the materials can perform lattice matching with gallium nitride, and it is difficult to obtain coherent growth. As a result, there are many edge dislocations, screw dislocations, or mixed dislocations in which dissimilar dislocations are mixed. For example, when sapphire is used for a substrate, about 1 × 10 ⁹
The presence of cm ⁻² dislocations causes a decrease in the reliability of the semiconductor laser device.

Therefore, as a method for reducing the dislocation density,
Selective lateral growth (epitaxial latera)
lovergrowth (ELOG) method has been proposed. This is because in a semiconductor crystal with large lattice mismatch,
This is effective as a method for reducing threading dislocations.

(Second Conventional Example) FIG. 38 schematically shows the distribution of crystal dislocations in a semiconductor layer made of gallium nitride formed by ELOG.

An outline of the ELOG method will be described with reference to FIG. 38. First, a seed layer 402 made of GaN is formed on a substrate 401 made of sapphire by MOVPE or the like.
Grow.

Next, after depositing a dielectric film made of silicon oxide or the like by a chemical vapor deposition (CVD) method or the like, a predetermined period of time is obtained from the deposited dielectric film by a photolithography method and an etching method. A mask film 403 having a stripe-shaped opening pattern is formed.

Next, a semiconductor layer 404 made of GaN is formed on the mask film 403 by selective growth using a portion of the seed layer 402 exposed from the mask film 303 as a seed crystal by MOVPE or halide vapor phase epitaxy (HVPE). Grow.

At this time, the region above the opening of the mask film 403 in the semiconductor layer 404 has a dislocation density of about 1 × 1
Although a high dislocation density region 404a of about ⁰⁹ cm ^-2 is obtained, a low dislocation density region 404b having a dislocation density of about 1 x 10 ⁷ cm ^-2 is obtained in a region laterally grown on the mask film 403.

FIG. 39 shows a sectional structure of a semiconductor laser device in which an active region, that is, a ridge portion serving as a current injection region is formed above the low dislocation density region 404b. 39, the same components as those shown in FIGS. 37 and 38 are denoted by the same reference numerals.

As described above, by providing the current injection region above the low dislocation density region 404b in the MQW active layer 306, the reliability of the laser device can be improved.

[0018]

As a result of various studies, the inventors of the present invention have found that the semiconductor laser devices according to the first and second prior arts described above have various characteristics as described below. Have found a problem.

First, problems with the nitride semiconductor growth method by the ELOG method according to the second conventional example will be described.

FIGS. 40A to 40D show the semiconductor layer 4.
This schematically shows a state in which a gallium nitride polycrystal 405 is deposited on the mask film 403 during growth of the semiconductor layer 04 and the crystallinity of the semiconductor layer 404 is degraded.

Specifically, as shown in FIG.
First, the mask film 4 having an opening on the upper surface of the seed layer 402
Next, as shown in FIG. 40 (b), a plurality of semiconductor layers 404 are formed by using a region of the seed layer 402 exposed from each opening of the mask film 403 as a seed crystal.
Grow respectively. At this time, the mask film 403 is made of a dielectric, and a plurality of polycrystals 405 that are not crystallized on the dielectric may be deposited.

Next, as shown in FIGS. 40 (c) and 40 (d), in the state where the polycrystalline body 405 is deposited, the plurality of semiconductor layers 404 are integrated and grown until the surface is flattened. By continuing, a region 404c having poor crystallinity is formed on the polycrystalline body 405.

The inventors of the present application have proposed that the region 4 having poor crystallinity
It has been found that even if a current injection region is formed above the laser element 04, a laser element having good characteristics can never be obtained.

Second, in the semiconductor laser devices according to the first and second conventional examples, it is difficult to increase the light confinement coefficient in the direction perpendicular to the substrate surface of the active layer. Have found.

FIG. 41 shows the relationship between the refractive index distribution in the direction perpendicular to the substrate surface of the MQW active layer 306 and the light intensity distribution at the cavity facet in the semiconductor laser device according to the first conventional example. Is shown. Part of the generated light confined in the MQW active layer 306 leaks to the substrate 301,
It can be seen that a standing wave is generated in the n-type contact layer 303. As described above, the MQW active layer 306 is
If the generated light leaks to 1 largely, the light confinement rate to the MQW active layer 306 decreases, and the oscillation threshold of the laser light increases.

FIG. 42 shows a far-field image of the laser device according to the first conventional example. Here, the horizontal axis represents the deviation of the emitted light in the horizontal direction (substrate surface direction) from the normal direction of the cavity end face, and the vertical axis represents the light intensity of the emitted light. If there is much leakage of generated light to the substrate 301 side as in the first conventional example, it is also difficult to obtain a unimodal far-field image. This is the same in the semiconductor laser device according to the second conventional example.

Third, the semiconductor laser device according to the first conventional example includes a plurality of laser devices formed in a wafer state.
For example, when individual laser chips are formed by cleavage, there is a problem that a flat surface cannot be obtained at the end face of the resonator because the crystal plane of the substrate made of sapphire and the nitride semiconductor layer are different. That is, as shown in FIG. 43, the sapphire forming the substrate 301 has a plane orientation of (1).
Since the cleavage of the so-called M plane of the (-100) plane is easy, the M plane of sapphire is usually used as the cleavage plane.

However, since the M plane of a nitride semiconductor, for example, gallium nitride, is shifted by 30 degrees within the plane from the M plane of sapphire, the M plane of sapphire and (1)
The 1-20) plane, the so-called A plane, coincides. For this reason, when the substrate 301 is cleaved, a cleaved surface in which the cleaved surface is shifted from the substrate 301 by 30 degrees appears in the buffer layer 302 and the stacked body thereon as an uneven surface with a step of several hundred nm.

When the end face of the resonator has such an uneven surface,
Since the mirror loss of the laser beam due to the end face of the resonator increases, the operating current of the semiconductor laser element increases, and the reliability decreases. Furthermore, since the concave and convex portions of the resonator end face are randomly generated, it becomes difficult to form a resonator end face having a predetermined reflectance with good reproducibility, and the yield is reduced. Note that a similar problem occurs even when a dry etching method is used instead of the cleavage method for forming the resonator. In the specification of the present application, a negative sign of the plane orientation is used.
-"Represents the inversion of one exponent following the minus sign.

On the other hand, in the case of the semiconductor laser device according to the second conventional example, the stripe-shaped opening of the mask film 403 for selective growth is formed so as to be parallel to the M axis of the semiconductor layer 404. This is because the rate of lateral growth in the A-axis direction is much faster than in other directions, and selective growth can be performed efficiently in a short time. Therefore, the low dislocation density region 4
Since 04b is parallel to the M axis, the cavity facet of the laser element formed on the low dislocation density region necessarily becomes the M plane. As a result, it is necessary to cleave the surface A of the substrate 401. As described above, sapphire is easily cleaved on the M-plane, but not so easy on the A-plane. Therefore, there is a problem that the yield of the semiconductor laser device is greatly reduced.

Fourth, in the ELOG method, the angle (tilt) between the C axis of the seed layer 402 and the C axis of the semiconductor layer 404 selectively grown thereon is about 0.1 to 1 degree. It is known.

On the other hand, the low dislocation density region 404b obtained by the ELOG method is again used as a seed crystal,
04a with another mask film for selective growth, and
By performing LOG growth, a nitride semiconductor crystal including only the low dislocation density region 404b can be obtained. This makes it possible to form a resonator having an A-plane end face on a crystal consisting only of the low dislocation density region 404b, and it is possible to greatly improve the yield due to cleavage.

However, when a resonator is formed in the A-axis direction, the distance between the seed layer 402 and the selectively grown layer thereon is
Since the tilt of the C axis described above exists, the waveguide has a zigzag shape in the C axis direction. The zigzag waveguide has a problem that a waveguide loss occurs and an operating current of the laser element increases. In the case of forming a vertical cavity surface emitting laser element array in which a plurality of resonators are provided in directions perpendicular to the substrate surface, each laser beam is emitted from the array resonator. There is a problem that the directions do not match.

Fifth, in the semiconductor laser device according to the second conventional example, the width between the low dislocation density regions 404b is about 5 μm.
m, which is extremely small, and it is necessary to align the photomask of the ridge portion having a width of about 3 μm so as not to deviate from the low dislocation density region 404b. as a result,
Since high precision is required for alignment in the photolithography process, there is a problem that the throughput and the yield of the photolithography process are reduced, and the production efficiency cannot be improved.

The present invention has been made in view of the various problems described above, and a first object of the present invention is to improve crystallinity by the ELOG method, and to increase the confinement coefficient of light in a resonator. A second object is to form a resonator end face having a small mirror loss, a fourth object is to be able to form a resonator having a small waveguide loss, and a ridge portion is provided. A fifth object is to facilitate alignment of a mask for formation. Accordingly, the present invention has an excellent effect particularly when applied to a laser element for an optical disk device.

[0036]

The first method of manufacturing a nitride semiconductor according to the present invention In order to achieve the above object, according to achieve the first object, on the _{substrate, Al u Ga v In w N} ( where, u, v , W is 0
≦ u, v, w ≦ 1, u + v + w = 1. A) forming a first nitride semiconductor layer comprising: forming a plurality of protrusions extending above the first nitride semiconductor layer at intervals from each other in a substrate surface direction; Forming a mask film that covers the bottom surface of the concave portion sandwiched between the convex portions, and forming a seed crystal on the first nitride semiconductor layer by exposing the C-plane as the top surface of each convex portion exposed from the mask film. As Al
_x Ga _y In _z N (where, x, y, z are, 0 ≦ x, y,
z ≦ 1, x + y + z = 1. A) growing a second nitride semiconductor layer comprising:

According to the first method for manufacturing a nitride semiconductor,
A plurality of protrusions are formed on the upper surface of the first nitride semiconductor layer, and the bottom surface sandwiched between the formed protrusions is covered with a mask film. Therefore, the second nitride semiconductor layer is formed of the first nitride semiconductor layer. Only the C-plane appearing on the top surface of the convex portion grows as a seed crystal.
As a result, even if the polycrystalline body of the second nitride semiconductor layer is deposited on the mask film, the second nitride semiconductor layer is not formed because the mask film is provided on the bottom surface between the projections. When growing in the direction parallel to the substrate surface (lateral growth), it grows above the polycrystal, so that the growth is not hindered by the polycrystal and the crystallinity of the second nitride semiconductor layer is good. Become.

Method for manufacturing the second nitride semiconductor according to the present invention
The method achieves the first object and forms Al on a substrate._u Ga
_v In_w N (where u, v, w are 0 ≦ u, v, w ≦
1, u + v + w = 1. ) Comprising a first nitride half
A step of forming a conductor layer and an upper part of the first nitride semiconductor layer
A plurality of protrusions extending at intervals from each other in the substrate surface direction
And the step of forming the
Cover the bottom surface of the concave portion and at least a part of the wall surface.
Forming a mask film, and forming a mask film on the first nitride semiconductor layer.
Next, the region exposed from the mask film in each convex portion is set as a seed crystal.
As Al_x Ga _y In_z N (where x, y, and z are
0 ≦ x, y, z ≦ 1, x + y + z = 1. )
Growing a second nitride semiconductor layer.
You.

According to the second method for manufacturing a nitride semiconductor,
When the second nitride semiconductor layer grows in a direction parallel to the substrate surface, even if a polycrystalline substance of the second nitride semiconductor layer is deposited on the mask film, the mask film is formed between the convex portions. Since the second nitride semiconductor layer is provided on at least a part of the bottom surface and the wall surface of the second nitride semiconductor layer, the second nitride semiconductor layer grows above the polycrystalline body. Has good crystallinity.

A first method of manufacturing a nitride semiconductor device according to the present invention achieves the first object, a step of forming a first nitride semiconductor layer on a substrate, and a step of forming a first nitride semiconductor. Forming a plurality of grooves extending at intervals from each other in the substrate surface direction on the layer, forming a mask film covering a bottom surface of the grooves, forming a plurality of grooves on the upper surface of the first nitride semiconductor layer; A second nitride semiconductor layer and a third nitride semiconductor layer having an energy gap smaller than that of the second nitride semiconductor layer from the substrate side, with the C-plane exposed from the mask film as a seed crystal during the process.
Growing a stacked body so as to include an active layer made of a nitride semiconductor layer of (a) and a fourth nitride semiconductor layer having an energy gap larger than that of the active layer; Forming a current constriction portion for selectively injecting a current.

According to the first method for manufacturing a nitride semiconductor device, since the stacked body including the active layer is formed by the first method for manufacturing a nitride semiconductor of the present invention, the active layer and the active layer are sandwiched from above and below. The crystallinity of each of the nitride semiconductor layers is excellent. For this reason, the reliability as a semiconductor element can be significantly improved.

A second method for manufacturing a nitride semiconductor device according to the present invention achieves the first object, a step of forming a first nitride semiconductor layer on a substrate, and a method of forming a first nitride semiconductor. Forming a plurality of grooves extending above the layer at a distance from each other in the direction of the substrate surface, forming a mask film covering a bottom surface of the grooves and at least a part of the wall surface thereof, A region exposed from the mask film between the trenches on the semiconductor layer is used as a seed crystal to form, from the substrate side, a second nitride semiconductor layer and a second nitride semiconductor layer having an energy gap smaller than that of the second nitride semiconductor layer. Growing a stacked body so as to include an active layer made of a nitride semiconductor layer of No. 3 and a fourth nitride semiconductor layer having an energy gap larger than that of the active layer; Current constriction to selectively inject carriers And a step of forming.

According to the second method for manufacturing a nitride semiconductor device, since the laminated body including the active layer is formed by the second method for manufacturing a nitride semiconductor of the present invention, the active layer and the active layer are sandwiched from above and below. The crystallinity of each of the nitride semiconductor layers is excellent. For this reason, the reliability as a semiconductor element can be significantly improved.

A third method for manufacturing a nitride semiconductor according to the present invention achieves the first object and includes a step of forming a plurality of projections extending parallel to each other in a substrate surface direction on an upper portion of a substrate. , the top surface of each convex section on the substrate, Al _x Ga _y in _z N
(However, x, y, z are 0 ≦ x, y, z ≦ 1, x + y +
z = 1. A) selectively growing a nitride semiconductor layer comprising

According to the third method for manufacturing a nitride semiconductor,
The same effects as those of the first method for manufacturing a nitride semiconductor according to the present invention can be obtained, and since a stripe-shaped projection is provided on the substrate itself, a semiconductor layer for a seed crystal is not required. In addition, when a nitride semiconductor is not used for a substrate, it is not necessary to provide a mask film for selective growth, and the semiconductor manufacturing process can be greatly simplified.

A third method of manufacturing a nitride semiconductor device according to the present invention achieves the first object and forms a plurality of grooves extending at intervals in a substrate surface direction on an upper surface of a substrate. A first nitride semiconductor layer on a region between the grooves on the upper surface of the substrate, selectively from the substrate side;
A stacked body including an active layer made of a second nitride semiconductor layer having an energy gap smaller than the first nitride semiconductor layer and a third nitride semiconductor layer having an energy gap larger than the active layer And a step of forming a current confinement portion for selectively injecting carriers into the active layer on the laminate.

According to the third method for manufacturing a nitride semiconductor device, since the stacked body including the active layer is formed by the third method for manufacturing a nitride semiconductor of the present invention, the active layer and the active layer are sandwiched from above and below. Since the crystallinity of each nitride semiconductor layer is excellent and the manufacturing process can be greatly simplified,
Productivity can be improved.

The first nitride semiconductor device according to the present invention comprises:
The second object is achieved by sequentially forming on the substrate,
An active layer comprising a second nitride semiconductor layer having a higher light refractive index than the first nitride semiconductor layer, and a third nitride having a lower light refractive index than the active layer A laminate including a semiconductor layer; and a current constriction formed on the laminate and selectively injecting carriers into the active layer. A void is formed in a region between them.

According to the first nitride semiconductor device, a gap portion having a smaller refractive index of light than the semiconductor is provided in a region between the active layer and the substrate below the current confining portion in the active layer. Therefore, the generated light generated in the active layer hardly leaks to the substrate side, so that the value of the confinement coefficient of the generated light in the active layer can be increased.

The second nitride semiconductor device according to the present invention comprises:
A first nitride semiconductor layer formed on a substrate, the first nitride semiconductor layer having a plurality of protrusions extending in a substrate surface direction at intervals from each other on the substrate to achieve the second object; A second upper surface is formed so that the lower surface is in contact with the top surface of each projection.
A third nitride semiconductor layer formed on the third nitride semiconductor layer and the second nitride semiconductor layer, and a fourth nitride semiconductor having a higher refractive index of light than the third nitride semiconductor layer And a fifth nitride semiconductor layer having a lower refractive index of light than the active layer. The second nitride semiconductor layer is formed of a third nitride semiconductor layer. It has a refractive index smaller than or equal to the refractive index of light.

According to the second nitride semiconductor device, the second nitride semiconductor layer grows with the top surface of the projection of the first nitride semiconductor layer having the stripe-shaped projection on top as a seed crystal. Therefore, the lower part of the second nitride semiconductor layer and the first
A void is formed in a region between the convex portions of the nitride semiconductor layer. Further, since the second nitride semiconductor layer has a refractive index smaller than or equal to the refractive index of light of the third nitride semiconductor layer, it is preferable to provide a current confinement portion above a void in the stacked body. In addition, the value of the light confinement coefficient in the active layer surely increases.

A fourth method for manufacturing a nitride semiconductor device according to the present invention achieves the second object, a step of forming a first nitride semiconductor layer on a substrate, and a step of forming a first nitride semiconductor. Forming a plurality of grooves extending at intervals from each other in the substrate surface direction on the layer, forming a mask film covering a bottom surface of the grooves, forming a plurality of grooves on the upper surface of the first nitride semiconductor layer; A second nitride semiconductor layer, a third nitride semiconductor layer, and a refraction of light higher than that of the third nitride semiconductor layer from the substrate side, with the C-plane exposed from the mask film as a seed crystal. An active layer composed of a fourth nitride semiconductor layer having a high rate,
Growing the laminate so as to include a fifth nitride semiconductor layer having a lower refractive index of light than the active layer; and forming a current constriction on the laminate to selectively inject carriers into the active layer. Forming a stacked body, wherein the step of growing the stacked body includes the second step.
Growing the nitride semiconductor layer so that the refractive index of the light is smaller than or equal to the refractive index of the light of the third nitride semiconductor layer.

According to the fourth method for manufacturing a nitride semiconductor device, the second nitride semiconductor device of the present invention can be reliably formed.

A fifth method of manufacturing a nitride semiconductor device according to the present invention achieves the second object, a step of forming a first nitride semiconductor layer on a substrate, and a step of forming a first nitride semiconductor. Forming a plurality of grooves extending above the layer at a distance from each other in the direction of the substrate surface, forming a mask film covering a bottom surface of the grooves and at least a part of the wall surface thereof, A second nitride semiconductor layer, a third nitride semiconductor layer, a third nitride semiconductor layer, a third nitride semiconductor layer, and a third nitride layer. A stacked body is grown so as to include an active layer made of a fourth nitride semiconductor layer having a higher refractive index of light than the semiconductor layer and a fifth nitride semiconductor layer having a lower refractive index of light than the active layer. And a step of selectively injecting carriers into the active layer on the laminate. Forming a confined portion, wherein the step of growing the stacked body includes the step of forming the second nitride semiconductor layer such that a refractive index of light of the second nitride semiconductor layer is smaller than a refractive index of light of the third nitride semiconductor layer or Including the step of growing to be equivalent.

