JP2002111128A - Semiconductor laser device and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser device which is excellent in efficiency and capable of projecting a laser beam with excellent properties and a method of manufacturing the same. SOLUTION: A semiconductor laser device is equipped with a first semiconductor including an active layer with a pair of resonant planes on a substrate, and a second semiconductor with an edge face which confronts the resonant planes and forms an angle with the horizontal direction of the substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor laser device having a member having an end face formed at an angle inclined with respect to a horizontal direction of a substrate and emitting laser light in a direction different from the horizontal direction of the substrate outside the resonance surface. In particular, the present invention relates to a laser device capable of extracting light with excellent beam characteristics with high efficiency and a method of forming a laser device capable of being formed with a relatively simple method with good mass productivity.

[0002]

2. Description of the Related Art In recent years, semiconductor lasers are small, lightweight,
Highly reliable and high-output personal computers
, DVDs and other electronic equipment, medical equipment, processing equipment and optical
It is used as a light source for fiber communication. Nitriding
Semiconductor (In _XAl_YGa_1-XYN, 0 ≦ X, 0 ≦ Y, X +
Y ≦ 1) can emit red to red from a relatively short wavelength ultraviolet region
Is attracting attention as a simple semiconductor laser device.

An example of such a semiconductor laser device is shown in FIG.
Shown in FIG. 5 is a schematic sectional view of a semiconductor laser device using a nitride semiconductor, which is an electrode stripe type laser device. An n-type contact layer, an n-type clad layer, an n-type light guide layer, an active layer, a p-type light guide layer, a p-type clad layer, and a p-type contact layer are sequentially formed on a sapphire substrate. Each semiconductor layer is partially etched until the n-type contact layer is exposed, and an electrode is formed on each contact layer. It also has a resonator in which a parallel mirror is formed on the end face of the active layer by etching, and a mirror that is outside the resonance face, the end face is composed of a plurality of layers, and has an angle inclined with respect to the horizontal direction of the substrate. ing.

A cavity facet of a semiconductor laser device can be formed relatively easily by utilizing cleavage of a semiconductor material. However, it is extremely difficult to form a resonator on a cleavage plane with good mass productivity when a substrate such as sapphire has a poor cleavage property or when the cleavage plane between the nitride semiconductor surface and the substrate is misaligned. Therefore, the end face of the resonator is formed by etching.

On the other hand, when the resonator end face is etched to form a resonance face, "etching margin" is created. The horizontal nitride semiconductor surface generated by the etching or the substrate surface becomes an excess portion and is exposed on the surface. This “etching margin” blocks a part of the laser light emitted from the end face of the active layer, so that the laser light cannot be focused and the output is reduced. In order to remove the etching margin, the substrate must be processed using many processes, and the yield is reduced because the process control is difficult.

Therefore, the substrate itself is processed in order to extract light by using a laser element in which a mirror outside the resonance surface and having an end surface inclined at an angle to the horizontal direction of the substrate is formed by etching. There is no need, and laser light can be easily focused by a relatively simple method, so that a high-output semiconductor laser can be obtained. Further, a semiconductor laser which can be highly integrated can be provided.

[0007]

However, with the expansion of the field of use, a semiconductor laser having a higher output and a higher condensing degree is required at present, and the semiconductor laser device having the above configuration is not sufficient, and further improvement is required. Have been. In particular, it is an object of the present invention to provide a laser device capable of easily condensing a laser beam, increasing a laser output, and achieving high integration, and a method of forming the same.

[0008]

According to a first aspect of the present invention, there is provided a semiconductor laser device comprising: a first semiconductor including an active layer having a pair of opposed resonance surfaces formed on a substrate; At least one end face that is outside the plane and faces the resonance plane and is inclined at an angle to the horizontal direction of the substrate.
And a second semiconductor having the same. In particular, the end face of the second semiconductor is a semiconductor laser device made of a facet. Thus, laser light emitted from the first semiconductor can be extracted to the outside with good beam characteristics.

In a semiconductor laser device according to a second aspect of the present invention, the second semiconductor has substantially the same composition. Thus, the laser light emitted from the first semiconductor can be efficiently extracted to the outside using the second semiconductor.

According to a third aspect of the present invention, in the semiconductor laser device, at least an end surface of the second semiconductor which is closer to a resonance surface of the first semiconductor is a facet, and further, a resonance surface of the first semiconductor is provided. A reflection film for reflecting the laser light resonated between the resonance surfaces on the end face of the second semiconductor closer to the second semiconductor. Thus, the laser light emitted from the first semiconductor can be more efficiently emitted to the outside.