According to the fifth method for manufacturing a nitride semiconductor device, the second nitride semiconductor device of the present invention can be reliably formed.

A fourth method for manufacturing a nitride semiconductor according to the present invention achieves the third object, and forms Al _u Ga on a substrate.
_v In _w N (where u, v, w are 0 ≦ u, v, w ≦
1, u + v + w = 1. A) forming a first nitride semiconductor layer comprising: forming a plurality of protrusions extending above the first nitride semiconductor layer at intervals from each other in a substrate surface direction; Forming a mask film covering a bottom surface of the concave portion sandwiched between the convex portions;
On top of the nitride semiconductor layer, the C surface is a top surface of each convex portion exposed from the mask film as a seed crystal, Al _x Ga _y In _z
N (where x, y, and z are 0 ≦ x, y, z ≦ 1, x + y
+ Z = 1. A) growing a plurality of second nitride semiconductor layers, the step of forming a plurality of second nitride semiconductor layers comprises the steps of: The method includes the step of forming a side end surface parallel to a direction in which the convex portions extend each time the object semiconductor layer straddles a predetermined number of the convex portions among the plurality of convex portions.

According to the fourth method for manufacturing a nitride semiconductor,
Each of the second nitride semiconductor layers is placed on a side parallel to the direction in which the projections extend each time a predetermined number of the plurality of projections provided on the first nitride semiconductor layer are straddled. Since the end face is formed so as to be exposed, if the side end face is used as the resonator end face, the resonator end face is not affected by the cleavage face or the etching face, so that the mirror loss at the resonator end face can be reduced.

Fifth Method of Manufacturing Nitride Semiconductor According to the Present Invention
The method achieves the third object and forms Al on a substrate._u Ga
_v In_w N (where u, v, w are 0 ≦ u, v, w ≦
1, u + v + w = 1. ) Comprising a first nitride half
A step of forming a conductor layer and an upper part of the first nitride semiconductor layer
A plurality of protrusions extending at intervals from each other in the substrate surface direction
And the step of forming the
Cover the bottom surface of the concave portion and at least a part of the wall surface.
Forming a mask film, and forming a mask film on the first nitride semiconductor layer.
Next, the region exposed from the mask film in each convex portion is set as a seed crystal.
As Al_x Ga _y In_z N (where x, y, and z are
0 ≦ x, y, z ≦ 1, x + y + z = 1. )
Growing a plurality of second nitride semiconductor layers.
In addition, the step of forming a plurality of second nitride semiconductor layers includes:
Each second nitride semiconductor layer is composed of a plurality of second nitride semiconductor layers.
Each time a predetermined number of the convex portions are straddled, the convex portion extends.
Forming the side end surface parallel to the direction
including.

According to the fifth method for manufacturing a nitride semiconductor,
Each of the second nitride semiconductor layers is placed on a side parallel to the direction in which the projections extend each time a predetermined number of the plurality of projections provided on the first nitride semiconductor layer are straddled. Since the end face is formed so as to be exposed, if the side end face is used as the resonator end face, the resonator end face is not affected by the cleavage face or the etching face, so that the mirror loss at the resonator end face can be reduced.

A sixth method of manufacturing a nitride semiconductor device according to the present invention achieves the third object, a step of forming a first nitride semiconductor layer on a substrate, and a step of forming a first nitride semiconductor. Forming a plurality of grooves extending at intervals from each other in the substrate surface direction on the layer, forming a mask film covering a bottom surface of the grooves, forming a plurality of grooves on the upper surface of the first nitride semiconductor layer; A second nitride semiconductor layer and a third nitride each having a smaller energy gap than the second nitride semiconductor layer from the substrate side, with the C-plane exposed from the mask film as a seed crystal between the second nitride semiconductor layer and the second nitride semiconductor layer. Growing a plurality of stacked bodies so as to include an active layer made of a semiconductor layer and a fourth nitride semiconductor layer having a larger energy gap than the active layer;
Forming a current confinement portion for selectively injecting a carrier into the active layer on each of the stacked bodies, wherein the step of growing a plurality of stacked bodies includes: And a step of exposing a cavity end face formed of a current confinement portion every time a predetermined number of straddles the C-plane of the nitride semiconductor layer.

According to the sixth method for manufacturing a nitride semiconductor device, each laminated body including an active layer is formed by the fourth method for manufacturing a nitride semiconductor of the present invention, so that the cavity end face is cleaved. And the mirror surface is no longer affected by the etched surface, so that the mirror loss at the end face of the resonator can be reduced.

A seventh method for manufacturing a nitride semiconductor device according to the present invention achieves the third object, a step of forming a first nitride semiconductor layer on a substrate, and a method of manufacturing a first nitride semiconductor device. Forming a plurality of grooves extending above the layer at a distance from each other in the direction of the substrate surface, forming a mask film covering a bottom surface of the grooves and at least a part of the wall surface thereof, A region exposed from the mask film between the respective trenches on the semiconductor layer is used as a seed crystal, and from the substrate side, each has a second nitride semiconductor layer and an energy gap larger than that of the second nitride semiconductor layer. Growing a plurality of stacked bodies so as to include an active layer made of a third nitride semiconductor layer having a small thickness and a fourth nitride semiconductor layer having an energy gap larger than the active layer; Above, selective carrier for active layer Forming a plurality of stacked bodies, wherein each of the stacked bodies is formed in a region between adjacent trenches of the first nitride semiconductor layer. The method includes a step of exposing a cavity end face composed of a current confinement portion every time a predetermined number of straddles are performed.

According to the seventh method for manufacturing a nitride semiconductor device, each laminated body including an active layer is formed by the fifth method for manufacturing a nitride semiconductor of the present invention, so that the cavity end face is cleaved. And the mirror surface is no longer affected by the etched surface, so that the mirror loss at the end face of the resonator can be reduced.

A third nitride semiconductor device according to the present invention comprises:
Achieving the third and fourth objects, formed on a substrate,
A first nitride semiconductor layer having a plurality of protrusions extending in the direction of the substrate surface at an interval from each other on the upper portion, and forming a void on the first nitride semiconductor layer and between the side surfaces of the protrusions. A second nitride semiconductor layer formed so as to have a third nitride semiconductor layer formed on the second nitride semiconductor layer and including a stripe-shaped resonator into which carriers are confined and injected. And the resonator is provided such that the resonance direction of the generated light is substantially orthogonal to the direction in which the convex portion extends.

According to the third nitride semiconductor device, since the resonator is provided so that the resonance direction of the generated light is substantially orthogonal to the direction in which the convex portion extends, for example, the direction in which the convex portion extends is M
When the direction is the axial direction and the direction of resonance of the resonator is the A-axis direction, the end face of the resonator becomes the A-plane. Therefore, when sapphire is used for the substrate, the cleavage surface of the substrate becomes the M plane, the cleavage is facilitated, and the yield at the time of cleavage is improved. In this case, the resonator intersects with a plurality of projections serving as a seed crystal. However, since the first nitride semiconductor layer has a gap between the side surfaces of the projections, the first nitride semiconductor layer has a first nitride semiconductor layer. Since the tilt of the C-axis between the semiconductor layer and the second nitride semiconductor layer is suppressed, the waveguide loss is also reduced.

A fourth nitride semiconductor device according to the present invention comprises:
A first nitride semiconductor layer formed on the substrate and having a plurality of protrusions on the top and extending in the direction of the substrate surface at intervals from each other; and a side surface of each protrusion on the first nitride semiconductor layer. A second nitride semiconductor layer formed so as to have a gap therebetween, and a third nitride semiconductor layer formed on the second nitride semiconductor layer and including an active layer; The top surface of the convex portion of the nitride semiconductor layer is a C-plane, and the angle (tilt angle) between the C-axis of the first nitride semiconductor layer and the C-axis of the second nitride semiconductor layer is about 0. 0.05 degrees or less.

According to the fourth nitride semiconductor device, when the second nitride semiconductor layer is grown by lateral growth in which a gap is formed, the tilt angle is 0.05 degrees or less. Even when a waveguide is provided in the third semiconductor layer including the layer, the waveguide is prevented from forming a zigzag shape undulating in a direction perpendicular to the substrate surface, so that the waveguide loss in the waveguide is reduced. Can be reduced.

An eighth method for manufacturing a nitride semiconductor device according to the present invention achieves the third and fourth objects and forms a first nitride semiconductor layer on a substrate; Forming a plurality of first grooves extending in one direction in a substrate surface direction at intervals from each other on the nitride semiconductor layer; and forming a first mask film covering a bottom surface of the first grooves. A step of growing a second nitride semiconductor layer using a C-plane exposed from the first mask film between the respective first trenches on the upper surface of the first nitride semiconductor layer as a seed crystal; Above the second nitride semiconductor layer, the position of the region extending between the grooves adjacent to each other and extending in one direction is spaced apart from the position of the region between the first grooves in the substrate surface direction. Forming a plurality of different second grooves, and a second mask covering a bottom surface of the second grooves. Forming a third nitride semiconductor including an active layer, using a C-plane exposed from the second mask film between the respective second trenches on the upper surface of the second nitride semiconductor layer as a seed crystal. Forming a current confining portion on the third nitride semiconductor layer such that the resonance direction of the generated light is substantially orthogonal to the one direction.

According to the eighth method for manufacturing a nitride semiconductor device, the third nitride semiconductor device of the present invention can be reliably obtained.

A ninth method for manufacturing a nitride semiconductor device according to the present invention achieves the third and fourth objects and forms a first nitride semiconductor layer on a substrate; A step of forming a plurality of first grooves extending in one direction in the direction of the substrate surface at intervals above the nitride semiconductor layer, and covering a bottom surface of the first groove and at least a part of a wall surface thereof A step of forming a first mask film and a step of forming a second nitride semiconductor on a region exposed from the first mask film between the respective first trenches on the first nitride semiconductor layer as a seed crystal A step of growing a layer, and a step of, in the upper part of the second nitride semiconductor layer, extending in one direction at a distance from each other and setting a region between the adjacent grooves to a region between the first grooves. Forming a plurality of second grooves different from each other in the direction of the substrate surface and the second groove Forming a second mask film that covers the bottom surface of the semiconductor device and at least a part of the wall surface thereof, and exposing the second mask film between the respective second trenches on the second nitride semiconductor layer. Forming a third nitride semiconductor layer including an active layer using the region as a seed crystal; and forming a current on the third nitride semiconductor layer such that a resonance direction of generated light is substantially orthogonal to one direction. Forming a constriction.

According to the ninth method for manufacturing a nitride semiconductor device, the third nitride semiconductor device of the present invention can be reliably obtained.

The semiconductor light emitting device according to the present invention is characterized in that the fifth
A first semiconductor layer formed on the substrate and having a plurality of first projections extending in the direction of the substrate surface at intervals above the first semiconductor layer; A plurality of second protrusions formed in contact with the protrusions and having an upper portion in the same direction as the first protrusions and extending at a distance different from the distance between the first protrusions; A second semiconductor layer formed of a stacked body including a layer, and carriers are injected into the active layer from one of the plurality of second protrusions.

In general, the second semiconductor layer obtained by the ELOG method has a large number of threading dislocations in a region above the first convex portion. Therefore, it is necessary to provide a current injection region avoiding the region. According to the semiconductor light emitting device of the present invention, since a difference is provided between the formation period of the first protrusion and the formation period of the second protrusion, on the substrate, A region where the first convex portion and the second convex portion coincide with each other with a large period appears. If this large cycle is used, a mark for alignment can be easily and reliably attached, so that the yield and throughput of the manufacturing process are improved.

A first method for manufacturing a semiconductor light emitting device according to the present invention achieves the fifth object, forms a first semiconductor layer on a substrate, and forms the first semiconductor layer on the formed first semiconductor layer. Forming a plurality of first protrusions extending at intervals in the direction of the substrate surface; and forming a laminate on the first semiconductor layer, the lower surface of which is in contact with the first protrusion and includes an active layer. The second consisting of
And a plurality of second protrusions extending in the same direction as the first protrusions and extending at different intervals from the first protrusions on the formed second semiconductor layer. Forming, forming a mark on the substrate for alignment of a mask for selecting a protrusion for injecting carriers into the active layer from among the plurality of second protrusions, and aligning the mask with the mark. And performing a step of using one of the plurality of second convex portions as a carrier injection portion using a mask.

According to the first method for manufacturing a semiconductor light emitting device, the semiconductor light emitting device of the present invention can be reliably obtained.

A second method for manufacturing a semiconductor light emitting device according to the present invention achieves the fifth object, a step of forming a first nitride semiconductor layer on a substrate, and a step of forming the first nitride semiconductor layer. Forming a plurality of grooves extending apart from each other in the substrate surface direction, forming a mask film covering a bottom surface of the grooves, forming a plurality of grooves on the upper surface of the first nitride semiconductor layer. A second nitride semiconductor layer and a third nitride semiconductor layer having an energy gap smaller than that of the second nitride semiconductor layer from the substrate side with the C-plane exposed from the mask film therebetween as a seed crystal. Growing the stacked body so as to include the active layer and the fourth nitride semiconductor layer having a larger energy gap than the active layer; Extending at intervals different from the spacing between A step of forming a plurality of protrusions, and a carrier injection unit for injecting a carrier into the active layer by selecting a protrusion located above the groove and near a region between the grooves among the plurality of protrusions. Forming a step.

According to the second method for manufacturing a semiconductor light emitting device, the semiconductor light emitting device of the present invention can be reliably obtained.

A third method for manufacturing a semiconductor light emitting device according to the present invention achieves the fifth object, a step of forming a first nitride semiconductor layer on a substrate, and a step of forming the first nitride semiconductor layer. Forming a plurality of grooves extending at a distance from each other in the direction of the substrate surface, forming a mask film covering a bottom surface of the grooves and at least a part of the wall surface thereof, and a first nitride semiconductor. A region exposed from the mask film between the respective trenches on the layer is used as a seed crystal to form, from the substrate side, a second nitride semiconductor layer and a third nitride semiconductor layer having an energy gap smaller than that of the second nitride semiconductor layer. Growing a stacked body so as to include an active layer made of a nitride semiconductor layer of the above and a fourth nitride semiconductor layer having an energy gap larger than that of the active layer; And between the grooves Forming a plurality of protrusions extending at an interval different from that of the plurality of protrusions, selecting a protrusion located above the groove and in the vicinity of a region between the grooves, and selecting the protrusion. Forming a carrier injection portion for injecting carriers into the active layer.

According to the third method for manufacturing a semiconductor light emitting device, the semiconductor light emitting device of the present invention can be reliably obtained.

[0080]

(First Embodiment) A first embodiment of the present invention.
An embodiment will be described with reference to the drawings.

FIG. 1 shows a sectional structure of a gallium nitride based semiconductor laser device according to the first embodiment of the present invention.

As shown in FIG. 1, sapphire (crystalline A
l ₂ O ₃₎ on a substrate 11 made of the gallium nitride (Ga
N) through a low-temperature buffer layer (not shown)
A seed layer 12 made of GaN for LOG is formed.

On the upper portion of the seed layer 12, stripe-shaped protrusions 12a extending at intervals in the substrate surface direction are formed, and each recess (groove) sandwiched between the protrusions 12a.
Silicon nitride (SiN _x ) on the bottom and wall surfaces of 12b
Are formed, respectively.

On the seed layer 12, a selective growth layer 14 made of GaN is formed so as to be in contact with each of the projections 12a so that a gap 12c is provided between the lower surface thereof and the bottom of the groove 12b. .

Here, the seed layer 12 and the selective growth layer 14
The group III element is not limited to gallium but may include aluminum or indium. That is, the seed layer 12 and the selective growth layer _{14, Al u Ga v In w N} ( where, u, v, w is, 0 ≦ u, v, w ≦ 1, u + v + w =
It is one. ).

On the selective growth layer 14, a laminated body 30 composed of a plurality of nitride semiconductor layers including a double hetero junction forming a laser element is formed.

That is, the stacked body 30 is formed by the selective growth layer 14.
N-type contact layer 15 made of n-type GaN, an n-type cladding layer 16 made of n-type Al _0.07 Ga _0.93 N, an n-type light guide layer 17 made of n-type GaN, and a thickness of about 3 nm. of Ga _0.8 in _{0 .2} multiple quantum well well layers and thickness of N is composed of a barrier layer of about 6nm of GaN (MQW) active layer 18, made of p-type GaN p-type optical guide layer 19, It has a p-type cladding layer 20 made of p-type Al _0.07 Ga _0.93 N and a p-type contact layer 21 made of p-type GaN.

As is known, in the double heterojunction laser structure, the energy gap of the well layer containing indium in the MQW active layer 18 has the energy gap of the n-type and p-type cladding layers 16 and 20 containing aluminum. Smaller than the gap. On the other hand, the refractive index of light is the largest in the well layer of the MQW active layer 18, and hereinafter, the light guide layer 17,
19, the cladding layers 16 and 20 become smaller in this order.

The upper portion of the p-type cladding layer 20 and the p-type contact layer 21 are current injection regions having a width of about 3 μm to 5 μm, and a ridge portion 31 serving as a current confinement portion is formed.

The laminate 30 including the MQW active layer 18 has n
The etching is performed so that a part of the mold contact layer 15 is exposed, and the upper surface and side surfaces of the etched stacked body 30 are covered with the insulating film 22 made of silicon oxide.

P-type contact layer 21 in insulating film 22
An opening parallel to the protruding portion 12a is provided above the ridge portion 31. Nickel (Ni) which is in ohmic contact with the p-type contact layer 21 through the opening is formed in the region above and on the side of the ridge 31 on the insulating film 22. Composed of a laminate of gold and gold (Au)
Side electrodes 23 are formed.

On the exposed portion of the n-type contact layer 15 from the insulating film 22, an n-side electrode 24 made of a laminate of titanium (Ti) and aluminum (Al) is formed in ohmic contact with the n-type contact layer 15. Have been.

Here, the ridge portion 31 is formed in a low dislocation density region with a small number of crystal dislocations located above the void portion 12c.

Hereinafter, a method of manufacturing the semiconductor laser device configured as described above will be described with reference to the drawings.

FIGS. 2A, 2B, and 4 show cross-sectional structures in the order of steps of a method for manufacturing a semiconductor laser device according to the first embodiment of the present invention.

First, as shown in FIG. 2A, for example,
Using the MOVPE method, the substrate temperature is set to about 500 ° C. to 530 ° C.
After setting the temperature to ° C., trimethyl gallium (TM) as a group III source
G) and ammonia (NH ₃ ) as a nitrogen source,
A low temperature buffer layer (not shown) made of GaN is deposited. Then, after raising the substrate temperature to about 1020 ° C. to 1030 ° C., TMG and NH ₃ are supplied onto the substrate 11 to grow the seed layer 12 made of GaN.

Next, as shown in FIG. 2B, after a resist film is applied on the upper surface of the seed layer 12, the applied resist film is patterned in a stripe shape by photolithography to form a resist pattern 40. Form. Subsequently, dry etching is performed on the seed layer 12 using the resist pattern 40 as a mask, so that the protrusions 1 having a sectional width of about 3 μm are formed on the seed layer 12.
A periodic structure having one cycle of 2a and a groove (recess) 12b having a sectional width of about 12 μm is formed.