According to a fourth aspect of the present invention, there is provided a semiconductor laser device, wherein a laser beam resonated between the resonance surfaces is transmitted on an end surface of the second semiconductor closer to the resonance surface of the first semiconductor. Having a membrane. Thus, the laser light emitted from the first semiconductor can be efficiently taken into the inside.

According to a fifth aspect of the present invention, in the semiconductor laser device, an end face of the second semiconductor farther from the resonance surface of the first semiconductor is a facet, and further, a side farther from the resonance surface of the first semiconductor. A reflection film that reflects the laser light that has entered the second semiconductor on the end face of the second semiconductor. Thereby, the laser light captured by the second semiconductor can be more efficiently reflected outside the second semiconductor, that is, below the substrate.

According to a sixth aspect of the present invention, there is provided a semiconductor laser device comprising: a first semiconductor including an active layer having a pair of opposed resonance surfaces formed on a substrate; and a first semiconductor outside the at least one resonance surface. A second semiconductor facing the resonance surface and having at least one end face at an angle inclined with respect to the horizontal direction of the substrate, wherein the second semiconductor is substantially the same. It is characterized by being composed of a composition. Thus, the laser light emitted from the first semiconductor can be efficiently extracted to the outside.

In the semiconductor laser device according to the present invention, the composition of the second semiconductor facing at least one of the resonance surfaces is different from the composition of the active layer of the first semiconductor. Thus, even when the second semiconductor is irradiated with the laser light from the first semiconductor, the laser is not excited, and can be a laser element with extremely little noise.

In the semiconductor laser device according to the present invention, the height of the second semiconductor provided on the substrate is equal to the height of the first semiconductor.
Higher than semiconductors. Thus, the direction of the laser light emitted from the first semiconductor can be changed efficiently. In particular, when the resonance surface is formed by etching, it is difficult for the resonance surface itself to be a mirror surface, so that the laser beam may spread. The present invention can efficiently emit laser light to the outside even in such a case.

According to the method of forming a semiconductor laser of the present invention, a first semiconductor including an active layer having a pair of opposed resonance surfaces formed on a substrate, and a first semiconductor outside the at least one resonance surface and facing the resonance surface. And a second semiconductor having at least one end face inclined at an angle with respect to the horizontal direction of the substrate. In the method of forming a semiconductor laser device, a semiconductor multilayer film having an active layer is formed on a substrate. Process and
Forming a first semiconductor having a pair of resonance surfaces facing each other by etching the semiconductor multilayer film; and forming at least one end surface on the substrate outside the at least one resonance surface, wherein at least one end surface is inclined with respect to the horizontal direction of the substrate. Selectively growing the second semiconductor at the specified angle. Thus, the laser light emitted from the first semiconductor can be extracted to the outside with good controllability. In particular, an extremely smooth surface can be formed with good mass productivity.

According to a tenth aspect of the present invention, in the method of forming a semiconductor laser, the first semiconductor and the second semiconductor are formed on a semiconductor selectively grown in a lateral direction. Thereby, each semiconductor can be formed with more controllability.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION As a result of various experiments, the present inventors have obtained a laser device using a specific mirror which is outside a resonance surface and has at least one end surface inclined at an angle with respect to the horizontal direction of the substrate. As a result, it has been found that the beam characteristics can be improved, the output of the laser can be dramatically increased, and high integration can be achieved, and the present invention has been made.

That is, when a mirror outside the resonance surface and having an end surface inclined at an angle with respect to the horizontal direction of the substrate is formed by etching, the shape of the beam emitted from the laser is deteriorated by passing through the mirror. There is a tendency. This is considered to be because the surface of the mirror formed by the etching is rough, and is particularly noticeable when a semiconductor having a plurality of layers is etched. Therefore, by forming a dielectric multilayer film or metal on the surface of a mirror formed by etching a semiconductor consisting of a plurality of layers, the surface roughness is slightly improved, but microscopically, it is mirror-finished. Not be. Therefore, it is difficult to correct the laser light emitted from the mirror surface by the optical system. In particular, when the resonance surface is formed by etching, the resonance surface itself does not become a mirror surface, and thus it is considered that the beam characteristics are deteriorated due to a synergistic effect of unevenness with the reflection surface.

According to the present invention, the direction of emission of a laser emitted from an active layer using a slope formed by etching a facet of a crystal or a semiconductor having substantially the same composition is adjusted to be above the substrate. Or below,
Can be changed.