Next, as shown in FIG. 3A, a mask made of silicon nitride is formed on the resist pattern 40 on the bottom and wall surfaces of the groove 12b in the seed layer 12 by using electron cyclotron resonance (ECR) sputtering. A film 13 is deposited. Here, solid silicon is used as a silicon raw material, nitrogen is used as a reactive gas, and argon is used as a plasma gas. As described above, by using the ECR sputtering method for depositing the mask film 13, a high-quality mask film 13 can be obtained at a low temperature.

Next, as shown in FIG. 3B, the resist pattern 40 is lifted off to remove the resist pattern 40 and the mask film 13 on the resist pattern 40. The mask film 13 may cover the entire wall surface of the groove 12b, or may cover a part of the wall surface.

Next, as shown in FIG.
A selective growth layer 14 made of GaN is grown on the seed layer 12 by using the C-plane appearing on the top surface of the projection 12a exposed from the mask film 13 as a seed crystal. At this time, the selective growth layer 14 grows upward from the top surface of each projection 12a, and also grows (laterally grows) in a direction parallel to the substrate surface, and the crystal grown from both sides of each groove 12b. The mutually opposing side surfaces are joined substantially at the center of the groove 12b to form a joint 14a. As a result, the crystals grown from the top surfaces of the plurality of projections 12a are integrated, and the upper surface becomes the C plane. Subsequently, on the integrated selective growth layer 14, the n-type contact layer 15, the n-type cladding layer 16, the n-type light guide layer 17, the MQW active layer 1
8. A stacked body 30 is formed by sequentially growing the p-type light guide layer 19, the p-type cladding layer 20, and the p-type contact layer 21.

Thereafter, as shown in FIG. 1, the MW is applied to the upper part of the p-type cladding layer 20 and the p-type contact layer 21.
Ridge part 31 for selectively injecting current into Q active layer 18
Is formed in a low dislocation density region including a region above the void portion 12c and not overlapping the bonding portion 14a.

Subsequently, the ridge portion 31 of the laminate 30
Dry etching is performed on the area not containing
After exposing the n-type contact layer 15, the insulating film 22 is deposited on the exposed surface of the stacked body 30. Thereafter, the upper portion of the ridge portion 31 and the n-type contact layer 15 in the insulating film 22 are formed.
After selectively providing openings in the upper portion of the substrate, a p-side electrode 23 is formed on the exposed region of the ridge portion 31 from the opening of the insulating film 22 and on the side thereof by vapor deposition or sputtering. Then, an n-side electrode 24 is formed on a region of the n-type contact layer 15 exposed from the opening of the insulating film 22.

When a predetermined forward voltage is applied between the p-side electrode 23 and the n-side electrode 24 to the semiconductor laser device thus obtained, the p-side electrode 23 moves toward the MQW active layer 18. Holes are injected from 23 and electrons are injected from the n-side electrode 24, causing an optical gain in the MQW active layer 18 to cause laser oscillation with an oscillation wavelength of about 404 nm.

As shown in FIG. 5, a high dislocation density region 14b having a dislocation density of about 1 × 10 ⁹ cm ⁻² is formed in a region above the seed crystal in the selective growth layer 14, that is, a region above the convex portion 12a. Is done. On the other hand, the laterally grown region has a low dislocation density region 14 having a dislocation density of about 1 × 10 ⁷ cm ^−2.
c. Therefore, the reliability of the laser element can be improved by forming the ridge portion 31, that is, the current injection region serving as the laser beam resonator, above the low dislocation density region 14c in the stacked body 30.

The effect of the groove 12b of the seed layer 12, which is a feature of this embodiment, will be described with reference to FIGS. 6 (a) to 6 (d).

As shown in FIG. 6A, a stripe-shaped groove 12b is formed on the seed layer 12, and then a mask film 13 is formed on at least the bottom of the groove.

Next, as shown in FIGS. 6B and 6C, when the selective growth layer 14 is grown using the top surface of the convex portion 12a sandwiched between the groove portions 12b as a seed crystal, a mask is formed. In some cases, a polycrystalline body 41 made of GaN is deposited on the film 13.

Next, as shown in FIG. 6D, the ELO growth is continued while the polycrystal 41 is deposited, and the selective growth layer 1 is formed.
Even if 4 are integrated, a step is formed between the top surface of convex portion 12a, which is a seed crystal, and the bottom surface of groove 12b on which polycrystal 41 is deposited. Does not affect the crystallinity of the selective growth layer 14 and the stacked body 30 at all. As a result, the variation in the crystallinity of the stacked body 30 can be greatly reduced, and the production yield of the semiconductor laser device can be greatly improved.

By the way, the joint 14a penetrates the selective growth layer 14 and the laminated body 30 shown in FIG. 1 in a direction perpendicular to the substrate surface.
In (2), edge dislocations are concentrated to form a small-angle grain boundary. Therefore, electrons injected from the n-side electrode 24 cross the plurality of junctions 14a and reach the MQW active layer 18, but dislocations concentrated on the junctions 14a do not prevent injection of electrons.

Further, when the semiconductor laser device is formed in a chip shape, it is necessary to form a cavity end surface which is a mirror surface of the cavity. In general, the cavity facet of the semiconductor laser device is formed by cleaving the substrate 11, but at the time of cleavage, the substrate 11 may be damaged or cracked.

In the manufacturing method according to the second conventional example shown in FIG. 39, since the substrate 401 and the lowermost semiconductor layer 404 are in contact with each other, the scratches generated on the substrate 401
As a result, the operation reaches the layered structure containing No. 06, and the operation and optical characteristics of the laser element are greatly impaired.

On the other hand, in the present embodiment, since the gap 12c is provided between the substrate 11 and the laminated body 30, a scratch generated on the substrate 11 can be stopped at the gap 12c. For this reason, the laminate 30
Can be significantly reduced.

The manufacturing method according to the first conventional example shown in FIG. 37 uses a substrate 30 made of sapphire or silicon carbide.
When a nitride semiconductor layer is grown on the substrate 1, the dislocation density of the crystal increases to about 10 ⁹ cm ⁻² . When a semiconductor crystal having such a high dislocation density is grown in a step flow, the steps on the crystal surface are terminated by high-density dislocations, particularly screw dislocations, and microfacets are formed on the crystal surface. For this reason, the unevenness of the crystal surface becomes large and the crystal becomes poor in flatness. As a result, when growing the MQW active layer 306 containing indium, the amount of indium as a raw material incorporated into the growing crystal varies, which has an adverse effect such as an increase in the threshold current of the laser element. Occurs.

According to the manufacturing method of this embodiment, FIG.
In the lateral growth region, that is, the low dislocation density region 14c, uniform step flow growth was observed, and the flatness of the crystal surface was good. As a result, MQ
Even when the W active layer 18 is grown, local segregation of indium does not occur, so that the threshold current can be reduced.

In this embodiment, the MOVPE method is used for growing the nitride semiconductor. However, the present invention is not limited to this. Instead of the MOVPE method, any method capable of growing a nitride semiconductor, such as a hydride vapor phase epitaxy (HVPE) method or a molecular beam epitaxy (MBE) method, may be used. The same applies to each embodiment described later.

Further, although sapphire was used for the substrate 11,
Instead of sapphire, for example, silicon carbide, neodymium gallate (NGO), gallium nitride, or the like may be used.

Although the seed layer 12 is formed by two-step growth with a low-temperature buffer layer between the seed layer 12 and the substrate 11, the low-temperature buffer layer is not necessarily required if a single crystal can be obtained on the seed layer 12. is not.

Further, the lift-off method was used to form the protrusions 12a on the seed layer 12, but the protrusions 12a and the grooves 1a were formed.
2b may be formed, as long as the mask film 13 remains on at least the bottom surface of the groove 12b. In other words, any method may be used as long as the void 12c is formed using the C plane of the region of the protrusion 12a that is not covered by the mask 13 as a seed crystal. Further, instead of forming the protrusions 12a by recess etching in which the upper part of the seed layer 12 is dug, a mask film for selective growth having a stripe-shaped opening pattern is formed on the flat upper surface of the seed layer 12, and the mask film is formed. A convex portion protruding from the opening pattern of the film and growing may be used.

The mask film 13 may be formed only on the bottom surface of the groove 12b as long as the space 12c is formed.

Although silicon nitride is used as the material of the mask film 13, another dielectric film or an amorphous insulating film may be used instead of silicon nitride. Specifically, silicon oxide (SiO ₂ ), silicon oxynitride (SiON), aluminum oxide (Al ₂ O ₃ ), aluminum nitride oxide (AlNO), titanium oxide (TiO ₂ ), zirconium oxide (ZrO ₂ ) or oxidized Niobium (Nb ₂ O ₃ ) may be used. These films can be formed relatively easily by using the ECR sputtering method.

(First Modification of First Embodiment) Hereinafter, as a first modification of the first embodiment of the present invention, an example in which a refractory metal or a refractory metal is used for a mask film will be described.

When tungsten (W), which is a high melting point metal, is used for the mask film 13 for selective growth, the selectivity of crystal growth is improved as compared with the case where a dielectric is used for the mask film 13. Of the polycrystalline body 41 is further suppressed. Thus, a high-quality laminate 30 that is not affected by the polycrystalline body 41 can be formed very easily.

This is because the mask film 13 made of a metal has a weaker bonding force with the nitride semiconductor crystal than the mask film 13 made of a dielectric.

Further, tungsten, which is a high melting point metal,
Since its melting point is 3380 ° C., which has the highest melting point and the lowest vapor pressure of metal and its characteristics are stable, impurities such as silicon and oxygen when a dielectric such as silicon oxide is used enter the selective growth layer 14. There is no risk of mixing. Therefore, a deep level or a non-light-emitting center is not formed in the selective growth layer 14 grown using the mask film 13 made of tungsten.

FIG. 7 shows a selective growth layer 14 using a mask film 13 made of a dielectric and a mask film 13 made of a high melting point metal.
4 shows the result of comparing the photoluminescence at room temperature with the selective growth layer 14 using.

As shown in FIG. 7, the selective growth layer 14 according to the first modification does not emit light from a deep level having a wavelength of around 430 nm, and obtains extremely strong band-edge emission. This indicates that a higher quality crystal can be obtained as compared with the selective growth layer 14 according to the first embodiment. Therefore, the stacked body 3 is formed on the high-quality selective growth layer 14.
0, the MQW active layer 18 with higher luminous efficiency
Can be formed.

Although tungsten is used for the mask film 13 according to the first modification, another high melting point metal or a high melting point metallized material may be used instead. For example, molybdenum (Mo), niobium (Nb), tungsten silicide (WSi _x), it may be used molybdenum silicide (MoSi _x) or niobium silicide (NbSi _x). These films can be obtained relatively easily by using an electron beam evaporation method or a sputtering method.

(Second Modification of First Embodiment) FIG. 8 shows a cross-sectional structure of a gallium nitride based semiconductor laser device according to a second modification of the first embodiment of the present invention. In FIG. 8, the same components as those shown in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 8, the semiconductor laser device according to the second modification has n-type Al _0.07 Ga without providing a selective growth layer and an n-type contact layer on the seed layer 12.
_An n-type cladding layer 16 made of _0.93 N is provided.

As described in the first embodiment,
The groove 1 is formed above the seed layer 12 except for a region serving as a seed crystal.
Since 2b is formed, a gap 12c is formed above the mask film 13. As a result, even if a polycrystal is deposited on the mask film 13, the polycrystal is deposited on the seed layer 1.
2 are not taken into the semiconductor layer selectively grown on the semiconductor layer 2.
As a result, the crystallinity of the semiconductor layer to be selectively grown is improved, and the n-type cladding layer 16 which is a part of the stacked body 30 having the laser structure can be formed directly on the seed layer 12. In this case, the n-side electrode 24 is provided on the exposed portion of the exposed n-type cladding layer 16.

(Second Embodiment) Hereinafter, a second embodiment of the present invention will be described with reference to the drawings.

FIG. 9 shows a cross-sectional configuration of the gallium nitride based semiconductor laser device according to the second embodiment of the present invention, in which the M plane is a cavity end face. In FIG. 9, the same components as those shown in FIG.

In the semiconductor laser device according to the present embodiment, for example, a stripe-shaped convex portion 11a for selective growth is formed on the substrate 11A made of sapphire in a direction perpendicular to the M plane of the cavity end face, that is, on the substrate 11A. A axis (= <11-2
0>) direction.

Here, the n-type contact layer 15 is
The single crystal nucleus generated on the C plane of each convex portion 11a of 1A is directly formed as a seed crystal.

Hereinafter, a method of manufacturing the semiconductor laser device configured as described above will be described with reference to the drawings.

FIGS. 10 (a), 10 (b) to 12 show sectional structures of a semiconductor laser device according to the second embodiment of the present invention in the order of steps.

First, as shown in FIG. 10A, a resist film is applied on the substrate 11A having the C surface as a main surface, and the applied resist film is patterned into a stripe shape by photolithography. A stripe pattern extending in the A-axis direction of the substrate 11A has a period of about 10 μm.
A resist pattern 40 having a thickness of m to 30 μm is formed.
Subsequently, using the resist pattern 40 as a mask, a groove 11b having a sectional width of about 9 μm to 27 μm and a depth of about 20 nm to 500 nm is formed on the substrate 11A by dry etching such as reactive ion etching (RIE). Here, the cross-sectional width of the convex portion 11a formed of a region between the groove portions 11b is about 1 μm to 3 μm.

Next, as shown in FIG. 10B, the resist pattern 40 is removed to obtain a substrate 11A having a stripe-shaped convex portion 11a extending in the A-axis direction on the upper portion.

Next, as shown in FIG. 11, after the substrate temperature was raised to about 1000 ° C. by using the MOVPE method, for example, the pressure was about 100 Torr (1 Torr = 133.3).
22 Pa) as a mixed atmosphere of hydrogen and nitrogen,
Trimethylgallium (TMG), ammonia (NH ₃ ), and silane (SiH ₄ ) are supplied on 1A to form a substrate 1
On 1A, an n-type contact layer 15 made of n-type GaN is grown using a single crystal nucleus generated on the C-plane appearing on the top surface of the projection 11a as a seed crystal. At this time, the n-type contact layer 15 grows upward from the top surface of each convex portion 11a, and also grows in a direction parallel to the substrate surface, so that the crystals grown from both sides of the adjacent groove portion 11b are formed. The opposing side surfaces are joined at substantially the center of the groove 11b to form a joint 1
5a is formed. As a result, the respective crystals growing from the top surfaces of the plurality of projections 11a are integrated, and an n-type contact layer 15 having an upper surface formed of a C plane is formed. At this time, the bottom and wall surfaces of each groove 11b and the n-type contact layer 1
A plurality of gaps 11c surrounded by the lower surface of the fifth hole 5 are formed.

Here, the growth mechanism of the selective growth using the sapphire substrate 11A will be described.

Normally, when a nitride semiconductor is grown, when a substrate having a different lattice constant from that of the nitride semiconductor is used,
When a GaN crystal is directly grown on a substrate without a low-temperature buffer layer made of a nitride semiconductor, only a three-dimensional film in which single crystal nuclei made of GaN are united can be obtained.

On the other hand, in the present embodiment, the substrate 11A
Since the groove 11b is formed by dry etching, a damage layer due to dry etching is formed on the bottom and wall surfaces of the groove 11b. Therefore, the groove 11b
The formation of single crystal nuclei is inhibited on the bottom surface and the wall surface. In addition, since the cross-sectional width of the top surface of the convex portion 11a that has not been subjected to dry etching is as small as about 1 μm to 3 μm, high-density single crystal nuclei are easily generated. Thus, the convex portion 1
The single crystal nucleus generated on the top surface of 1a becomes a seed crystal for selective growth, and the selective growth in the substrate surface direction is promoted under the above-described growth conditions.

In FIG. 11, selection of parts other than the joint 15a is performed.
Threading dislocations are about 1 × 10 ⁶ cm^-2View at the density of
On the other hand, at the joint 15a,
About 4x10 dislocations⁷ cm^-2Observed at a density of n-type
The thickness of the contact layer 15 also depends on the width of the groove 11b and the like.
However, it is about 2 μm to 6 μm. Also, n-type contour
C-axis and air gap in the upper part of the protrusion 11a in the project layer 15
The tilt angle of the region on the part 11c with respect to the C axis is 0.01 degree or more.
It is suppressed to 0.03 degrees.

As described above, the tilt angle of the ELO growth method according to the present embodiment is extremely smaller than that of the conventional ELO growth because the n-type contact layer 15 which is the crystal layer grown by the ELO is in contact with the substrate 11A. The mask film 13
This is because stress unlike the conventional case does not occur at the interface with the substrate.

At this time, at the bottom of the joint 15a,
An inverted V-shaped void that opens toward the gap 11c appears.

Further, in the present embodiment, even when a polycrystalline substance is deposited on the bottom surface of trench 11b during the selective growth of n-type contact layer 15, projection 11a provided on top of substrate 11A has Since the polycrystalline body does not contact the n-type contact layer 15 due to the step generated between the polycrystalline body and the groove portion 11b, the crystal quality of the stacked body 30 is not adversely affected. As a result, it is possible to reduce the variation in the operating characteristics of the laser device formed from the stacked body 30 and improve the yield.

Next, as shown in FIG. 12, the remaining semiconductor layers of the stacked body 30 are formed on the n-type contact layer 15.

That is, for example, the substrate temperature is set to about 970 ° C.
Then, as a mixed atmosphere of hydrogen and nitrogen at a pressure of about 300 Torr, n
Clad layer 16, n-type light guide layer 17, MQW active layer 18, p-type light guide layer 19, p-type clad layer 20, p
The mold contact layer 21 is sequentially grown. Here, MQW
The active layer 18 is composed of a well layer made of Ga _0.92 In _0.08 N having a thickness of about 4 nm and a barrier layer made of GaN having a thickness of about 6 nm.

Subsequently, as shown in FIG. 9, with respect to the upper part of the p-type cladding layer 20 and the p-type contact layer 21, the M-axis (= <1-100>) direction of the stacked body 30, that is, the substrate 11A MWQ active layer 1 in a direction parallel to groove 11b
The ridge 31 for selectively injecting current into the gap 8
It is formed in a region above 1c and not overlapping with the joint 15a, that is, in a low dislocation density region. Here, the ridge 3
The width of 1 is about 2 μm to 5 μm.

Since the GaN-based crystal is transparent to visible light, the projection 11a and the void 11
c can be easily identified. Therefore, it is not necessary to use a dedicated alignment pattern when positioning the ridge 31 using the photolithography method.

Next, after exposing the n-type contact layer 15 by using a region of the laminate 30 not including the ridge portion 31 as a mask, an insulating film 22 is deposited on the exposed surface of the laminate 30. Subsequently, a p-side electrode 23 is formed on the insulating film 22 over the ridge portion 31 and on a region of the p-type contact layer 21 exposed from the insulating film 22. Further, an n-side electrode 24 is formed on a region of the n-type contact layer 15 exposed from the insulating film 22.

Next, the cavity end face is formed by cleaving the M surface of the laminated body 30, that is, the substrate 11A is cleaved at the A surface. As described above, the A-plane of sapphire is a crystal plane that is difficult to cleave, but even if the sapphire crystal breaks in a state in which the cleavage is shifted from a predetermined position by providing the gap 11c in the substrate 11A, Since this fracture does not propagate to the laminate 30, a good cleavage surface can be easily obtained in the vicinity of the cavity end face. Thereby, the yield due to cleavage of the laser element can be increased.

Next, a coating is applied to both end surfaces of the cleaved resonator with a dielectric film or the like so as to have an appropriate reflectivity. Obtain a laser device.

In the semiconductor laser device according to the present embodiment, as described in the first embodiment, uniform step flow growth is observed in the region where ELO has been grown. When the MQW active layer 18 is grown on such a flat surface, local segregation of indium does not occur. As a result, MQW
Since the active layer 18 is a high-quality crystal, the operating current of the laser element can be reduced.

FIG. 13 shows a far-field image of a laser beam emitted from the semiconductor laser device according to the present embodiment in a direction parallel to the cavity end face, and a light intensity distribution with good single-peak property is obtained. I have. On the other hand, the semiconductor laser device according to the first conventional example shows a far-field image in which the light intensity distribution is multimodal, as shown in FIG.

The semiconductor laser device according to the present embodiment can obtain a single-peak property because the gap 30c is provided between the stacked body 30 and the substrate 11A so that the stacked body 30 and the substrate 11A are optically connected. Because they are separated from each other.

More specifically, as shown in FIG.
Under the n-type cladding layer 16, the n-type cladding layer 16
Since the n-type contact layer 15 having a higher light refractive index is formed, light generated by the MQW active layer 18 easily leaks to the substrate 11A side. However, in the present embodiment, since the void 11c having an extremely low refractive index is provided below the n-type contact layer 15, a parasitic waveguide is formed between the n-type cladding layer 16 and the substrate 11A. Is not formed, and therefore, the MQW active layer 18 due to leakage of generated light.
This is because the value of the light confinement coefficient does not decrease.

It should be noted that the effect of preventing the generation of the parasitic waveguide is caused by the gap between the gap 11c in the direction perpendicular to the substrate surface,
That is, it depends on the depth of the groove 11b. According to the computer simulation, it has been confirmed that when the depth dimension of the groove 11b is at least about 50 nm, light leakage to the substrate 11A side is substantially eliminated.

The n-type contact layer 1 made of GaN
It has also been confirmed that when aluminum is added at 2% or more to 5, the leakage of light to the substrate 11A side can be more effectively suppressed.

In this embodiment, the substrate 11A
Of was used gallium nitride as the single crystal nuclei generated on the top surface of the convex portion 11a, a mixed crystal of other gallium nitride-based, _{i.e., Al u Ga v In w N} ( where, u, v, w are 0 ≦
u, v, w ≦ 1, u + v + w = 1. ). In the case of a mixed crystal, optimal growth conditions for ELO growth can be selected according to the composition of the mixed crystal.

Although sapphire is used for the substrate 11A, silicon carbide, gallium nitride, or the like may be used instead of sapphire. However, silicon carbide is used for the substrate 11A.
In this case, a tensile strain is applied to the stacked body 30 and cracks are easily generated. Therefore, the cross-sectional width of the groove 11b is made as small as possible, so that the n-type contact layer 15 is formed.
It is desirable that the film thickness when integrated is less than 2 μm. In addition, when silicon carbide or gallium nitride is used for the substrate 11A, cleavage is easy on any of the M-plane and the A-plane, but the cleavage is more easily performed on the plane orthogonal to the stripe direction of the groove 11b. it can.

Further, when the groove 11b is formed in the substrate 11A, dry etching by the RIE method is used. However, a damage layer is formed on the bottom surface and the wall surface of the groove 11b so that the gallium nitride based semiconductor can be selectively grown. If it is a method, another dry etching method, for example, an ion milling method may be used.

Although the damaged layer of the groove 11b is used as a mask layer for ELO growth, when the deposited polycrystal adheres to the damaged layer, particularly when gallium nitride is used for the substrate 11A, In order to further improve the selectivity, it is preferable to form a mask film made of silicon nitride or the like on at least the bottom surface of the groove 11b.

The mask film 13 is not limited to silicon nitride, but may be the dielectric or amorphous insulator described in the first embodiment. Further, the high melting point metal shown in the first modified example may be used. Alternatively, it is preferable to use a metal having a high melting point.

As described above, the invention according to the present embodiment relates to a laser device, but can also be applied as a method of manufacturing a semiconductor for obtaining a gallium nitride-based crystal having a low dislocation density. Furthermore, unlike the first embodiment, since the seed layer 12 is not provided on the substrate 11, the manufacturing process can be simplified.

Further, by using the nitride semiconductor layer having the low dislocation density region according to the present embodiment, not only the light emitting element but also other semiconductor elements such as an electronic element may be formed. Thereby, high reliability and high yield of the semiconductor element can be realized.

(Third Embodiment) Hereinafter, a third embodiment of the present invention will be described with reference to the drawings.

FIG. 14 shows a sectional structure of a gallium nitride based semiconductor laser device according to the third embodiment of the present invention. In FIG. 14, the same components as those shown in FIG.

Only the structural differences from the first embodiment will be described.

Aluminum gallium nitride (AlGaN) is used for the selective growth layer 14A which is grown from the top surface of each projection 12a of the seed layer 12 and integrated, and n-type AlGa is used.
An n-type superlattice cladding layer 16A having a superlattice structure including N and n-type GaN also serves as the n-type contact layer 15. Thereby, the light confinement coefficient value of the MQW active layer 18 is increased.

FIG. 15 shows the relationship between the refractive index distribution in the direction perpendicular to the substrate in the ridge portion of the semiconductor laser device according to the present embodiment and the light intensity distribution on the cavity facet. FIG. 16 shows a far-field image of a laser beam emitted from the semiconductor laser device according to the present embodiment in a direction parallel to the cavity end face.

In the third embodiment, the seed layer 12
The groove 12b has a depth of about 50 nm, and the average composition of the n-type superlattice cladding layer 16A is Al _0.07 Ga _0.93 N. The configuration of the stacked body above the n-type light guide layer 17 is equivalent to the configuration of the conventional semiconductor laser device shown in FIG.

As can be seen from FIG. 15, the semiconductor laser device according to the present embodiment does not show leakage of generated light to the substrate 11 side. In addition, it has been confirmed that the value of the light confinement coefficient of the light in the MQW active layer 18 reaches about 1.54 times that in the case of FIG.

This is because the MQW active layer 18 has the seed layer 1
In addition to being separated from the substrate 11 by the two voids 12c, the refractive index of light between the n-type superlattice cladding layer 16A and the seed layer 12 is smaller than or equal to that of the n-type superlattice cladding layer 16A. Is provided by providing the selective growth layer 14A made of n-type AlGaN having a refractive index of This allows
Since no parasitic waveguide is formed between the n-type superlattice cladding layer 16A and the substrate 11, a decrease in the light confinement coefficient value in the MQW active layer 18 due to leakage of generated light can be suppressed.

The effect of preventing the generation of the parasitic waveguide is attributable to the spacing of the gap 12c in the direction perpendicular to the substrate surface.
That is, it depends on the depth dimension of the groove 12b. As described above, if the depth of the groove 12b is at least about 50 nm, light leakage to the substrate 11 can be substantially eliminated.

Further, by setting the aluminum composition of the selective growth layer 14A to 2% or more, preferably 4% or more, leakage of generated light to the substrate 11 side can be suppressed.

Also in the present embodiment, when the selective growth layer 14A is grown, even if the ELO growth is continued while the polycrystalline body made of AlGaN is deposited on the mask film 13, the projections serving as seed crystals are formed. Since there is a step between the top surface of 12a and the bottom surface of the groove 12b on which the polycrystal is deposited,
The polycrystalline body does not deteriorate the crystallinity of the selective growth layer 14A. As a result, the variation in the crystallinity of the stacked body 30 can be greatly reduced, and the production yield of the semiconductor laser device is improved.

Hereinafter, a method of positioning the ridge portion 31 on the laminate 30 will be described.

In order to form the ridge portion 31 in the low dislocation density region above the void portion 12c in the laminate 30, it is necessary to position the ridge portion 31 with high accuracy by photolithography.

FIG. 17 shows a plan photograph of the selective growth layer 14 before forming the laminate 30 by an optical microscope, and a cross-sectional structure of the selective growth layer 14 corresponding thereto. As shown in FIG. 17, a low dislocation density region 14
c can be easily distinguished from the high dislocation density region 14b and the junction 14a. Therefore, it is not necessary to prepare a dedicated alignment pattern (alignment mark) in the step of positioning the ridge portion 31 by the photolithography method.

In order to form the resonator end face, it is necessary to cleave the substrate 11 and the laminate 30. Also in the present embodiment, since the gaps 12c provided in the seed layer 12 cause the scratches generated on the substrate 11 to stay in the gaps 12c, the influence on the stacked body 30 can be reliably reduced.

In this embodiment, the n-side electrode 24 is formed so as to be in contact with the n-type superlattice cladding layer 16A, and the n-type superlattice cladding layer 16A is used as an n-type contact layer.

As described above, the MQW active layer 18
In order to prevent the generated light from leaking to the substrate 11, an n-type light guide
Semiconductor containing aluminum between the layer 17 and the gap 12c
It must be composed of body layers. However, the n-side electrode
Aluminum for the n-type contact layer for forming
Layer (single layer) having a large composition of, for example, n-type Al
_0.07Ga_0.93When a single layer of N is used, the resistance of the single layer
The rate is about twice that of gallium nitride,
Drive current of the laser element
The pressure will increase.

As a result of various studies, the present inventors have found that, for example, the specific resistance of the n-type superlattice cladding layer 16A composed of n-type Al _0.14 Ga _0.86 N and n-type GaN is a single-layer n-type Ga
It has been found that the specific resistance is almost equal to the specific resistance of the N layer.
This is because the mobility of the two-dimensional electron gas generated in the superlattice semiconductor layer is large. Further, the inventors of the present application have set the thickness of the unit layer constituting the superlattice sufficiently small, for example, 2
nm, the contact resistance becomes n-type Ga.
It has also been found that it can be made equivalent to the N layer. At this time, the doping concentration of the n-type impurity is about 1 × 10 ¹⁸ cm ⁻³ .

Thus, by making AlGaN and GaN have a superlattice structure, it is possible to realize low resistance while utilizing the low refractive index of AlGaN, and to surely achieve low voltage.

The superlattice layer preferably has an average aluminum composition of 2% and a thickness of λ / (4n) or less. Here, λ is the wavelength of light, and n is the refractive index of the unit layer.

Further, according to the present embodiment, the low dislocation density region 14c of the selective growth layer 14A shown in FIG. 17 has a uniform step flow growth as measured by an atomic force microscope (AFM). Have been confirmed, and the surface has good flatness. As a result, when the MQW active layer 18 containing indium is grown, local segregation of indium does not occur, so that the threshold current can be reduced.

Although sapphire was used for the substrate 11,
Instead of sapphire, for example, silicon carbide, neodymium gallate (NGO), gallium nitride, or the like may be used.

The lift-off method was used to form the protrusions 12a on the seed layer 12, but the protrusions 12a and the grooves 1a were not used.
2b can be formed as long as the mask film 13 remains on at least the bottom surface of the groove 12b.

The mask film 13 may be formed only on the bottom surface of the groove 12b, as long as the space 12c is formed.

For the mask film 13, a dielectric such as silicon nitride or silicon oxide by ECR sputtering may be used, and more preferably, a high melting point metal such as tungsten or a silicide thereof is used.

(Fourth Embodiment) Hereinafter, a fourth embodiment of the present invention will be described with reference to the drawings.

FIG. 18 shows a sectional structure of a gallium nitride based semiconductor laser device according to the fourth embodiment of the present invention. In FIG. 18, the same components as those shown in FIG.

Only differences in structure from the third embodiment will be described.

As shown in FIG. 18, the selective growth layer 14A made of AlGaN according to the third embodiment is
A first selective growth layer 14B made of GaN formed near the top surface of the second protrusion 12a;
It has a two-layer structure with the second selective growth 14C made of AlGaN, which covers the upper side and the side of B.

The n-type superlattice cladding layer 16A also serving as the n-type contact layer is replaced with the n-type superlattice contact layer 15A.
And n-type cladding layer 1 composed of a single layer of Al _0.07 Ga _0.93 N
6 has a two-layer structure. Here, it is the structure of the n-type superlattice contact layer 15A, a superlattice structure composed of a n-type Al _0.1 Ga _0.9 N and n-type GaN.

Further, on the ridge portion 31 on the upper part of the stacked body 30, the p-side electrode 23 is formed only on the upper surface of the ridge portion 31, and the p-side wiring electrode is formed so as to cover the p-side electrode 23 and the ridge portion 31. 25 are formed. Similarly, an n-side wiring electrode 26 that covers the n-side electrode 24 is formed on the n-side electrode 24.

The features of the method for manufacturing a semiconductor laser device according to the present embodiment will be described below.

First, a plurality of first selective growth layers 14B which grow as a seed crystal using the top surface of each projection 12a of the seed layer 12 as a seed crystal
Grow. Subsequently, the first and second selective growth layers 14C are joined until the second selective growth layers 14C, which grow using the first selective growth layers 14B as seed crystals, are joined and integrated.
The growth pressures of B and 14C are set relatively low at about 200 Torr.

This is because the more the pressure is reduced, the more the first and second
This is because the growth rate of the selective growth layers 14B and 14C is higher in the A-axis direction of the seed layer 12, that is, in the direction crossing the groove 12b than in the C-axis direction perpendicular to the substrate surface.

On the other hand, the MQW active layer 18 is formed by increasing the pressure during growth to about 300 Torr. This is because, when the growth pressure is increased, evaporation of indium having a high vapor pressure can be suppressed, and the crystal quality of the MQW active layer 18 is easily increased. Therefore, when forming the stacked body 30, the growth pressures of the first and second selective growth layers 14B and 14C are changed.

As described above, in the continuous nitride semiconductor growth process, in order to change the growth pressure, one crystal growth furnace capable of changing the growth pressure during operation may be used. Separate crystal growth furnaces set at a pressure may be used.

The semiconductor laser device according to the fourth embodiment shows the refractive index distribution and the light intensity distribution shown in FIG. 15 similarly to the third embodiment, and the far-field pattern of the emitted light shown in FIG. Have gained.

This is because the MQW active layer 18 has the seed layer 1
In addition to being separated from the substrate 11 by the two voids 12c, the refractive index of light between the n-type cladding layer 16 and the seed layer 12 is smaller than or equal to that of the n-type cladding layer 16A. Having the n-type superlattice contact layer 15A and the second
This is because the selective growth layer 14C is provided. As a result, no parasitic waveguide is formed between the n-type cladding layer 16 and the substrate 11, and a decrease in the light confinement coefficient value in the MQW active layer 18 due to leakage of generated light can be suppressed.

In the case of the present embodiment, as a result of computer simulation, it was confirmed that if the depth of the groove 12b is at least about 20 nm, light leakage to the substrate 11 can be substantially eliminated. I have.

By setting the aluminum composition of the second selective growth layer 14C to 2% or more, preferably 4% or more, leakage of generated light to the substrate 11 side can be suppressed.

With the above configuration, the value of the light confinement coefficient in the MQW active layer 18 is about 1.5 times that in FIG. 41, and the threshold current of the laser can be reduced.

Next, the selective growth method according to the present invention using the top surface of the projection 12a as a seed crystal, and the second conventional selective growth method shown in FIG. 38 in which a flat seed layer is masked in a stripe shape. The difference of the growth mechanism from the above will be described.

FIG. 19A schematically shows a selective growth mechanism according to the fourth embodiment, and FIG.
1 schematically shows a selective growth mechanism according to the conventional example.

As is well known, the reactive species are adsorbed, diffused and evaporated on the surface of the crystal and on the surface of the mask film before the reactive species composed of molecules and the like grow into a desired crystal. And so on. For example,
The atoms adsorbed on the GaN crystal surface diffuse on the terrace, which is the upper surface of the crystal surface. Further, the atoms adsorbed on the surface are crystallized at a step portion on the terrace called a step.

As shown in FIG. 19B, a conventional ELO
In the case of growth, the same process is performed on the mask film 403. That is, the atoms diffused on the mask film 403 are adsorbed to the edge of the semiconductor layer 404 made of GaN. At this time, silicon or oxygen included in the mask film 403 is decomposed by the reducing action of hydrogen or ammonia and is taken into the semiconductor layer 404 as an impurity, so that the crystallinity of the semiconductor layer 404 is deteriorated.

On the other hand, as shown in FIG. 19A, in this embodiment, there are no atoms that diffuse on the mask film 13 and are taken into the first selective growth layer 14B made of GaN. This is because crystals cannot grow on the lower surface of the first selective growth layer 14B. As described above, the contribution of the reactive species on the mask film 13 to the crystal growth is caused by the conventional ELO.
Therefore, the growth mechanism of the present invention is different from the conventional ELO growth mechanism.

In this embodiment, GaN is used for the first selective growth layer 14B, and Al is used for the second selective growth layer 14C.
_{Although 0.05} Ga _0.95 N was used, the first selective growth layer 14B had an Al _x Ga _y In composition of 4% or less in aluminum.
_Any nitride semiconductor made of zN (x + y + z = 1) may be used.

Hereinafter, the purpose of forming the first selective growth layer 14B using the seed layer 12 as a seed crystal before growing the second selective growth layer 14C having a low refractive index will be described with reference to the drawings. I do.

As described in the third embodiment, the lateral mode control in the direction perpendicular to the substrate surface and the MQW active layer 1
If the value of the light confinement coefficient of light to 8 is increased, the selective growth layer does not need to have a two-layer structure.

However, as shown in FIG.
When the composition of aluminum in the selective growth layer 14A made of lGaN exceeds 4%, undulations 14d may be generated on the end face in the growth direction of the selective growth layer 14A. The growth conditions of the selective growth layer 14A, for example, growth pressure, growth temperature, or V / II which is a molar ratio of a group V source to a group III source.
Although a slight improvement can be achieved by setting an appropriate value for the I ratio or the like, it is preferable to minimize the generation of the undulation 14d on the growth end face in consideration of mass production.

The present inventors have found that it is preferable to use a nitride semiconductor layer having a low aluminum composition for the selective growth layer using the seed layer 12 as a seed crystal.

More specifically, as shown in FIG.
First, the first selective growth layer 14B made of a gallium nitride-based semiconductor having a composition of aluminum of 4% or less is used as the seed layer 12.
The second selective growth layer 14B is used as a seed crystal, and then the second selective growth layer 14B is formed of a gallium nitride based semiconductor having a composition of aluminum exceeding 4% and having a low refractive index. The selective growth layer 14C is grown. As a result, the second selective growth layer 14C undulates on the growth end face.
Good lateral growth without 4d can be achieved.

In the second selective growth layer 14C, the polycrystalline body 41 is more likely to be deposited on the mask film 13 as the composition of aluminum is larger and the growth time is longer. This is because AlGaN crystal or A
This is because the evaporation rate of the 1N crystal is low.

As shown in FIGS. 21 (a) to 21 (d), the first layer made of GaN and in which the polycrystalline body 41 is difficult to deposit is formed.
By growing the selective growth layer 14B first, the growth time of the second selective growth layer 14C required until the growth end faces are joined can be shortened.