FIG. 3 is a schematic sectional view showing the structure of a specific semiconductor laser. FIG. 3 shows an MO on a sapphire substrate.
An amorphous or microcrystalline buffer layer made of a nitride semiconductor formed by low-temperature growth using a CVD method, n-type GaN serving as a base layer, and S
In the opening of iO ₂ and SiO _2, the underlying n-type GaN surface is exposed. On the exposed surface, a single crystal of a nitride semiconductor is formed, and on the SiO ₂ surface, an n-type G is formed.
aN is not formed. Therefore, it is possible to form n-type GaN that becomes a contact layer for forming an n-type electrode with few crystal defects by lateral growth of the nitride semiconductor. Thus, the n-type I layer serving as a crack preventing layer is formed on the n-type GaN having few crystal defects.
nGaN, a superlattice multilayer film of AlGaN and GaN serving as an n-type cladding layer, n-type GaN serving as an optical guide layer, an active layer of a multiple quantum well structure in which two types of InGaN having different composition ratios are stacked, and a cap layer p-type AlGaN, p-type GaN to be an optical guide layer, AlG to be a p-type clad layer
A superlattice multilayer film of aN and GaN and p-type GaN to be a p-type contact layer are formed. p-type contact layer and p
The mold clad layer is formed into a ridge shape by etching.
Further, the first semiconductor is formed by exposing the n-type contact layer to form a resonance surface and an electrode formation surface. Note that a dielectric multilayer film of ZrO ₂ , SiO ₂ , and TiO ₂ is formed on the resonance surface.

Further, a second semiconductor having an inclined surface is formed at a portion facing the resonance surface. The second semiconductor is a semiconductor layer on a sapphire substrate, for example, FIGS.
As shown in (1), up to the n-type contact layer, a portion facing the resonance surface can be formed by etching to be exposed. Further, as shown in FIG. 3, the second semiconductor is partially exposed to the sapphire substrate, and on the exposed surface, via a striped n-type GaN parallel to the resonance surface,
It can also be formed.

Next, the nitride semiconductor is grown by selecting the flow ratio of the group III element and the group V element and the growth temperature, and the end face facing the resonance surface and having an angle inclined with respect to the horizontal direction of the substrate. Is formed. The inclined end face thus formed becomes a facet by selective growth.

On the other hand, after forming a second semiconductor having a rectangular or trapezoidal cross section and substantially the same composition, the end face may be inclined with respect to the horizontal direction of the substrate by etching. Hereinafter, the configuration of the present invention will be described in detail. (First Semiconductor) The first semiconductor of the present invention refers to a layer structure of a semiconductor formed over a substrate and capable of emitting a laser. Various configurations such as a Fabry-Perot electrode stripe structure, an internal stripe structure, a mesa stripe structure, and a ridge structure can be adopted as such a semiconductor structure. Although the first semiconductor can be formed of various semiconductors, a semiconductor using a nitride semiconductor using a sapphire substrate, a gallium nitride substrate, or a spinel substrate has a higher beam characteristic in growing the second semiconductor. It can greatly contribute to improvement and mass productivity.

In particular, sapphire (Al ₂ O ₃ ), spinel (MgAl ₂ O ₄ ), S
It is desirable to use a material having a thermal conductivity of 20 (k / Wm-1K-1) or more at normal temperature (300 K), such as iC, GaN, ZnO, etc., and particularly preferable is sapphire, spinel, GaN, ZnO. Choose a transparent material like A material having a high thermal conductivity can quickly radiate heat to a heat-radiating support such as a heat sink on which the laser element is mounted, so that the output of the laser element is increased. In the case where the first semiconductor is formed of a nitride semiconductor,
A double hetero structure having a pn junction can be obtained by using the MOCVD method or the HVPE method. After the first semiconductor layer structure is formed, a pair of resonance surfaces can be formed on the end surface of the active layer by etching.
Thereby, the resonance surface becomes a parallel mirror, and has an effect of causing light emission of the active layer to resonate between the resonance surfaces.

The etching method is roughly classified into wet etching and dry etching. In order to obtain a smooth surface having a resonance surface, it is preferable to use dry etching. The dry etching apparatus includes, for example, reactive ion etching (RIE), reactive ion beam etching (RIBE), electron cycloton etching (ECR), and ion beam etching (IBE).
Any of these devices may be used, and an etching device and an etching gas used for the etching device are appropriately used depending on the etching rate of the nitride semiconductor, the type of the protective film, and the like. For example, when using RIE,
By using a mixed gas of chlorine gas and silicon gas,
The nitride semiconductor can be etched with good controllability.