FIG. 21C shows the first selective growth layer 14.
Since B grows in an umbrella shape, the amount of reactive species supplied on the mask film 13 can be reduced. With these effects, the amount of the polycrystalline body 41 deposited on the mask film 13 can be greatly reduced, and the influence on the stacked body 30 growing above the void portion 12c can be extremely reduced. As a result, the light confinement coefficient value can be reliably increased, and the laminate 3
Since the crystallinity of 0 is improved and the variation in the operating characteristics of the laser device can be greatly reduced, the production yield can be surely improved.

Although sapphire is used for the substrate 11 in the present embodiment, for example, silicon carbide, neodymium gallate, gallium nitride, or the like may be used instead of sapphire.

The mask film 13 may be formed only on the bottom surface of the groove 12b as long as the space 12c is formed.

The mask film 13 may be made of a dielectric such as silicon nitride or silicon oxide by ECR sputtering, and more preferably, a high melting point metal such as tungsten or a silicide thereof.

(Fifth Embodiment) Hereinafter, a fifth embodiment of the present invention will be described with reference to the drawings.

FIGS. 22 and 23 show a gallium nitride based semiconductor laser device according to a fifth embodiment of the present invention. FIG. 22 shows a cross-sectional structure of the stacked body on the M-plane, that is, a cross-sectional structure on the A-plane of the substrate. XXIII-X of FIG. 23 and FIG.
3 shows a cross section taken along the line XIII, and shows a cross-sectional configuration on the A plane of the laminate, that is, the M plane of the substrate. 22 and 23, the same components as those shown in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

The fifth embodiment is characterized in that a semiconductor laser device having a flat resonator end face 32 can be reliably formed from a laminate 30 including an MQW active layer 18.

As shown in FIG. 22, a convex portion 12a having a cross section width of about 3 μm and a
Enlarged groove portions 12d in which the cross-sectional width of the groove portion 12b is increased to about 20 μm are formed at every 34 periods (510 μm length) of the periodic structure having one period of the groove portion 12b of μm.

In the same manner as in the first embodiment, the laminate 30
Is formed, the stacked body 30 that laterally grows using the top surface of each convex portion 12a of the seed layer 12 as a seed crystal becomes the enlarged groove portion 1
Since it is not bonded above 2d, the adjacent stacked body 30
The growth end faces of the A-planes appear without contact with each other. Since this growth end face is a naturally formed crystal face, other face orientations such as the M face do not exist at all. Therefore, when this growth end face is used as the resonator end face 32, it is possible to prevent the mirror loss at the resonator end face caused by the mixture of the A-plane and the M-plane as in the conventional semiconductor laser device shown in FIG.

When the growth end face having the naturally formed A-plane is observed by an atomic force microscope (AFM), an extremely flat surface having an average squared roughness of 1 nm or less is obtained. Make sure that.

Further, assuming that the growth end face is a resonator end face 32, the p-type optical guide layer 19 and the p-type clad layer 20 having an energy gap larger than that of the MQW active layer 18 are formed on the resonator end face 32. , P-type light guide layer 1
The outgoing light is not absorbed in the regions on the end faces of the p-type cladding layer 9 and the p-type cladding layer 20. This suppresses a temperature rise in the vicinity of the resonator end face 32 in the stacked body 30, thereby preventing a decrease in reliability due to end face deterioration.

According to the semiconductor laser device of the fifth embodiment, the ELO growth method in which the top surface of the stripe-shaped protrusions 12a is used as a seed crystal is used, and further, the groove formed by the side surfaces of the protrusions 12a is used. The enlarged groove portion 12d is provided with a formation cycle of 12b larger than the formation cycle. As a result, the growth end face of the stacked body 30 is exposed as it is above the enlarged groove 12d, so that the naturally formed exposed face becomes the end face 32 of the resonator. Comparing the oscillation threshold of laser light between the semiconductor laser device according to the present embodiment having this cavity facet and the semiconductor laser device according to the second conventional example shown in FIG. 39, the laser device according to the present embodiment Reduces about 30%.

Although sapphire was used for the substrate 11,
Instead of sapphire, for example, silicon carbide, neodymium gallate (NGO), gallium nitride, or the like may be used.

The mask film 13 may be formed only on the bottom surface of the groove 12b if the space 12c is formed.

The mask film 13 may be made of a dielectric such as silicon nitride or silicon oxide by ECR sputtering, and more preferably, a high melting point metal such as tungsten or a silicide thereof.

The projection 1 provided above the seed layer 12
2a and the width of the groove 12b are 3 μm and 12 μm, respectively.
However, it is preferable that the width of the protrusion 12a be smaller than the width of the groove 12b. By doing so, the convex portion 1
The influence of dislocations propagating from the seed crystal on the top surface of 2a to the stacked body 30 can be reduced, and the operating characteristics of the laser element due to the dislocations can be prevented, so that the reliability of the laser element can be improved.

In addition, the enlarged groove 12 above the seed layer 12
The period for forming d may be set to an appropriate value in accordance with the length of the resonator.

In the fifth embodiment, the M-axis direction of the multilayer body 30 is selected as the stripe direction of the convex portion 12a, and the naturally formed A surface is used as the resonator end surface 32. When the direction of the A-axis orthogonal to the M-axis of the laminate 30 is selected as the stripe direction of the M, the M plane is naturally formed. Therefore, the stripe-shaped protrusions 12 extending in the A-axis direction are provided.
By forming a, it is possible to obtain a semiconductor laser device having a naturally formed M-plane at the cavity facet 32, capable of greatly reducing the threshold current and improving the reliability.

(First Modification of Fifth Embodiment) Hereinafter, a first modification of the fifth embodiment of the present invention will be described with reference to the drawings.

FIG. 24 is a cross-sectional view of a stacked body in a gallium nitride based semiconductor laser device according to a first modification of the fifth embodiment.
2 shows a cross-sectional configuration in the plane, that is, a cross-sectional configuration in the A-plane of the substrate. 24, the same components as those shown in FIG. 22 are denoted by the same reference numerals.

As shown in FIG. 24, in the semiconductor laser device according to the first modification, the cross-sectional width of the groove adjacent to the inside of the enlarged groove 12d which naturally forms the resonator end face 32 of the multilayer body 30 is reduced to about 20 μm. It has an enlarged groove 12d. Thereby, the side gap portions 30a each having the opposing surface formed of the A surface are formed at both end portions of the stacked body 30 on the resonator end surface side.
Are formed.

Thus, by combining the cavity end face 32 with the side gap 30a having a refractive index of 1 and the laminated body 30 made of a gallium nitride based semiconductor having a refractive index of about 2.6, a high refractive index is obtained. Since the difference in the refractive index can be realized, the reflectance of the laser light at the cavity end face 32 can be increased as compared with the case where the laser light is coated with a dielectric film or the like.

In order to increase the reflectivity of the laser beam at the resonator end face 32, the width of the isolated body separated from the stacked body 30 by the side gap 30a in the emission direction is λ / (4n).
Is preferably an integral multiple of Here, λ is the wavelength of light, and n is the refractive index of the isolated body.

Although the side gaps 30a are provided at both ends of the laminated body 30, only one of the end parts of the laminated body 30 has a side surface in order to increase the reflectance and increase the output value of the emitted light. A void 30a may be provided.

According to this modification, the lasing threshold current of the laser beam is smaller than that in the case where the side gap 30a is not provided.
It is reduced by about 20%, and the effect of the side gap 30a is extremely large. Note that three or more side surface gaps 30 a may be provided in the laminate 30.

(Second Modification of Fifth Embodiment) FIG.
Is a second modified example according to the fifth embodiment, and all the stripe-shaped grooves provided on the seed layer 12 are enlarged grooves 12d.

In this manner, each of the plurality of stacked bodies 30 becomes an isolated body on the substrate 11.
Therefore, a resonator consisting of a plurality of isolated bodies is formed so that a resonator having a desired resonator length is formed, and the substrate 11 is divided at the side surface gap 30a at a position corresponding to the end face of the formed resonator. Thereby, one semiconductor laser device including a plurality of isolated bodies can be formed.

As a result, the semiconductor laser device according to the second modified example has an extremely flat A surface without irregularities which causes a mirror loss of laser light, and changes the number of the laser devices including the isolated body. This makes it possible to easily change the resonator length.

Further, the substrate 1 is provided for each of the enlarged grooves 12d.
By dividing 1, it is also possible to obtain a laser element having one cavity 12 a and a cavity length of about 15 μm. In the conventional method of simultaneously cleaving the substrate and the stacked body, it is extremely difficult to form such a minute resonator while maintaining the flatness of the resonator end face.

(Third Modification of Fifth Embodiment) As a third modification, a stripe-shaped projection is further provided on the selective growth layer to completely eliminate crystal dislocations from the stacked body 30. A description will be given of a method for improving the reliability of the semiconductor laser device.

As shown in FIG. 26, a convex portion 12a and a groove portion 12b are provided on the upper portion, and a selective growth is performed on the seed layer 12a in which the first mask film 13A is formed on the bottom surface and the wall surface of the groove portion 12b. The seed layer 34 is integrally formed by ELO growth.

On the selective growth seed layer 34, the period is the same as that of the protrusions 12 a and the grooves 12 b of the seed layer 12.
A projection 34a and a groove 34b are provided.
A second mask film 13B is formed on the bottom and wall surfaces of 4b.

Here, the projection 34a is formed above the groove 12b so as to avoid the low dislocation density region and the junction in the selective growth seed layer 34.

As described above, according to the third modification, the selective growth layer 14 is grown using the C-plane, which is the top surface of the convex portion 34a provided above the selective growth seed layer 34, as a seed crystal. The top surface of the convex portion 34a has a high-quality crystal surface that does not include dislocations from the seed crystal on the top surface of the convex portion 12a in the seed layer 12 or defects caused by the junction of the selective growth seed layer 34. Appears. As a result, the stacked body 30 formed on the high-quality selective growth layer 14 is defect-free, and loss due to scattering of laser light due to crystal defects and reduction in reliability due to a non-light emitting process of carriers can be prevented. A very high quality gallium nitride based semiconductor laser device can be realized.

(Sixth Embodiment) Hereinafter, a sixth embodiment of the present invention will be described with reference to the drawings.

FIG. 27 shows a gallium nitride-based semiconductor laser device according to the sixth embodiment of the present invention, which shows a cross-sectional structure on the A-plane of the stacked body, that is, a M-plane of the substrate. In FIG. 27, the same components as those of the laser device according to the third embodiment shown in FIG.

Only the configuration differences from the third embodiment will be described.

As shown in FIG. 27, on a substrate 11 made of sapphire, a first seed layer 12A and a second seed layer 12B are provided.

On the first seed layer 12A, a stripe-shaped convex portion 12a and a groove portion 12b are provided in parallel with the M-plane of the substrate 11, that is, in parallel with the A-plane of the stacked body 30. ing. Similarly, on the upper part of the second seed layer 12B, a stripe-shaped protrusion 12a and a groove 12b are provided.
Are convex portions 12a and groove portions 12b of the first seed layer 12A.
Are provided so as not to overlap in a direction parallel to the substrate and in a direction perpendicular to the substrate surface.

Hereinafter, a method of manufacturing the semiconductor laser device having the above-described structure will be described with reference to the drawings.

FIGS. 28 (a), 28 (b) to 31 show a method of manufacturing a semiconductor laser device according to the sixth embodiment of the present invention. ing.

First, as shown in FIG.
By the PE method, the substrate temperature is set to about 530 ° C. on the substrate 11 having the C plane as the main surface, and the pressure is set to about 300 Torr, for example.
r as a mixed atmosphere of hydrogen and nitrogen,
G and a nitrogen source NH ₃ are supplied to deposit a low-temperature buffer layer made of GaN (not shown). Subsequently, after raising the substrate temperature to about 970 ° C., TMG, NH _3, and SiH ₄ are supplied onto the substrate 11 to form a first layer of n-type GaN having a thickness of about 0.5 μm to 1 μm. Is grown. At this time, the main surface of the first seed layer is the C plane, and the dislocation density is on the order of 10 ⁹ cm ⁻² .

Next, as shown in FIG. 28B, after a resist film is applied on the first seed layer 12A, the applied resist film is subjected to photolithography to make the stripe direction of the first seed layer 12A. The resist pattern 40 is formed by performing patterning that matches the M-axis direction. Subsequently, dry etching is performed on the first seed layer 12A using the resist pattern 40 as a mask, so that a convex portion 12a having a sectional width of about 3 μm to 6 μm is formed on the first seed layer 12A. Is about 12 μm
A periodic structure having the 24 μm groove 12b as one cycle is formed. At this time, the depth of the groove 12b is set to 50 nm or more.
It is about 1 μm.

Next, as shown in FIG.
Using a sputtering method, the bottom surface and the wall surface of the groove 12b in the first seed layer 12A and the resist pattern 40 are
A mask film 13 made of silicon nitride is deposited. Here, solid silicon is used as a silicon raw material, nitrogen is used as a reactive gas, and argon is used as a plasma gas.

Next, as shown in FIG. 29B, the resist pattern 40 is lifted off to remove the resist pattern 40 and the mask film 13 thereon.
Note that the mask film 13 may cover the entire wall surface of the groove 12b, or may cover a part of the wall surface.

Next, as shown in FIG.
Using the OVPE method, for example, a mixed atmosphere of hydrogen and nitrogen at a pressure of about 100 Torr is used, and a substrate temperature of about 1000 Torr is set.
After the temperature was raised to ° C., TMG, NH _3, and SiH ₄ were supplied onto the first seed layer 12A, so that the region of the first seed layer 12A exposed from the mask film 13 was used as a seed crystal to form n A second seed layer 12B made of type GaN is grown. At this time, the second seed layer 12B grows upward from the top surface of each projection 12a, and also grows in a direction parallel to the substrate surface, so that the crystals that have grown from both sides of the adjacent groove 12b. The opposing side surfaces of the groove 12
The bonding portion 12e is formed by bonding at substantially the center of b. As a result, the crystals grown from the top surfaces of the plurality of projections 12a are integrated, and the second seed layer 12B having the upper surface formed of the C plane is formed. At this time, a plurality of voids 12c are formed, which are surrounded by the bottom and wall surfaces of each groove 12b in the first seed layer 12A and the lower surface of the second seed layer 12B. At this time, the second seed layer 12
The thickness of B depends on the width of the groove 12b and the like.
μm to 6 μm.

The bonding portion 12 in the second seed layer 12B
In the selective growth region except for e, the dislocation density is about 1 × 10 ⁶ c
While threading dislocations of about m ⁻² are observed,
In e, the dislocation density parallel to the C plane is about 4 × 10 ⁷ cm ^−2.
Is observed.

The tilt angle between the C-axis of the upper portion of the protrusion 12a in the second seed layer 12B and the C-axis of the region above the gap 12c is 0.01 to 0.03 degrees.

As described above, the tilt angle of the ELO growth method according to the present embodiment is extremely smaller than that of the conventional ELO growth because the second seed layer 12B, which is the crystal layer grown by the ELO, is the first seed layer. This is because it does not come into contact with the seed layer 12A and does not generate stress at the interface with the mask film 13 as in the related art.

The gap 12 is formed below the joint 12e.
An inverted V-shaped void appears on the c side.

Further, in the present embodiment, even when a polycrystal is deposited on the bottom surface of trench 12b during selective growth of second seed layer 12B, first seed layer 1
The polycrystalline body is formed into the second seed layer 12B by a step formed by the protrusion 12a and the groove 12b provided on the upper part of the second seed layer 12B.
Therefore, there is no adverse effect on the crystal quality of the laminate 30 including the laser structure. As a result, the laminate 3
Variations in the operating characteristics of the laser element formed from 0 can be reduced, and the yield can be improved.

Next, as shown in FIG. 30B, on the grown second seed layer 12B, a periodic structure having one period of the protrusions 12a and the grooves 12b is provided on the first seed layer 1B.
It is formed by the same method as 2A. At this time, it is preferable to form the projection 12a of the second seed layer 12B such that the top surface thereof is located above the low dislocation density region of the second seed layer 12B. That is, the second seed layer 12B
The top surface of the projection 12a of the first seed layer 12A is different from the top surface of the projection 12a of the first seed layer 12A in the substrate surface direction, and is formed in a region on the side of the joint 12e.

Thus, the second ELO growth can be performed using the low dislocation density region in the second seed layer 12B located above the void portion 12c of the first seed layer 12A as a seed crystal. Since the gallium nitride-based crystal is transparent to visible light, the projection 12
a and the groove portion 12b can be easily identified, and it is not necessary to use a dedicated alignment pattern when positioning the convex portion 12a having a stripe pattern by photolithography.

Next, as shown in FIG.
Using, for example, hydrogen at a pressure of about 100 Torr and nitrogen.
And a substrate temperature of about 1000 ° C.
Then, the second seed layer 12B is exposed from the mask film 13 on the second seed layer 12B.
The C-plane appearing on the top surface of the projecting projection 12a is used as a seed crystal.
Thus, a selective component composed of n-type AlGaN and having a main surface composed of C-plane
The long layer 14A is grown until it is integrated. This
Thus, the selective growth layer 14A is formed at the bonding portion 14 formed periodically.
The dislocation density is about 1 × 10⁶ cm ^-2
And smaller.

Subsequently, an n-type superlattice cladding layer 16A, an n-type superlattice cladding layer 16A, Light guide layer 17, MQW active layer 18, p-type light guide layer 19, p-type cladding layer 20, and p-type
The stacked body 30 is formed by sequentially growing the mold contact layer 21. Here, the MQW active layer 18 has an oscillation wavelength of 400 nm.
In order to obtain a band laser oscillation, for example, a thickness of about 4
nm of Ga _0.92 In _0.08 N and a thickness of about 6 nm.
nm of GaN.

Then, as shown in FIG. 27, a current is selectively injected into the MWQ active layer 18 into the upper portion of the p-type cladding layer 20 and the p-type contact layer 21 by a dry etching method. The ridge portion 31 having a thickness of about 5 μm is formed in the A-axis direction of the laminate 30, that is, in the direction orthogonal to the stripe direction of the protrusion 12 a.

Subsequently, the ridge portion 31 in the laminate 30
Dry etching is performed on the area not containing
After exposing the n-type superlattice cladding layer 16A, the laminate 30
An insulating film 22 is deposited on the exposed surface. Subsequently, the insulating film 22
After the openings are respectively provided in the region above the ridge portion 31 and the region above the n-type superlattice cladding layer 16A, a portion from the opening of the insulating film 22 in the ridge portion 31 is formed by a vapor deposition method or a sputtering method. The p-side electrode 23 is formed on the exposed region and the peripheral portion of the ridge portion 31, and the n-side electrode 24 is formed on the exposed region of the n-type superlattice cladding layer 16A from the insulating film 22.

Next, a cavity end face is formed by cleaving the surface A of the laminate 30, that is, the M surface of the substrate 11 made of sapphire. The M-plane of sapphire can be easily cleaved, and the yield of cleavage of the semiconductor laser device can be favorably maintained. In addition, between the substrate 11 and the laminated body 30, there are a plurality of and two-stage gaps 12c extending parallel to the cleavage plane, but the gap 12c does not lower the cleavage yield. .

Next, the cleaved end faces are coated with a dielectric material or the like so as to obtain an appropriate reflectance, and separated into chips to realize a semiconductor laser device shown in FIG.