The structure of the multilayer film formed on the resonance surface is, for example, ZrO 2 so as to reflect the emission wavelength of the active layer.
₂ , TiO ₂ , SiO ₂ , Al ₂ O ₃ and other dielectric materials having different refractive indexes are designed to have a film thickness of λ / 4n (λ: wavelength, n: refractive index of nitride semiconductor). By laminating several to several tens of dielectrics designed in this way, a pair of opposed resonance surfaces can be created. Similarly, several to several tens of layers are laminated on the back surface of the substrate so that the thicknesses of the dielectrics having different refractive indices are also λ / 4n (λ: wavelength, n: refractive index of the dielectric). Thus, a resonance surface can be formed. (Second Semiconductor) The second semiconductor of the present invention is provided at a portion facing the resonance surface of the first semiconductor. Further, at least one of the end surfaces on the side closer to or farther from the first semiconductor forms an angle inclined with respect to the horizontal direction of the substrate. Thereby, the laser light can be emitted in a direction different from the horizontal direction of the substrate by the inclined end surface. For example, in the present invention, the second semiconductor is selectively grown, so that the end face is a facet. Here, the facet according to the present invention refers to a flat crystal plane appearing at the interface of the selectively grown crystal, and can be formed by selectively growing various semiconductors on a substrate. The surface roughness of the facet is preferably 10μ
m, preferably 5 μm or less, more preferably 1 μm or less.

In the present invention, the second semiconductor can be formed relatively easily by selective growth. In the case of a nitride semiconductor, a facet formed by selective growth has a flow rate ratio between a gas containing a group 3 element and a gas containing a group 5 element (a gas flow ratio of V / III of 2200 to 900).
Is preferred. ) And the forming temperature. That is, the formation temperature is about 980 ° C. to about 1050 ° C.
When the flow rate ratio of the gas containing the nitrogen element is increased, a facet having a triangular cross section and a relatively small inclination angle with respect to the substrate can be formed. On the other hand, when the formation temperature is about 1050 ° C. to about 1070 ° C., when the flow rate of TMG (trimethylgallium) or the like as a gas containing Ga is increased, a facet having a mesa-shaped cross section and a relatively sharp inclination angle to the substrate is formed. Can be.

Further, the second semiconductor having a facet at an end face can be constituted by a nucleation surface and a non-nucleation surface. When a nitride semiconductor is used, various nitride semiconductors can be used for the nucleation surface. On the other hand, sapphire, spinel, SiC, SiO ₂ and S
Various things such as iNx can be used. In particular, when a non-nucleation surface is used for the substrate surface, in order to form a second semiconductor, the first semiconductor is etched to the substrate surface while leaving a part of the first semiconductor, and the first semiconductor is formed in a direction parallel to the resonance surface. It is preferable to form a stripe. The second semiconductor can be formed by selectively growing the nitride semiconductor in a stripe shape. In this case, it is preferable to form by utilizing normal pressure CVD.

On the other hand, when exposing the first semiconductor without exposing the substrate and forming a non-nucleation surface thereon, a film to be a non-nucleation surface may be formed in the same wafer as shown in FIG. it can. In this case, the non-nucleation surface is partially removed by etching or the like to form a plurality of openings, so that the nucleation surface serving as a base is exposed. The underlying nucleation surface also greatly contributes to the shape of the second semiconductor. In this method, it can be formed relatively easily by the low pressure CVD method.

Further, the second semiconductor of the present invention having facets at the end faces can be made of substantially the same composition by selective growth. In this case, the structure can be different from the structure in which the active layer of the first semiconductor is formed. Therefore, even if the second semiconductor is irradiated with the laser light, the second semiconductor is not optically excited and does not cause noise or the like. Similarly, since the second semiconductor is made of the same composition by selective growth, it is possible to minimize the loss of light utilization due to stress, crystal defects, and the like. In particular, when the second semiconductor is formed of GaN, GaN
Is effective because the band gap is large among the III-V compound semiconductors and the second semiconductor can minimize the absorption of laser light emitted from the first semiconductor.

Further, the second semiconductor of the present invention can be formed as follows. That is, after the first semiconductor is formed, the material forming the second semiconductor is used, and the portion where the second semiconductor is to be formed has a relatively sharp inclination angle with respect to the substrate, that is, the cross section is substantially rectangular. Or a trapezoidal semiconductor is selectively grown. Next, by etching this semiconductor, a second semiconductor having an end surface having a desired inclination angle with respect to the substrate can be formed. In particular, a second semiconductor having an end surface having an inclination angle of about 45 degrees with respect to the substrate can be formed by isotropic etching. Here, the second semiconductor has substantially the same composition. The same composition in the present specification includes, for example, a case where the compounding ratio continuously changes. By forming the second semiconductor as described above, from the first semiconductor,
Laser light emitted parallel to the substrate can be changed more perpendicularly to the substrate. In addition, as isotropic etching, there are roughly divided into wet etching and dry etching, but in order to obtain a smooth surface,
It is desirable to use dry etching. Examples of the etching apparatus include those described above.

Further, the second semiconductor of the present invention has an end face parallel to the resonance surface of the first semiconductor, that is, perpendicular to the horizontal direction of the substrate, on the end face on the side closer to the first semiconductor. be able to. Accordingly, when a transmission film described later is provided on the surface of the second semiconductor closer to the resonance surface of the first semiconductor, the laser light emitted from the first semiconductor can be efficiently introduced into the second semiconductor. Can be captured.

Also, the second semiconductor can be larger than the first semiconductor. Thus, the direction of the laser light emitted from the first semiconductor can be changed efficiently. Specifically, the height (total film thickness) of the first semiconductor
Is about 7 μm, while the height of the second semiconductor is about 30 μm.
m can be arbitrarily formed. (Reflection Film) The reflection film of the present invention is formed on the surface of the second semiconductor, reflects the laser light resonated between the resonance surfaces of the first semiconductor, and moves the laser light in the horizontal direction of the substrate. Used to emit in different directions. That is, by providing this reflection film on at least one of the end faces on the side closer to and farther from the resonance surface of the first semiconductor on the second semiconductor, the laser light can be efficiently extracted and the waveguide-type laser element for edge emission is provided. Can be made into a surface emitting laser element.
Such a reflection film can be formed by, for example, a dielectric multilayer film, a metal thin film, or the like. The dielectric multilayer film is laminated by adjusting each film thickness to λ / 4n. In the case of a metal thin film, a metal material having a reflectance with low absorption at the emission wavelength of the active layer is formed by using a film forming apparatus such as evaporation and sputtering. (Transmissive Film) The transparent film of the present invention is preferably formed on at least a part of the surface of the second semiconductor closer to the resonance surface of the first semiconductor when the laser light is taken into the second semiconductor. Is what is done. That is, by providing this transmission film on the end face of the second semiconductor closer to the resonance face of the first semiconductor, laser light can be efficiently taken in.
Such a transmission film can be formed by, for example, a dielectric multilayer film. The dielectric multilayer film has a thickness of λ / 2.
It is adjusted to n and laminated.

Hereinafter, specific embodiments of the present invention will be described in detail, but it is needless to say that the present invention is not limited thereto.

[0036]

(Embodiment 1) A schematic cross section of FIG. 1 and FIG. 2 shows a schematic structure of a ridge stripe type laser device of the present invention. The laser element is formed using a nitride semiconductor. TMG as source gas by metal organic chemical vapor deposition
(Trimethylgallium) gas, TMI (trimethylindium) gas, TMA (trimethylaluminum) gas, nitrogen gas, silane gas, cyclopentadienyl magnesium gas as impurity gas, and nitrogen gas and hydrogen gas as carrier gas are appropriately fed to the reaction furnace. Thereby, a nitride semiconductor can be formed. The structure of the laser element is such that a G
A buffer layer (204) of aN is grown. Next, n-type GaN (105, 205) serving as a base layer is formed.
It is formed on GaN using SiO ₂ as a mask. The underlying n-type GaN is partially etched down to the sapphire substrate using a mask to form striped GaN (104). After removing the mask, the GaN surface becomes a nucleation surface on which a single crystal of the nitride semiconductor is formed, and the n-type GaN to be formed thereon is not formed on the sapphire exposed surface. Therefore, the n-type G that becomes a contact layer for forming an n-type electrode with few crystal defects due to lateral growth of the nitride semiconductor
aN can be formed. Thus, n-type G with few crystal defects
n-type InGaN (10
6, 206), AlGaN and Ga to be n-type cladding layers
N-type superlattice multilayer film (107, 207), n-type GaN (108, 208) serving as an optical guide layer, and active layer (109, 209) having a multiple quantum well structure in which two types of InGaN having different composition ratios are stacked. , P-type AlGa as cap layer
N (110, 210), p-type GaN to be an optical guide layer
(111, 211), AlGaN to be a p-type cladding layer
And a GaN superlattice multilayer film (112, 212) and a p-type GaN (113, 213) to be a p-type contact layer. The p-type contact layer and the p-type clad layer are formed into a ridge shape by etching. Further, the first semiconductor is formed by exposing the n-type contact layer to form a resonance surface and an electrode formation surface. Note that the nitride semiconductor layer is etched by using a mixed gas of chlorine gas and silicon gas using a reactive ion etching (RIE) device.