The semiconductor laser device according to the sixth embodiment has a resonator formed in the A-axis direction of the stacked body 30 including the MQW active layer 18 and a stripe-shaped extending in the M-axis direction formed by selective growth. It is characterized in that the gap portion 12c is provided so as to be orthogonal.

However, in this case, as can be seen from FIG. 31, the current injection region in the major axis direction of the ridge portion 31 of the MQW active layer 18 crosses the junction 14a of each semiconductor layer. As a result, there is a possibility that the dislocation concentrated on the joint portion 14a may affect the operation of the laser element. However, when dislocations in the layer of the MQW active layer 18 were observed, threading dislocations were found to be approximately 1 × 10
^It has been confirmed that it exists at a density of ⁶ cm ^-2 . Therefore, the fact that the current injection region crosses the junction 14a does not adversely affect the reliability of the semiconductor laser device.

Also, the second seed layer 12B as a seed crystal
If there is a tilt in the C-axis between the substrate and the selective growth layer 14A, the resonator formed in the A-axis direction becomes a zigzag waveguide undulating in a direction perpendicular to the substrate surface to reduce the waveguide loss. Invite. As a result, the operating current of the laser device may increase. Certainly, a conventional ELO as shown in FIG.
In a laser device manufactured by using the growth method, the tilt angle is set to 0.
If the width of the gap 12c is 12 microns, the zigzag waveguide has a height difference of 10 nm or more, and the operating current of the laser element increases.

On the other hand, if the tilt angle is less than 0.05 degrees, the height difference can be suppressed to about 5 nm, so that the influence of the zigzag waveguide can be almost ignored. In the present embodiment, the tilt angle can be suppressed to 0.03 degrees or less by the lateral growth of the bright laser element while forming the gap 12c, so that the generation of the zigzag waveguide can be prevented.

In the laterally grown region of the selective growth layer 14A, uniform step flow growth is observed. The MQW active layer 1 is formed on such a flat surface.
When the layer 8 is grown, a uniform segregation of indium does not occur and a homogeneous MQW active layer 18 can be obtained, so that the operating current can be reduced.

The far-field pattern in the direction perpendicular to the substrate surface in the semiconductor laser device according to the present embodiment is equivalent to the graph shown in FIG. 16, and a good light intensity distribution with a single peak is obtained. .

This is because, similarly to the third embodiment, n-type AlGaN is used for the selective growth layer 14A which is grown from the top surface of each projection 12a of the second seed layer 12B and integrated, and n-type AlGaN is used. The n-type superlattice cladding layer 16A having a superlattice structure including n-type AlGaN and n-type GaN also serves as an n-type contact layer. This is because the light confinement coefficient value of the MQW active layer 18 is greatly improved.

As described above, when the aluminum composition of the selective growth layer 14A is 2% or more, preferably 4% or more, it is possible to reliably prevent light from leaking to the substrate 11 side.

[0288] In the present embodiment, the first and second seed layers 12A, GaN is used to 12B, the general formula Al _u Ga _v In _w N (where, u, v, w are 0 ≦
u, v, w ≦ 1, u + v + w = 1. ), Especially AlGaN or GaInN, etc., and the optimum growth conditions for lateral growth may be selected according to the composition of the mixed crystal.

Although the first seed layer 12A is formed via the low-temperature buffer layer, a method that can obtain a single crystal in the first seed layer may be used.

Although sapphire was used for the substrate 11,
Instead of sapphire, for example, silicon carbide, neodymium gallate (NGO), gallium nitride, or the like may be used. However, when silicon carbide is used for the substrate 11, a tensile strain is applied to the laminate 30 and cracks are easily generated. Therefore, by reducing the cross-sectional width of the groove 12b as much as possible,
The film thickness when the second seed layer 12B is integrated is 2 μm.
It is desirable to make it less than m. In this way, cracks do not occur in the stacked body 30 even after the selective growth and the growth of the stacked body 30 twice.

Therefore, selective growth three or more times is meaningless irrespective of the material of the substrate 11, and furthermore, it causes a new problem due to distortion, which is not preferable.

Further, the first and second seed layers 12A, 12A,
Although the lift-off method was used when forming the upper convex portions 12a of 2B, other methods may be used as long as the convex portions 12a and the groove portions 12b can be formed and the mask film 13 remains on at least the bottom surface of the groove portions 12b. May be used. That is, the convex portion 1
Any method may be used as long as the voids 12c are formed by using the C plane of the region not covered by the mask 13 in 2a as a seed crystal.

The mask film 13 is not limited to silicon nitride, but may be made of the dielectric, amorphous insulator, high-melting metal or high-melting metal shown in the first embodiment and its first modification. Is preferred. In addition, EC is used for depositing the dielectric film.
By using the R sputtering method, a high-quality mask film 13 can be obtained at a low temperature.

Further, by using the nitride semiconductor layer having a low dislocation density region according to the present embodiment, not only a light emitting element but also another semiconductor element such as an electronic element may be formed. Thereby, high reliability and high yield of the semiconductor element can be realized.

(Seventh Embodiment) Hereinafter, a seventh embodiment of the present invention will be described with reference to the drawings.

FIG. 32 shows a sectional structure of a gallium nitride based semiconductor laser device according to the seventh embodiment of the present invention. 32, the same components as those shown in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 32, the semiconductor laser device according to the seventh embodiment becomes a seed crystal for ELO growth provided on the seed layer 12 and has a stripe-shaped convex having a first formation period. Part 12a, one ridge part 31A for current injection, and a plurality of dummy ridge parts 31 for positioning the ridge part 31A, which are provided on the stacked body 30.
B. The ridge portion 31A and the dummy ridge portion 31B are formed so as to extend in the same direction as the convex portion 12a and have a second formation cycle different from the first formation cycle.

Hereinafter, a method for manufacturing the semiconductor laser device having the above-described structure will be described with reference to the drawings.

FIGS. 33 to 35 show sectional structures in the order of steps of a method for manufacturing a semiconductor laser device according to the seventh embodiment of the present invention.

First, as shown in FIG. 33, a seed layer 12 made of GaN is grown on a substrate 11 made of first sapphire by MOVPE in the same manner as in the first embodiment, and a resist film is formed. A ridge stripe-shaped convex portion 12a is formed on the grown seed layer 12 by the used photolithography method and dry etching method. Here, as an example, the cross-sectional width of the projection 12a is about 4 μm, the cross-section width of the groove 12b is about 12 μm, and the first forming cycle is 16 μm.

Next, the projections 1 were formed by ECR sputtering.
Over the entire surface of the seed layer 12 on which 2a is formed,
Depositing a mask film 13 made of silicon nitride,
By lifting off the resist film, at least the top surface of the projection 12 a is exposed from the mask film 13. here,
The mask film 13 may or may not cover the wall surface of the groove 12b.

Then, as in the first embodiment, a selective growth layer is formed on the seed layer 12 by using the C-plane appearing on the top surface of the projection 12a exposed from the mask film 13 as a seed crystal by the MOVPE method. 14 and the stacked body 30 are sequentially grown.

Next, as shown in FIG. 34, the ridge portion having a second formation period of about 3 μm in cross-section and a period of 18 μm with respect to the upper part of the p-type cladding layer 20 and the p-type contact layer 21. 31A and a dummy ridge portion 31B are formed. Here, the ridge portion 31A for current injection is formed in a region above the void portion 12c and not overlapping with the bonding portion 14a, that is, a low dislocation density region having few crystal dislocations.
Thereafter, the sides of the ridge portion 31A and the dummy ridge portion 31B and a region therebetween are covered with an insulating film 35 made of aluminum nitride (AlN) by an ECR sputtering method using an atmosphere of argon and metal aluminum and nitrogen as raw materials.

Next, as shown in FIG. 35, the region not including the ridge portion 31A in the laminated body 30 is dry-etched to form the n-type contact layer 15 into the dummy ridge portion by the n-type cladding layer 16. After being exposed so that 31 is formed, an insulating film 22 made of silicon nitride is deposited on the exposed surface of the stacked body 30.

Next, as shown in FIG. 32, reactive ion etching (RIE) using carbon tetrafluoride (CF ₄ )
Accordingly, openings are provided in the insulating film 22 above and on the side portions of the ridge portion 31A and on the n-type contact layer 15 above and on the side portions of one dummy ridge portion 31B. Thereafter, the p-side electrode 23 is formed on the ridge portion 31A and the exposed region of the insulating film 22 on the side thereof from the opening, and the dummy ridge portion 31B on the n-type contact layer 15 and the insulating film on the side thereof are formed. An n-side electrode 24 is formed on a region exposed from the opening 22. When the upper and side portions of the ridge portion 31A in the insulating film 22 are removed, the insulating film 35 formed below the insulating film 22 is also slightly etched. If it does not affect the lateral mode control, it may be ignored.

The semiconductor laser device obtained as described above has an MQW active layer composed of a well layer made of Ga _0.8 In _0.2 N having a thickness of about 3 nm and a barrier layer made of GaN having a thickness of about 6 nm. Due to the layer 18, the wavelength is about 403 n
m laser oscillation.

Hereinafter, a method of aligning the ridge portion 31A and the dummy ridge portion 31B with the convex portion 12a, which is a feature of the method of manufacturing the semiconductor laser device according to the present embodiment, will be described with reference to the drawings.

As described above, in FIG. 32, it is indispensable to form the ridge portion 31A for current injection in the low dislocation density region of the stacked body 30 in order to improve the characteristics of the semiconductor laser device.

FIG. 36 (a) shows an example of a plurality of ridges 31 suitable for current injection. The ridge portion 31 marked with a circle is located between the convex portion 12a and the joint portion 14a, and is located in a region having the lowest dislocation density. On the contrary, the ridge portion 31 marked with a cross
Are located on the high dislocation density region.

Therefore, in the etching step for exposing the n-type contact layer 15 shown in FIG. 35, it is necessary to leave the ridge 31 marked with a circle as the ridge 31A for current injection.

Therefore, in the present embodiment, FIG.
As shown in (b), the following method is adopted so that the ridge portion 31A and the dummy ridge portion 31B can be easily and reliably selected.

[0312] A number or the like is assigned in advance so that the ridge portion 31A having the second formation period (pattern B) and the dummy ridge portion 31B can be distinguished. Here, the ridge 31 numbered 2 is replaced with the ridge 31A for current injection.
And

On the other hand, an alignment mark (= alignment pattern) is formed on the wafer, for example, in a cleaved region between laser elements on the substrate 11 so as to correspond to the number assigned to each ridge portion 31. It is provided. In the case of the present embodiment, the difference between the first formation period (pattern A) and the second formation period (pattern B) is 2 μm.
1 and the convex portion 12a have the same positional relationship with each other. Therefore, if at least eight alignment marks are prepared, the ridge 31 can be marked with a circle between the numbers 1 to 8.
At least one exists.

Therefore, in the etching step shown in FIG. 35, as an example, the boundary of the photomask is aligned with the region between the dummy ridge portion 31B of No. 3 and the dummy ridge portion 31B of No. 4 in the stacked body 30. Thus, the ridge portion 31A for current injection can be left.

Further, the ridge 31A numbered 2 can be easily recognized also in the etching for forming an opening in the insulating film 22 when the p-side electrode 23 is formed.

The chip width of the laser device is about 300 μm.
Since the length is m to 500 μm, the third cycle of numbers 1 to 8 appears not once but two or three times.

[0317] Further, the effect of the formation of the stripe-shaped voids 12c between the seed layer 12 and the selective growth layer 14 at the time of mask alignment will be described. This effect is caused by using the top surface of the convex portion 12a between the void portions 12c provided on the seed layer 12 as a seed crystal for ELO growth. That is, in order to select the ridge portion 31 having few dislocations, it is necessary to be able to identify a low dislocation density region in the stacked body 30 when observing from above using an optical microscope or the like. In the present embodiment, as shown in FIG.
Since the difference in the refractive index of the observation light increases, the position of the convex portion 12a (high dislocation density region) becomes clear, and therefore the ridge portion 31 for current injection located between the convex portion 12a and the joint portion 14a.
The ridge portion 31 that is a candidate for A can be easily and reliably distinguished. As a result, the alignment of the mask in the photolithography process is facilitated, and the throughput of the photolithography process can be improved.

In the present embodiment, the protrusion 12a
Although the first formation cycle and the second formation cycle of the ridge portion 31 are both constant, they need not always be constant, and may have any configuration as long as the formation cycles are shifted from each other. For example, a sequence group may be configured such that each formation cycle satisfies the arithmetic series.

Also, aluminum nitride is used for the insulating film 35 and silicon nitride is used for the insulating film 22.
It is sufficient that the etching selectivity is sufficiently large with respect to the insulating film 35 at the time of the etching. Instead, for example, the insulating film 35 may be silicon oxide and the insulating film 22 may be silicon nitride. Further, the etching for the insulating film 22 may be wet etching or dry etching.

[0320] Although sapphire was used for the substrate 11,
Instead of sapphire, for example, silicon carbide, neodymium gallate (NGO), gallium nitride, or the like may be used.

The mask film 13 may be made of a dielectric such as silicon nitride or silicon oxide by ECR sputtering, and more preferably, a high melting point metal such as tungsten or a silicide thereof.

Further, although the lift-off method is used when forming the projection 12a on the seed layer 12, any method can be used as long as the projection 12a and the groove 12b can be formed.

The method using two types of periodic structures having different periods from each other according to this embodiment is the same as the conventional ELO.
It can be applied to a growth method and the like.

[0324]

According to the method for manufacturing a nitride semiconductor of the present invention, the selective growth layer on which the ELO is grown is not affected by the polycrystalline material deposited on the mask film during the ELO growth. The quality of the crystal of the laminate grown thereon is improved. Therefore, the operating characteristics and reliability of the nitride semiconductor device using the nitride semiconductor of the present invention can be improved.

Further, a light confinement coefficient value can be improved by a void portion having a wall surface between the convex portions so as not to be affected by the polycrystal deposited on the mask film.

By providing the gap, the cavity end face can be formed naturally, and the cavity end face does not need to be a cleavage plane. Further, the tilt of the crystal growth axis of the selective growth layer can be reduced, and the mask Positioning can be easily performed.

[Brief description of the drawings]

FIG. 1 is a configuration sectional view showing a gallium nitride based semiconductor laser device according to a first embodiment of the present invention.

FIGS. 2A and 2B are cross-sectional views illustrating a method of manufacturing the gallium nitride-based semiconductor laser device according to the first embodiment of the present invention in the order of steps.

FIGS. 3A and 3B are cross-sectional views illustrating a method of manufacturing the gallium nitride based semiconductor laser device according to the first embodiment of the present invention in the order of steps.

FIG. 4 is a sectional view illustrating a method of manufacturing the gallium nitride based semiconductor laser device according to the first embodiment of the present invention in the order of steps.

FIG. 5 is a schematic cross-sectional view showing the features of the method for manufacturing the gallium nitride based semiconductor laser device according to the first embodiment of the present invention.

FIGS. 6A to 6D are schematic cross-sectional views illustrating the features of the method for manufacturing the gallium nitride based semiconductor laser device according to the first embodiment of the present invention step by step.

FIG. 7 is a graph showing a result of comparing photoluminescence at room temperature of a selective growth layer of a gallium nitride based semiconductor laser device according to a first modification of the first embodiment of the present invention with that of the first embodiment; .

FIG. 8 is a configuration sectional view showing a gallium nitride based semiconductor laser device according to a second modification of the first embodiment of the present invention.

FIG. 9 is a sectional view showing a configuration of a gallium nitride based semiconductor laser device according to a second embodiment of the present invention.

FIGS. 10A and 10B are cross-sectional views illustrating a method of manufacturing a gallium nitride based semiconductor laser device according to a second embodiment of the present invention in the order of steps.

FIG. 11 is a sectional view illustrating a method of manufacturing a gallium nitride-based semiconductor laser device according to a second embodiment of the present invention in the order of steps.

FIG. 12 is a sectional view illustrating a method of manufacturing a gallium nitride-based semiconductor laser device according to a second embodiment of the present invention in the order of steps.

FIG. 13 is a graph showing a far-field image of a laser beam emitted from a gallium nitride based semiconductor laser device according to a second embodiment of the present invention in a direction parallel to the cavity facet.

FIG. 14 is a configuration sectional view showing a gallium nitride based semiconductor laser device according to a third embodiment of the present invention.

FIG. 15 is a graph showing a relationship between a refractive index distribution in a direction perpendicular to a substrate at a ridge portion of a gallium nitride based semiconductor laser device according to a third embodiment of the present invention and a light intensity distribution on a cavity facet. .

FIG. 16 is a graph showing a far-field image of a laser beam emitted from a gallium nitride based semiconductor laser device according to a third embodiment of the present invention in a direction parallel to a cavity facet.

17A and 17B are a plan view photograph of a selectively grown layer of a gallium nitride based semiconductor laser device according to a third embodiment of the present invention before a laminate 30 is formed, taken by an optical microscope, and a corresponding cross-sectional view.

FIG. 18 is a sectional view showing a configuration of a gallium nitride based semiconductor laser device according to a fourth embodiment of the present invention.

FIG. 19A is a cross-sectional configuration diagram schematically showing a selective growth mechanism in a method for manufacturing a gallium nitride based semiconductor laser device according to a fourth embodiment of the present invention. FIG. 4B is a cross-sectional view schematically showing a selective growth mechanism in a method of manufacturing a gallium nitride based semiconductor laser device according to a second conventional example.

FIG. 20 (a) is a partial perspective view showing an effect of forming a selective growth layer in two stages in a method of manufacturing a gallium nitride based semiconductor laser device according to a fourth embodiment of the present invention. FIG. 2B is a partial perspective view showing a state in which undulation occurs on a side surface of the selective growth layer of the gallium nitride based semiconductor laser device for comparison.

FIGS. 21 (a) to (d) are schematic sectional views showing step by step the features of a method of manufacturing a gallium nitride based semiconductor laser device according to a fourth embodiment of the present invention.

FIG. 22 is a cross-sectional view of the structure of the gallium nitride-based semiconductor laser device according to a fifth embodiment of the present invention on the M-plane of the stacked body, that is, the A-plane of the substrate.

23 shows a gallium nitride based semiconductor laser device according to a fifth embodiment of the present invention, and is a cross-sectional view taken along line XXIII-XXIII of FIG.

FIG. 24 is a cross-sectional view of a stacked body in a gallium nitride based semiconductor laser device according to a first modification of the fifth embodiment of the present invention;
FIG. 2 is a cross-sectional view illustrating a configuration on a surface, that is, an A surface of the substrate.

FIG. 25 is a cross-sectional view of a gallium nitride based semiconductor laser device according to a second modification of the fifth embodiment of the present invention;
FIG. 2 is a cross-sectional view illustrating a configuration on a surface, that is, an A surface of the substrate.

FIG. 26 is a cross-sectional view of a gallium nitride based semiconductor laser device according to a third modification of the fifth embodiment of the present invention;
FIG. 2 is a cross-sectional view illustrating a configuration on a surface, that is, an A surface of the substrate.

FIG. 27 is a cross-sectional view of the structure of the gallium nitride-based semiconductor laser device according to a sixth embodiment of the present invention, taken along plane A of the stacked body, that is, plane M of the substrate.

FIGS. 28A and 28B are cross-sectional views in the order of steps showing a method for manufacturing a gallium nitride based semiconductor laser device according to a sixth embodiment of the present invention.

FIGS. 29A and 29B are cross-sectional views in the order of steps showing a method for manufacturing a gallium nitride based semiconductor laser device according to a sixth embodiment of the present invention.

FIGS. 30A and 30B are cross-sectional views in the order of steps showing a method for manufacturing a gallium nitride based semiconductor laser device according to a sixth embodiment of the present invention.

FIG. 31 is a sectional view illustrating a method of manufacturing a gallium nitride-based semiconductor laser device according to a sixth embodiment of the present invention in the order of steps.

FIG. 32 is a configuration sectional view of a gallium nitride based semiconductor laser device according to a seventh embodiment of the present invention.

FIG. 33 is a sectional view illustrating a method of manufacturing a gallium nitride based semiconductor laser device according to a seventh embodiment of the present invention in the order of steps.

FIG. 34 is a sectional view illustrating a method of manufacturing a gallium nitride based semiconductor laser device according to a seventh embodiment of the present invention in the order of steps.

FIG. 35 is a sectional view illustrating a method of manufacturing a gallium nitride-based semiconductor laser device according to a seventh embodiment of the present invention in the order of steps.

FIGS. 36A and 36B show a method of manufacturing a gallium nitride based semiconductor laser device according to a seventh embodiment of the present invention, and FIG. It is sectional drawing which shows a suitable ridge part, (b) is sectional drawing which shows a mode that the mark for identification is periodically attached to every ridge part.

FIG. 37 is a sectional view showing a configuration of a gallium nitride based semiconductor laser device according to a first conventional example.

FIG. 38 shows the crystal dislocations of gallium nitride formed by the ELOG method according to the second conventional example.

FIG. 39 is a sectional view showing the configuration of a gallium nitride based semiconductor laser device according to a second conventional example. FIG. 3 is a configuration sectional view schematically showing a distribution.

FIGS. 40A to 40D are schematic cross-sectional views showing steps of crystal growth in a method of manufacturing a gallium nitride based semiconductor laser device according to a second conventional example.

FIG. 41 is a graph showing a relationship between a refractive index distribution in a direction perpendicular to a substrate in a ridge portion of a gallium nitride based semiconductor laser device according to a first conventional example and a light intensity distribution on a cavity facet.

FIG. 42 shows a far-field image of a gallium nitride based semiconductor laser device according to a first conventional example.

FIG. 43 is a schematic perspective view showing a cleaved end face of a substrate and a resonator in a gallium nitride based laser device according to a first conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Substrate 11A Substrate 11A Convex part 11b Groove part 12 Seed layer 12a Convex part 12b Concave part (groove part) 12c Void part 13 Mask film 14 Selective growth layer 14a Junction part 14b High dislocation density region 14c Low dislocation density region 14d Wound 14A Selective growth layer 14B First selective growth layer 14C Second selective growth layer 15 n-type contact layer 15a junction 15A n-type superlattice contact layer 16 n-type clad layer 16A n-type superlattice clad layer 17 n-type optical guide layer 18 multiple quantum well (MQW) Active layer 19 p-type optical guide layer 20 p-type cladding layer 21 p-type contact layer 22 insulating film 23 p-side electrode 24 n-side electrode 25 p-side wiring electrode 26 n-side wiring electrode 30 laminated body 31 ridge portion 31A ridge Section 31B Dummy ridge section 32 Resonator end face 34 Selective growth seed layer 35 Insulation 40 a resist pattern 41 polycrystals

 ──────────────────────────────────────────────────続 き Continued on the front page (31) Priority claim number Japanese Patent Application No. 2000-18407 (P2000-18407) (32) Priority date January 27, 2000 (2000.1.127) (33) Priority claim country Japan (JP) (31) Priority claim number Japanese Patent Application No. 2000-25931 (P2000-25931) (32) Priority date February 3, 2000 (2000.2.3) (33) Priority claim country Japan (JP) (31) Priority claim number Japanese Patent Application No. 2000-48824 (P2000-48824) (32) Priority date February 25, 2000 (2000.2.25) (33) Priority claim country Japan (JP) (31) ) Priority claim number Japanese Patent Application No. 2000-120760 (P2000-120760) (32) Priority date April 21, 2000 (2000.4.21) (33) Priority claim country Japan (JP) (31) Priority Claim No. Japanese Patent Application No. 2000-120762 (P2000-120761) (32) Priority Date April 21, 2000 (2000.4.21) (33) Priority Country Japan (JP) (72) Inventor Takeshi Sugawara Osaka Prefecture 1006 Kadoma, Kadoma City Matsushita Electric Industrial Co., Ltd. (72) Inventor Ayumu Tsujimura 1006 Kadoma Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. Inside Sangyo Co., Ltd. (72) Inventor Masakatsu Suzuki 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Masahiro Kume 1006 Okadoma Kadoma, Osaka Pref. Person Yoshiko Miyanaga 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture, Japan Matsushita Electric Industrial Co., Ltd. 1006 Oaza Kadoma Matsushita Electric Industrial Co., Ltd.F-term (reference) AA13 AA 45 AA55 AA74 CA07 CB05 CB07 DA05 DA07 DA35 EA29

Claims (111)