Next, in the present invention, the resonance surface (216) is opposed to the resonance surface (216).
A second semiconductor having an inclined surface is formed
You. The second semiconductor contacts the portion facing the resonance surface.
Partially etched to n-type GaN,
And is formed on the exposed surface. Exposed n-type GaN
Afterwards, SiO_TwoIs formed by a sputtering method.
You. This SiO_TwoIn the direction parallel to the resonance surface of the first semiconductor
And a vertical stripe with a width of about 6 μm perpendicular to the A-axis direction of sapphire.
A tripe-like groove is formed. The bottom of the groove is a nucleation surface
The n-type GaN (205) surface is exposed. On the other hand, S
iO_Two(202) The surface acts as a non-nucleated surface. Nucleation
The semiconductor wafer covered with the non-nucleation surface except the surface is
105 is placed in a reactor for forming a semiconductor and 105
Heated to 0 ° C and the flow ratio of the source gas different from that of the first semiconductor
Flow. Specifically, the flow ratio of nitrogen gas / TMG gas is set to 2
Selectively grow single crystal by flowing with carrier gas as 200
Let it. The selectively grown second semiconductor (201) resonates
From the end surface facing the surface, ie, the resonance surface of the first semiconductor
Near end face and end far from resonance face of first semiconductor
The facet is inclined with respect to the substrate and the facet is (1-101).
(200) (note that -1 has a bar on top)
Means 1. ). The cross section of the second semiconductor is an approximately equilateral triangle
And the height is about 9 μm. Exposed mask
SiO_TwoIs removed, the first semiconductor active layer and the second semiconductor layer are removed.
By forming a dielectric multilayer film on the end face of the conductor,
Form the resonance surface (216) and the reflection film (215) to be a row mirror
Let it run. Even if the resonance surface is provided only on the side that becomes the reflection surface,
Good. The dielectric multilayer film is made of ZrO_Two, TiO_Two, SiO_Two,
Al_TwoO_ThreeThe thickness of each dielectric with different refractive index is the same.
Λ / 4n (n: refractive index of dielectric)
The layers are laminated in several layers. Finally, charge each contact layer
By forming the poles (102, 114, 214).
Thus, the selectively grown second semiconductor is shared with the first semiconductor layer.
The laser light emitted from the vibration surface is different from the direction parallel to the substrate.
As a mirror that changes the direction
The semiconductor laser device can be used. Embodiment 2 As shown in FIG.
The semiconductor laser element is connected to the resonance surface (616) of the first semiconductor.
Permeable membranes (615) on the end faces on the near side and the far side
And the reflection film (617), as in Example 1.
It is formed. Note that the resonance surface composed of a dielectric multilayer film
And the reflection film is made of ZrO._Two, TiO_Two, SiO _Two, Al_TwoO_Three
The thicknesses of the dielectric materials having different refractive indices such as λ /
Several layers to several tens so that 4n (n: refractive index of dielectric)
Laminated into layers. The permeable membrane is made of ZrO_Two, TiO_Two,
SiO_Two, Al_TwoO_ThreeOf dielectric materials with different refractive indexes
Each film thickness is set to λ / 2n (n: refractive index of dielectric)
And several to several tens of layers. To be configured in this way
The second semiconductor selectively grown is replaced with the first semiconductor
The laser light emitted from the resonance surface of the layer in the direction parallel to the substrate
Is a mirror that changes in a different direction, ie below the substrate
Can be used as a semiconductor laser device
You. (Third Embodiment) As shown in FIG.
The semiconductor laser element is formed by a second semiconductor having a substantially rectangular cross section.
After the formation, the second side near and far from the first semiconductor is formed.
Edge of semiconductor is isotropically etched to substrate
Except for having a tilt angle of about 45 degrees, the shape is the same as in Example 1.
Is done. First, the part facing the resonance surface (716) is
Partially etched down to n-type GaN (705)
And expose it. After exposing n-type GaN,
SiO by sputtering method_TwoFirst mask made of
To form Next, this SiO_TwoIn the second semiconductor
Form stripe-shaped grooves corresponding to the parts where the body should be formed
I do. The bottom of the groove is n-type GaN (705) to be a nucleation surface
The surface is exposed. Non-nucleated surface covered except nucleated surface
Reactor for forming a first semiconductor from the semiconductor wafer
And growing a single crystal of GsN
You. Here, the grown second semiconductor has a substantially rectangular cross section.
And the height is about 9 μm. Next, this section is almost
In the center of the second rectangular semiconductor, further SiO 2_TwoConsists of
A second mask is formed, and chlorine gas and silicon
Isotropic etching is performed using elemental gas. This allows
A second half having an end surface at an inclination angle of about 45 degrees with respect to the substrate;
A conductor (701) is formed. SiO_TwoThe first consisting of
After removing the second mask and the second mask, the active layer of the first semiconductor and the second
The end face of the second semiconductor, which is closer to the first semiconductor, is
By forming a layer film, the resonance surface (7
16) and a reflection film (715) are formed. Note that resonance
The surface may be provided only on the side that becomes the reflection surface. Where the dielectric
The resonance surface and the reflection film composed of the multilayer film are made of ZrO._Two,
TiO_Two, SiO_Two, Al_TwoO_ThreeEtc. with different refractive indices
Each film thickness of the dielectric is similarly set to λ / 4n (n: refraction of the dielectric)
Is laminated in several layers to several tens of layers so that the ratio becomes as follows. This
With this configuration, a slope with an inclination angle of about 45 degrees is provided.
Released from the resonance surface of the first semiconductor layer.
To change the laser beam in a direction almost perpendicular to the substrate.
Semiconductor laser device that can be used as a mirror
Can be.

[0038]

According to the laser device of the present invention, the laser beam can be changed to a direction different from the parallel direction of the substrate with good controllability by using the second semiconductor that has been selectively grown. In particular, a desired laser beam can be obtained without impairing the beam characteristics.

Further, since a plurality of light emitting portions can be formed in the same wafer, individual characteristics of the laser element can be measured in the state of the wafer without being separated one by one.
Can be inspected. Similarly, it can be used as a monolithic display.

Further, if laser light is extracted from the same surface side, it can be used as a light source for illumination. For example, the efficiency of an LED is around 15%, the efficiency of a fluorescent lamp is around 25%, and the efficiency of an incandescent lamp is only around 7%. However, when the laser element of the present invention is used as such a light source for illumination, a light source with very high luminous efficiency of 70% or more and low power can be provided. In addition, since the nitride semiconductor has a band gap of 1.9 eV to 6.1 eV, blue, green, and red light emission can be obtained in the same device. Therefore, similarly to the display, it is possible to reproduce various color tones with one illumination. In addition, when a portion that reflects laser light is provided as in the present invention, the laser light is easily spread. However, if the light source is an illumination light source, it is not necessary to condense the light, and it is preferable that the light is diffused. An element is suitable. When used as a light source for illumination, a more preferable light source can be provided by disposing a member such as a phosphor or a light diffusing agent that diffuses the laser light on the side of the laser light emission observation surface.

In the case where high integration of laser light is intended,
Although the overall calorific value is extremely large, a nitride semiconductor has an advantage that it can withstand heat generation because a transparent and high thermal conductivity material such as sapphire or spinel is used for the substrate. Further, the fact that the substrate is transparent provides a very preferable light source because unlike conventional light-emitting devices using opaque substrates such as GaP and GaAs, laser light can be extracted from the substrate side with little loss. can do.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a laser device according to a first embodiment of the present invention when viewed from a direction parallel to a resonance surface.

FIG. 2 is a schematic cross-sectional view of the laser device according to the first embodiment of the present invention as viewed from a direction parallel to a ridge stripe.

FIG. 3 is a schematic sectional view showing a schematic structure of another laser device of the present invention.

FIG. 4 is a schematic plan view illustrating a nucleation surface for forming a second semiconductor.

FIG. 5 is a schematic sectional view showing a schematic structure of a laser device shown for comparison with the present invention.

FIG. 6 is a schematic cross-sectional view of a laser device according to a second embodiment of the present invention as viewed in a direction parallel to a ridge stripe.

FIG. 7 is a schematic cross-sectional view of a laser device according to a third embodiment of the present invention, as viewed from a direction parallel to a ridge stripe.