[Claims] To 1. A _{substrate, Al u Ga v In w N} ( where, u, v, w is, 0 ≦ u, v, w ≦ 1, u + v + w =
It is one. A) forming a first nitride semiconductor layer comprising: forming a plurality of protrusions extending above the first nitride semiconductor layer at a distance from each other in a substrate surface direction; Forming a mask film covering a bottom surface of the concave portion sandwiched between the convex portions, and a top surface of each convex portion exposed from the mask film on the first nitride semiconductor layer. Using the C plane as a seed crystal, A
l _x Ga _y In _z N (where, x, y, z are, 0 ≦ x,
y, z ≦ 1, x + y + z = 1. A) growing a second nitride semiconductor layer comprising: 2. The method according to claim 1, wherein the mask film is made of a dielectric. 3. The nitride according to claim 2, wherein the dielectric is silicon nitride, silicon oxide, silicon oxynitride, aluminum oxide, aluminum nitride oxide, titanium oxide, zirconium oxide or niobium oxide. Semiconductor manufacturing method. 4. The method according to claim 1, wherein the mask film is made of a refractory metal or a refractory metal. 5. The refractory metal or refractory metal,
The method for producing a nitride semiconductor according to claim 4, wherein the method is tungsten, molybdenum, niobium, tungsten silicide, molybdenum silicide, or niobium silicide. 6. A _{substrate, Al u Ga v In w N} ( where, u, v, w is, 0 ≦ u, v, w ≦ 1, u + v + w =
It is one. A) forming a first nitride semiconductor layer comprising: forming a plurality of protrusions extending above the first nitride semiconductor layer at a distance from each other in a substrate surface direction; Forming a mask film covering a bottom surface of the concave portion sandwiched between the convex portions and at least a part of the wall surface; and forming the mask in each of the convex portions on the first nitride semiconductor layer. A region exposed from the film is used as a seed crystal, and Al _x
Ga _y In _z N (where x, y, z are 0 ≦ x, y, z
≦ 1, x + y + z = 1. A) growing a second nitride semiconductor layer comprising: 7. The method according to claim 6, wherein the mask film is made of a dielectric. 8. The nitride according to claim 7, wherein the dielectric is silicon nitride, silicon oxide, silicon oxynitride, aluminum oxide, aluminum nitride oxide, titanium oxide, zirconium oxide or niobium oxide. Semiconductor manufacturing method. 9. The method according to claim 6, wherein the mask film is made of a refractory metal or a refractory metal. 10. The method according to claim 9, wherein the refractory metal or refractory metal is tungsten, molybdenum, niobium, tungsten silicide, molybdenum silicide or niobium silicide. 11. A step of forming a first nitride semiconductor layer on a substrate, and a step of forming a plurality of trenches extending above the first nitride semiconductor layer at intervals from one another in a substrate surface direction. Forming a mask film covering the bottom surface of the trench; and forming a C-plane exposed from the mask film between the trenches on the upper surface of the first nitride semiconductor layer as a seed crystal from the substrate side. An active layer composed of a second nitride semiconductor layer, a third nitride semiconductor layer having an energy gap smaller than that of the second nitride semiconductor layer, and a fourth nitride layer having an energy gap larger than that of the active layer. And a step of forming a current confinement section for selectively injecting carriers into the active layer, on the layered body. Of nitride semiconductor devices Method. 12. The step of forming the plurality of trenches includes forming a resist mask covering the first nitride semiconductor layer in a stripe shape on the first nitride semiconductor layer, and forming the resist mask 12. The method according to claim 11, further comprising the step of: etching the first nitride semiconductor layer by using a mask; and the step of forming the mask film includes a step of lifting off the resist mask.
3. The method for manufacturing a nitride semiconductor device according to item 1. 13. The method according to claim 11, wherein the mask film is made of a dielectric. 14. The nitride according to claim 13, wherein the dielectric is silicon nitride, silicon oxide, silicon oxynitride, aluminum oxide, aluminum nitride oxide, titanium oxide, zirconium oxide or niobium oxide. A method for manufacturing a semiconductor device. 15. The method according to claim 13, wherein the mask film is formed using electron cyclotron resonance plasma. 16. The method according to claim 13, wherein the mask film is formed by using an electron cyclotron resonance sputtering method. 17. The method according to claim 11, wherein the mask film is made of a refractory metal or a refractory metal. 18. The method according to claim 17, wherein the refractory metal or refractory metal is tungsten, molybdenum, niobium, tungsten silicide, molybdenum silicide or niobium silicide. . 19. A step of forming a first nitride semiconductor layer on a substrate, and a step of forming a plurality of grooves extending at an interval in a substrate surface direction above the first nitride semiconductor layer. Forming a mask film covering a bottom surface of the groove and at least a part of the wall surface; and forming a region exposed from the mask film between the grooves on the first nitride semiconductor layer. As a seed crystal,
From the substrate side, a second nitride semiconductor layer, an active layer including a third nitride semiconductor layer having an energy gap smaller than that of the second nitride semiconductor layer, and an active layer having an energy gap larger than that of the active layer. A step of growing a stacked body to include the nitride semiconductor layer of No. 4, and a step of forming a current constriction on the stacked body to selectively inject carriers into the active layer. A method for manufacturing a nitride semiconductor device, comprising: 20. The step of forming the plurality of trenches, comprising: forming a resist mask on the first nitride semiconductor layer so as to cover the first nitride semiconductor layer in a stripe shape; 20. The method according to claim 19, further comprising: performing a step of etching the first nitride semiconductor layer by using a semiconductor device; and forming the mask film includes a step of lifting off the resist mask.
3. The method for manufacturing a nitride semiconductor device according to item 1. 21. The method according to claim 19, wherein the mask film is made of a dielectric. 22. The nitride according to claim 21, wherein the dielectric is silicon nitride, silicon oxide, silicon oxynitride, aluminum oxide, aluminum nitride oxide, titanium oxide, zirconium oxide or niobium oxide. Semiconductor manufacturing method. 23. The method according to claim 21, wherein the mask film is formed using electron cyclotron resonance plasma. 24. The method according to claim 21, wherein the mask film is formed by using an electron cyclotron resonance sputtering method. 25. The method according to claim 19, wherein the mask film is made of a refractory metal or a refractory metal. 26. The method according to claim 25, wherein the refractory metal or refractory metal is tungsten, molybdenum, niobium, tungsten silicide, molybdenum silicide or niobium silicide. . To 27. The upper substrate, forming a plurality of protrusions extending in parallel to each other in the substrate plane direction, the top surface of each protrusion over said substrate, Al _x Ga _y In
_z N (where x, y, and z are 0 ≦ x, y, z ≦ 1, x +
y + z = 1. A step of selectively growing a nitride semiconductor layer comprising: 28. The method according to claim 28, wherein the substrate is made of a nitride semiconductor. Between the step of forming the protrusion and the step of growing the nitride semiconductor layer, the recess formed between the protrusions adjacent to each other is formed. The method for manufacturing a nitride semiconductor according to claim 27, further comprising a step of forming a mask film made of a dielectric, a high-melting metal or a high-melting metal, which covers the bottom surface. 29. A step of forming a plurality of grooves extending apart from each other in a substrate surface direction on an upper portion of a substrate; and selectively forming a plurality of grooves on the upper surface of the substrate between the respective grooves from the substrate side. An active layer composed of a first nitride semiconductor layer, a second nitride semiconductor layer having an energy gap smaller than that of the first nitride semiconductor layer, and a third nitride layer having an energy gap larger than that of the active layer. A step of growing a stacked body so as to include a nitride semiconductor layer; and a step of forming a current constriction on the stacked body to selectively inject carriers into the active layer. Manufacturing method of a nitride semiconductor device. 30. The step of growing the stacked body includes a step of forming a plurality of voids surrounded by a bottom surface and a wall surface of each of the groove portions, and a surface of the stacked body opposed to the groove portion. The method for manufacturing a semiconductor device according to claim 29, wherein: 31. The method according to claim 29, wherein, in the step of growing the stacked body, the stacked body is grown on the substrate without interposing a buffer layer. 32. An active layer comprising a first nitride semiconductor layer, a second nitride semiconductor layer having a higher refractive index of light than the first nitride semiconductor layer, sequentially formed on a substrate, and an active layer comprising the first nitride semiconductor layer. A laminate including a third nitride semiconductor layer having a smaller refractive index of light than the layer; and a current constriction portion formed on the laminate and selectively injecting carriers into the active layer. A nitride semiconductor device, wherein a void portion is formed in the active layer below the current constriction portion and in a region between the active layer and the substrate. 33. A fourth nitride semiconductor layer having a refractive index smaller than or equal to the refractive index of light of the first nitride semiconductor layer is formed on the gap. 33. The nitride semiconductor device according to claim 32, wherein: 34. A first nitride semiconductor layer formed on a substrate and having a plurality of projections extending in the direction of the substrate surface at an interval from each other on the substrate, and on the first nitride semiconductor layer: A second nitride semiconductor layer formed so that a lower surface thereof is in contact with a top surface of each of the protrusions; a third nitride semiconductor layer formed on the second nitride semiconductor layer; A stacked body including an active layer made of a fourth nitride semiconductor layer having a higher refractive index of light than the nitride semiconductor layer of (a) and a fifth nitride semiconductor layer having a smaller refractive index of light than the active layer. The nitride semiconductor element, wherein the second nitride semiconductor layer has a refractive index smaller than or equal to the refractive index of light of the third nitride semiconductor layer. 35. The semiconductor device according to claim 35, further comprising a low-refractive-index region formed between the convex portions and having a refractive index smaller than a refractive index of light of the second nitride semiconductor layer. Item 35. The nitride semiconductor device according to item 34. 36. The nitride semiconductor device according to claim 35, wherein the low refractive index region is a void. 37. The second nitride semiconductor layer and the third nitride semiconductor layer
Having a superlattice structure formed between the second nitride semiconductor layer and the third nitride semiconductor layer and having a refractive index smaller than or equal to the refractive index of light of the second nitride semiconductor layer or the third nitride semiconductor layer. ,
35. The nitride semiconductor device according to claim 34, further comprising a sixth nitride semiconductor layer whose upper surface is in contact with the electrode. 38. The second nitride semiconductor layer contains aluminum in a composition, and each of the protrusions is provided between the first nitride semiconductor layer and the second nitride semiconductor layer. A plurality of sixth nitride semiconductor layers formed so as to cover only the top surface of the second nitride semiconductor layer and the vicinity thereof and having an aluminum composition smaller than the aluminum composition of the second nitride semiconductor layer. 35. The nitride semiconductor device according to claim 34, wherein: 39. A step of forming a first nitride semiconductor layer on a substrate, and a step of forming a plurality of trenches extending above the first nitride semiconductor layer at intervals from one another in a substrate surface direction. Forming a mask film covering the bottom surface of the trench; and forming a C-plane exposed from the mask film between the trenches on the upper surface of the first nitride semiconductor layer as a seed crystal from the substrate side. An active layer including a second nitride semiconductor layer, a third nitride semiconductor layer, a fourth nitride semiconductor layer having a higher refractive index of light than the third nitride semiconductor layer, Growing a laminate so as to include a fifth nitride semiconductor layer having a smaller refractive index of light than the layer; and a current confinement portion for selectively injecting carriers into the active layer on the laminate. Forming the stacked body, wherein the step of growing the stacked body comprises: A step of growing the second nitride semiconductor layer such that the refractive index of the light is smaller than or equal to the refractive index of the light of the third nitride semiconductor layer. Device manufacturing method. 40. The step of growing the stacked body, the method comprising: when the composition of the second nitride semiconductor layer includes aluminum, forming the second nitride semiconductor layer between the first nitride semiconductor layer and the second nitride semiconductor layer. Forming a plurality of sixth nitride semiconductor layers in which the composition of aluminum is smaller than the aluminum composition of the second nitride semiconductor layer so as to cover only the top surface of the protrusion and the vicinity thereof 40. The method of claim 39, comprising:
3. The method for manufacturing a nitride semiconductor device according to item 1. 41. The step of growing the stacked body, wherein the second nitride semiconductor layer or the third nitride layer is disposed between the second nitride semiconductor layer and the third nitride semiconductor layer. 40. The nitride according to claim 39, further comprising a step of forming a sixth nitride semiconductor layer having a superlattice structure having a refractive index smaller than or equal to the refractive index of light of the semiconductor layer. A method for manufacturing a semiconductor device. 42. A step of forming the plurality of trenches, comprising: forming a resist mask on the first nitride semiconductor layer to cover the first nitride semiconductor layer in a stripe shape; 40. The method according to claim 39, further comprising: performing a step of etching the first nitride semiconductor layer using the first method; and a step of forming the mask film includes a step of lifting off the resist mask.
3. The method for manufacturing a nitride semiconductor device according to item 1. 43. The method according to claim 39, wherein the mask film is made of a dielectric. 44. The nitride according to claim 43, wherein the dielectric is silicon nitride, silicon oxide, silicon oxynitride, aluminum oxide, aluminum nitride oxide, titanium oxide, zirconium oxide or niobium oxide. A method for manufacturing a semiconductor device. 45. The method according to claim 43, wherein the mask film is formed using electron cyclotron resonance plasma. 46. The method according to claim 43, wherein the mask film is formed by using an electron cyclotron resonance sputtering method. 47. The method according to claim 39, wherein the mask film is made of a refractory metal or a refractory metal. 48. The method according to claim 47, wherein the refractory metal or refractory metal is tungsten, molybdenum, niobium, tungsten silicide, molybdenum silicide or niobium silicide. . 49. A step of forming a first nitride semiconductor layer on a substrate, and a step of forming a plurality of trenches extending above the first nitride semiconductor layer at intervals from each other in a substrate surface direction. Forming a mask film covering a bottom surface of the groove and at least a part of the wall surface; and forming a region exposed from the mask film between the grooves on the first nitride semiconductor layer. As a seed crystal,
From the substrate side, a second nitride semiconductor layer, a third nitride semiconductor layer, and an active layer including a fourth nitride semiconductor layer having a higher refractive index of light than the third nitride semiconductor layer. Growing a laminate so as to include a fifth nitride semiconductor layer having a smaller refractive index of light than the active layer; and selectively injecting carriers into the active layer on the laminate. Forming a current confined portion, wherein the step of growing the stacked body includes the step of forming the second nitride semiconductor layer such that a refractive index of light of the second nitride semiconductor layer is higher than a refractive index of light of the third nitride semiconductor layer. A process for growing the nitride semiconductor device so that the size is also small or equivalent. 50. The step of growing the stacked body, the method comprising: when the composition of the second nitride semiconductor layer includes aluminum, the step of forming the first nitride semiconductor layer and the second nitride semiconductor layer Forming a plurality of sixth nitride semiconductor layers in which the composition of aluminum is smaller than the aluminum composition of the second nitride semiconductor layer so as to cover only the top surface of the protrusion and the vicinity thereof 50. The method of claim 49, comprising:
3. The method for manufacturing a nitride semiconductor device according to item 1. 51. The step of growing the stacked body, wherein the second nitride semiconductor layer or the third nitride semiconductor layer is provided between the second nitride semiconductor layer and the third nitride semiconductor layer. 50. The nitride according to claim 49, further comprising a step of forming a sixth nitride semiconductor layer having a superlattice structure having a refractive index smaller than or equal to the refractive index of light of the semiconductor layer. A method for manufacturing a semiconductor device. 52. The step of forming the plurality of trenches includes forming a resist mask on the first nitride semiconductor layer, the resist mask covering the first nitride semiconductor layer in a stripe shape, and forming the resist mask on the first nitride semiconductor layer. 50. The method according to claim 49, further comprising: performing a step of etching the first nitride semiconductor layer by using a semiconductor device; and forming the mask film includes a step of lifting off the resist mask.
3. The method for manufacturing a nitride semiconductor device according to item 1. 53. The method according to claim 49, wherein the mask film is made of a dielectric. 54. The nitride according to claim 53, wherein the dielectric is silicon nitride, silicon oxide, silicon oxynitride, aluminum oxide, aluminum nitride oxide, titanium oxide, zirconium oxide or niobium oxide. A method for manufacturing a semiconductor device. 55. The method according to claim 53, wherein the mask film is formed using electron cyclotron resonance plasma. 56. The method according to claim 53, wherein the mask film is formed by using an electron cyclotron resonance sputtering method. 57. The method according to claim 49, wherein the mask film is made of a refractory metal or a refractory metal. 58. The method according to claim 57, wherein the refractory metal or refractory metal is tungsten, molybdenum, niobium, tungsten silicide, molybdenum silicide or niobium silicide. . To 59. A _{substrate, Al u Ga v In w N} ( where, u, v, w is, 0 ≦ u, v, w ≦ 1, u + v + w =
It is one. A) forming a first nitride semiconductor layer comprising: forming a plurality of protrusions extending above the first nitride semiconductor layer at a distance from each other in a substrate surface direction; Forming a mask film covering a bottom surface of the concave portion sandwiched between the convex portions, and a top surface of each convex portion exposed from the mask film on the first nitride semiconductor layer. Using the C plane as a seed crystal, A
l _x Ga _y In _z N (where, x, y, z are, 0 ≦ x,
y, z ≦ 1, x + y + z = 1. A) growing a plurality of second nitride semiconductor layers comprising: forming the plurality of second nitride semiconductor layers; Each time the nitride semiconductor layer straddles a predetermined number of protrusions of the plurality of protrusions,
A method for manufacturing a nitride semiconductor, comprising a step of forming a side end surface parallel to a direction in which the protrusion extends. 60. The method for manufacturing a nitride semiconductor according to claim 59, wherein said side end surface is an A plane or an M plane. 61. The step of forming the plurality of protrusions, wherein the formation period of the plurality of protrusions is formed such that a region where the side end surface is exposed is larger than a region where the side end surface is not exposed. 60. The method for producing a nitride semiconductor according to claim 59, wherein: 62. The method according to claim 59, wherein the mask film is made of a dielectric. 63. The nitride according to claim 62, wherein the dielectric is silicon nitride, silicon oxide, silicon oxynitride, aluminum oxide, aluminum nitride oxide, titanium oxide, zirconium oxide or niobium oxide. Semiconductor manufacturing method. 64. The method according to claim 59, wherein the mask film is made of a refractory metal or a refractory metal. 65. The method according to claim 64, wherein the refractory metal or refractory metal is tungsten, molybdenum, niobium, tungsten silicide, molybdenum silicide, or niobium silicide. To 66. on a _{substrate, Al u Ga v In w N} ( where, u, v, w is, 0 ≦ u, v, w ≦ 1, u + v + w =
It is one. A) forming a first nitride semiconductor layer comprising: forming a plurality of protrusions extending above the first nitride semiconductor layer at a distance from each other in a substrate surface direction; Forming a mask film covering a bottom surface of the concave portion sandwiched between the convex portions and at least a part of the wall surface; and forming the mask in each of the convex portions on the first nitride semiconductor layer. A region exposed from the film is used as a seed crystal, and Al _x
Ga _y In _z N (where x, y, z are 0 ≦ x, y, z
≦ 1, x + y + z = 1. A) growing a plurality of second nitride semiconductor layers comprising: forming the plurality of second nitride semiconductor layers; Each time the nitride semiconductor layer straddles a predetermined number of protrusions of the plurality of protrusions,
A method for manufacturing a nitride semiconductor, comprising a step of forming a side end surface parallel to a direction in which the protrusion extends. 67. The method according to claim 66, wherein the side end surface is an A-plane or an M-plane. 68. In the step of forming the plurality of protrusions, the formation period of the plurality of protrusions is formed such that a region where the side end surface is exposed is larger than a region where the side end surface is not exposed. The method for producing a nitride semiconductor according to claim 66, wherein: 69. The method according to claim 66, wherein the mask film is made of a dielectric. 70. The nitride according to claim 69, wherein the dielectric is silicon nitride, silicon oxide, silicon oxynitride, aluminum oxide, aluminum nitride oxide, titanium oxide, zirconium oxide or niobium oxide. Semiconductor manufacturing method. 71. The method according to claim 66, wherein the mask film is made of a refractory metal or a refractory metal. 72. The method according to claim 71, wherein the refractory metal or refractory metal is tungsten, molybdenum, niobium, tungsten silicide, molybdenum silicide, or niobium silicide. 73. A step of forming a first nitride semiconductor layer on a substrate, and a step of forming a plurality of trenches extending above the first nitride semiconductor layer at intervals from each other in a substrate surface direction. Forming a mask film covering the bottom surface of the trench; and forming a C-plane exposed from the mask film between the trenches on the upper surface of the first nitride semiconductor layer as a seed crystal from the substrate side. An active layer including a second nitride semiconductor layer, a third nitride semiconductor layer having an energy gap smaller than the second nitride semiconductor layer, and a third nitride semiconductor layer having an energy gap larger than the active layer. A step of growing a plurality of stacked bodies so as to include the nitride semiconductor layer of No. 4; and a step of forming a current confinement portion for selectively injecting carriers into the active layer on each of the stacked bodies. Comprising, the plurality of products Growing a body, each of said laminate,
A step of forming the laminated body so as to expose a cavity end face formed of the current constriction portion every time the predetermined number of straddles the C-plane of the first nitride semiconductor layer. Device manufacturing method. 74. The method according to claim 73, wherein the end face of the resonator is an A-plane or an M-plane. 75. The step of forming the plurality of grooves, wherein the forming cycle of the plurality of grooves is set such that a region where the resonator end face is exposed is larger than a region where the resonator end face is not exposed. 74. The method for manufacturing a nitride semiconductor device according to claim 73, wherein: 76. The method according to claim 73, wherein the mask film is made of a dielectric. 77. The nitride according to claim 76, wherein the dielectric is silicon nitride, silicon oxide, silicon oxynitride, aluminum oxide, aluminum nitride oxide, titanium oxide, zirconium oxide or niobium oxide. A method for manufacturing a semiconductor device. 78. The method according to claim 73, wherein the mask film is made of a refractory metal or a refractory metal. 79. The method according to claim 78, wherein the refractory metal or refractory metal is tungsten, molybdenum, niobium, tungsten silicide, molybdenum silicide or niobium silicide. . 80. A step of forming a first nitride semiconductor layer on a substrate, and a step of forming a plurality of trenches extending above the first nitride semiconductor layer at intervals from each other in a substrate surface direction. Forming a mask film covering a bottom surface of the groove and at least a part of the wall surface; and forming a region exposed from the mask film between the grooves on the first nitride semiconductor layer. As a seed crystal,
From the substrate side, respectively, a second nitride semiconductor layer, an active layer composed of a third nitride semiconductor layer having an energy gap smaller than the second nitride semiconductor layer, and an energy gap smaller than the active layer. Growing a plurality of stacked bodies so as to include a fourth nitride semiconductor layer having a large thickness, and forming a current confinement portion for selectively injecting carriers into the active layer on each of the stacked bodies. And a step of growing the plurality of stacked bodies includes:
A step of forming the laminated body so that a cavity end face composed of the current confinement portion is exposed every time a predetermined number of regions cross over regions between adjacent trenches of the first nitride semiconductor layer. Manufacturing method of a nitride semiconductor device. 81. The method according to claim 80, wherein the end face of the resonator is an A-plane or an M-plane. 82. The step of forming the plurality of grooves, wherein the forming cycle of the plurality of grooves is set such that a region where the resonator end surface is exposed is larger than a region where the resonator end surface is not exposed. The method for manufacturing a nitride semiconductor device according to claim 80, wherein: 83. The method according to claim 80, wherein the mask film is made of a dielectric. 84. The nitride according to claim 83, wherein said dielectric is silicon nitride, silicon oxide, silicon oxynitride, aluminum oxide, aluminum nitride oxide, titanium oxide, zirconium oxide or niobium oxide. A method for manufacturing a semiconductor device. 85. The method according to claim 80, wherein the mask film is made of a refractory metal or a refractory metal. 86. The method according to claim 85, wherein the refractory metal or refractory metal is tungsten, molybdenum, niobium, tungsten silicide, molybdenum silicide or niobium silicide. . 87. A first nitride semiconductor layer formed on a substrate and having a plurality of protrusions extending in the direction of the substrate surface at an interval from each other on the substrate, and on the first nitride semiconductor layer and A second nitride semiconductor layer formed so as to have a gap between the side surfaces of the respective convex portions; and a second nitride semiconductor layer formed on the second nitride semiconductor layer, wherein carriers are narrowed and injected. Third including a striped resonator
Wherein the resonator is provided such that a resonance direction of generated light is substantially orthogonal to a direction in which the protrusion extends. 88. The nitride semiconductor device according to claim 87, wherein an end face of said resonator is an A-plane of said third nitride semiconductor layer. 89. The second nitride semiconductor layer and the third nitride semiconductor layer
Formed on the upper surface of the first nitride semiconductor layer, the upper surface extending in the direction of the substrate surface at an interval from each other, and the position of the top surface being the same as the position of the top surface of the projection of the first nitride semiconductor layer. 88. The nitride semiconductor device according to claim 87, further comprising a fourth nitride semiconductor layer having a plurality of convex portions different in directions. 90. A first nitride semiconductor layer formed on a substrate and having a plurality of protrusions extending upward in the direction of the substrate at intervals from each other on the substrate, and on the first nitride semiconductor layer and A second nitride semiconductor layer formed so as to have a gap between side surfaces of the respective convex portions; and a third nitride layer formed on the second nitride semiconductor layer and including an active layer. A top surface of the convex portion is a C-plane, and an angle formed by a C-axis of the first nitride semiconductor layer and a C-axis of the second nitride semiconductor layer is about 0. 0.55 degrees or less. 91. A step of forming a first nitride semiconductor layer on a substrate; and forming a plurality of first nitride semiconductor layers on the first nitride semiconductor layer that are spaced apart from each other and extend in one direction in a substrate plane direction. Forming a first groove portion; forming a first mask film covering a bottom surface of the first groove portion; and between the first groove portions on the upper surface of the first nitride semiconductor layer. Growing a second nitride semiconductor layer using the C-plane exposed from the first mask film as a seed crystal; and forming the one direction on the second nitride semiconductor layer at an interval from each other. Forming a plurality of second grooves that extend in the direction of the substrate and that are different from the position of the region between the first grooves in the direction of the surface of the substrate. Forming a second mask film covering the bottom surface of the second nitride film; Forming a third nitride semiconductor layer including an active layer using a C-plane exposed from the second mask film as a seed crystal between the second trenches on the upper surface of the conductor layer; Forming a current confinement portion on the nitride semiconductor layer of (3) such that the resonance direction of the generated light is substantially orthogonal to the one direction. . 92. A step of forming a first nitride semiconductor layer on a substrate; and forming a plurality of first nitride semiconductor layers on the first nitride semiconductor layer that are spaced apart from each other and extend in one direction in a substrate surface direction. Forming a first groove portion; forming a first mask film covering a bottom surface of the first groove portion and at least a part of a wall surface of the first groove portion; and forming each of the first mask films on the first nitride semiconductor layer. Growing a second nitride semiconductor layer between the first trenches using a region exposed from the first mask film as a seed crystal; and forming an interval above the second nitride semiconductor layer. Forming a plurality of second grooves extending in the one direction and having a position between regions adjacent to each other in a substrate surface direction different from a position between regions between the first grooves in a substrate surface direction And the bottom surface of the second groove and at least a part of the wall surface Forming a second mask film between the respective second trenches on the second nitride semiconductor layer, using a region exposed from the second mask film as a seed crystal, Forming a third nitride semiconductor layer including: and forming a current confinement portion on the third nitride semiconductor layer such that a resonance direction of generated light is substantially orthogonal to the one direction. And a method for manufacturing a nitride semiconductor device. 93. A first semiconductor layer formed on a substrate and having a plurality of first protrusions extending in the direction of the substrate surface at an interval above the first semiconductor layer, and the first semiconductor layer on the first semiconductor layer. And a plurality of second convex portions formed in the upper portion so as to be in contact with the first convex portions and extending at intervals different from the intervals between the first convex portions. A second semiconductor layer made of a stacked body including an active layer, wherein carriers are injected into the active layer from a top surface of one of the plurality of second protrusions. Semiconductor light emitting device. 94. forming a first semiconductor layer on a substrate,
Forming a plurality of first protrusions extending at an interval in a substrate surface direction on an upper portion of the formed first semiconductor layer; A second semiconductor layer made of a laminate including an active layer is formed in contact with the convex portion, and the first semiconductor portion is formed on the formed second semiconductor layer in the same direction as the direction in which the first convex portion extends. Forming a plurality of second protrusions extending at different intervals from the protrusions; and a mask for selecting a protrusion for injecting carriers into the active layer from among the plurality of second protrusions. Forming a mark for alignment on the substrate, and after positioning the mask with the mark,
Using the mask to make one of the plurality of second protrusions a carrier injection part. 95. The first semiconductor layer and the second semiconductor layer are made of a nitride semiconductor, and the step of forming the first protrusion is sandwiched between the formed first protrusions. Forming a dielectric film in a region where the mark is formed, wherein the step of forming the mark does not overlap the mark with the first convex portion in a direction perpendicular to the substrate surface and forms the mark with the first convex portion. The method for manufacturing a semiconductor light emitting device according to claim 94, further comprising a step of attaching the second convex portion located in the vicinity so as to be recognized. 96. A step of forming a first nitride semiconductor layer on a substrate, and a step of forming a plurality of trenches extending above the first nitride semiconductor layer at intervals from each other in a substrate surface direction. Forming a mask film covering the bottom surface of the trench; and forming a C-plane exposed from the mask film between the trenches on the upper surface of the first nitride semiconductor layer as a seed crystal from the substrate side. An active layer composed of a second nitride semiconductor layer, a third nitride semiconductor layer having an energy gap smaller than that of the second nitride semiconductor layer, and a fourth nitride layer having an energy gap larger than that of the active layer. Growing a laminate so as to include a semiconductor layer; and a plurality of protrusions extending on the top of the laminate at the same distance as the direction in which the grooves extend and different from the distance between the grooves. And forming the Forming a carrier injection portion for injecting carriers into the active layer by selecting a protrusion located above the groove and near a region between the grooves among the plurality of protrusions. A method for manufacturing a semiconductor light emitting device, comprising: 97. A step of forming the plurality of trenches, comprising: forming a resist mask over the first nitride semiconductor layer so as to cover the first nitride semiconductor layer in a stripe shape; 97. The method according to claim 96, further comprising: performing a step of etching the first nitride semiconductor layer by using a semiconductor device; and forming the mask film includes a step of lifting off the resist mask.
3. The method for manufacturing a semiconductor light emitting device according to 1. 98. The method according to claim 96, wherein the mask film is made of a dielectric. 99. The semiconductor light emitting device according to claim 98, wherein said dielectric is silicon nitride, silicon oxide, silicon oxynitride, aluminum oxide, aluminum nitride oxide, titanium oxide, zirconium oxide or niobium oxide. Device manufacturing method. 100. The method according to claim 98, wherein the mask film is formed using electron cyclotron resonance plasma. 101. The method according to claim 98, wherein the mask film is formed by using an electron cyclotron resonance sputtering method. 102. The method according to claim 96, wherein the mask film is made of a refractory metal or a refractory metal. 103. The method according to claim 102, wherein the refractory metal or refractory metal is tungsten, molybdenum, niobium, tungsten silicide, molybdenum silicide or niobium silicide. 104. A step of forming a first nitride semiconductor layer on a substrate, and a step of forming a plurality of trenches extending above the first nitride semiconductor layer at intervals from each other in a substrate surface direction. Forming a mask film covering a bottom surface of the groove and at least a part of the wall surface; and forming a region exposed from the mask film between the grooves on the first nitride semiconductor layer. As a seed crystal,
From the substrate side, a second nitride semiconductor layer, an active layer including a third nitride semiconductor layer having an energy gap smaller than that of the second nitride semiconductor layer, and an active layer having an energy gap larger than that of the active layer. Growing a laminate so as to include the nitride semiconductor layer of No. 4 and a plurality of trenches extending above the laminate at the same interval as the direction in which the grooves extend and different from the interval between the grooves. Forming a convex portion, and selecting, from the plurality of convex portions, a convex portion located above the groove portion and in the vicinity of a region between the groove portions, and forming the active layer on the selected convex portion. Forming a carrier injection portion for injecting carriers into the semiconductor light emitting device. 105. The step of forming the plurality of grooves,
Forming a resist mask covering the first nitride semiconductor layer in a stripe shape on the first nitride semiconductor layer, and etching the first nitride semiconductor layer using the formed resist mask; 11. The step of forming the mask film includes a step of lifting off the resist mask.
5. The method for manufacturing a semiconductor light emitting device according to item 4. 106. The method according to claim 104, wherein the mask film is made of a dielectric. 107. The semiconductor light emitting device according to claim 106, wherein said dielectric is silicon nitride, silicon oxide, silicon oxynitride, aluminum oxide, aluminum nitride oxide, titanium oxide, zirconium oxide or niobium oxide. Device manufacturing method. 108. The method according to claim 106, wherein the mask film is formed using electron cyclotron resonance plasma. 109. The method according to claim 106, wherein the mask film is formed by using an electron cyclotron resonance sputtering method. 110. The method according to claim 104, wherein the mask film is made of a high melting point metal or a high melting point metal. 111. The method according to claim 110, wherein the refractory metal or refractory metal is tungsten, molybdenum, niobium, tungsten silicide, molybdenum silicide or niobium silicide.