[Explanation of symbols]

101: ZrO _X 102: n-electrode 103, 203, 603, 703: sapphire to be a substrate 104: GaN striped buffer layer 105, 205, 605, 705: n-GaN 106, 206, 606, 706: crack preventing layer N-In _0.1 Ga _0.9 N 107, 207, 607, 707... N serving as a cladding layer
-Al _0.14 Ga _0.86 N / GaN MD-SLS 108, 208, 608, 708 ... n- to be a guide layer
GaN 109, 209, 609, 909... In _0.02 Ga _0.98 N / In _0.15 Ga _0.85 N 110, 210, 610, 710...
-Al _0.2 Ga _0.8 N 111, 211, 611, 711...
GaN 112, 212, 612, 712... P serving as a cladding layer
-Al _0.14 Ga _0.86 N / GaN MD-SLS 113,213,613,713 ... p-GaN 114,214,614,714 ... p electrode to be a contact layer 200,300,400,600 ... End face of the second semiconductor Facets 201, 301, 601, 701. GaN 202, 602 constituting the second semiconductor. SiO ₂ 204, 604, 704, which is a non-nucleus molding surface. Buffer layers 215, 617, 715, of GaN. dielectric multilayer film 216,521,522,616,716 ... resonant surface 302,303 ... SiO ₂ 401 ... SiO ₂ openings 402 formed by etching using the remaining buffer layer 304 ... lateral selective growth by etching .., First semiconductor 403, stripe 510, substrate 511, n-type nitride semiconductor 512, The end surface of the second semiconductor formed by a dielectric multilayer film 700 ... etching the sexual layer 513 ... p-type nitride semiconductor 523 ... mirror 615 ... permeable membrane

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5D119 AA43 CA10 FA05 5F073 AA13 AA74 AA77 AA83 AB29 BA01 BA09 CA07 CB05 DA05 DA25 DA31 DA33 EA24

Claims (10)

[Claims] A first semiconductor including an active layer having a pair of opposed resonance surfaces formed on a substrate; and a first semiconductor outside the at least one resonance surface, facing the resonance surface, and in the horizontal direction of the substrate. A second semiconductor having at least one end face inclined at an angle with respect to the substrate, wherein the end face at an angle inclined with respect to the horizontal direction of the substrate is a facet. Laser element. 2. The semiconductor laser device according to claim 1, wherein said second semiconductor has substantially the same composition. 3. An end face of the second semiconductor at least on a side closer to a resonance surface of the first semiconductor is a facet, and an end face of the second semiconductor on a side closer to a resonance surface of the first semiconductor. 3. The semiconductor laser device according to claim 1, further comprising a reflection film for reflecting laser light resonated between the resonance surfaces. 4. A transmission film for transmitting a laser beam resonated between resonance surfaces on an end surface of the second semiconductor which is closer to a resonance surface of the first semiconductor. 3. The semiconductor laser device according to 1 or 2. 5. The end face of the second semiconductor farther from the resonance face of the first semiconductor is a facet, and further on the end face of the second semiconductor farther from the resonance face of the first semiconductor. And a reflection film for reflecting the laser light that has entered the second semiconductor.
And the semiconductor laser device according to 4. 6. A first semiconductor including an active layer having a pair of opposing resonance surfaces formed on a substrate, and a first semiconductor outside at least one of the resonance surfaces, opposing the resonance surface, and in the horizontal direction of the substrate. A second semiconductor having at least one end face inclined at an angle with respect to the second semiconductor, wherein the second semiconductor has substantially the same composition. Laser element. 7. The semiconductor laser according to claim 1, wherein a composition of a second semiconductor facing the at least one resonance surface is different from a composition of an active layer of the first semiconductor. element. 8. The semiconductor laser device according to claim 1, wherein the height of the second semiconductor provided on the substrate is higher than the height of the first semiconductor. 9. A first semiconductor including an active layer having a pair of opposed resonance surfaces formed on a substrate, and a first semiconductor outside the at least one resonance surface, facing the resonance surface, and in the horizontal direction of the substrate. A second semiconductor having at least one end face inclined at an angle to the semiconductor laser device, comprising: a step of forming a semiconductor multilayer film having an active layer on a substrate; Forming a first semiconductor having a pair of opposed resonance surfaces by etching; and forming at least one end surface on the substrate outside the at least one resonance surface at an angle inclined with respect to the horizontal direction of the substrate. Selectively growing a second semiconductor. A method for forming a semiconductor laser device, comprising: 10. The method according to claim 9, wherein the first semiconductor and the second semiconductor are formed on a semiconductor selectively grown in a lateral direction.