JP2001148544A - Semiconductor light-emitting element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a light leaking from a propagation layer to a clad layer from generating a light which propagates in multiple mode between a substrate and a light-confining clad layer by making a Si-doped GaN film thick, to improve the characteristics of a crystal constituting a laser. SOLUTION: A growth suppression film 104 is formed on an n-GaN layer 103, an InGaN re-grown layer 105 is formed from a part, where the growth suppressing film 104 is not formed, thereby lessening the dislocation propagating from the substrate interface and improving the characteristics of a light-emitting element formed thereon.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nitride semiconductor film having excellent temperature characteristics at a high temperature, and a light emitting element used as a light source for a display element, a display, and an optical disk composed of the nitride semiconductor.

[0002]

2. Description of the Related Art Nitride compound semiconductors have been used and studied as light emitting devices and high power devices. For example, in the case of a light-emitting element, by adjusting its composition, it can be used as a light-emitting element in a wide wavelength range from blue to orange in theory. In recent years, a blue light emitting diode or a green light emitting diode has been put to practical use by utilizing its characteristics, and a blue-violet semiconductor laser device has been developed.

[0003] Sapphire, SiC, spinel, Si, GaAs are used as substrates for manufacturing a nitride semiconductor film.
Etc. are used. For example, when a sapphire substrate is used, GaN or AlN is preliminarily formed at a low temperature of about 500 ° C. to 600 ° C. before epitaxially growing a GaN film.
Buffer layer is formed, and then the substrate temperature is set to 1000 ° C.
When the temperature is raised to about 1100 ° C. and the nitride semiconductor film is epitaxially grown, a crystal having a good surface condition and good structural and electrical properties can be obtained. In the case of a SiC substrate,
High quality crystals can be obtained by using a thin AlN buffer layer at a growth temperature at which epitaxial growth is performed.

However, no matter which substrate is used, the difference in thermal expansion coefficient and lattice constant from the nitride semiconductor film causes
10 ⁹ cm ^-2 to 10 ⁷ c in the manufactured nitrogen compound semiconductor
There are high-density defects up to m ^-2 . This defect is classified into edge transition and spiral transition.

It is known that these defects act as carrier traps and thus impair the electrical characteristics of the manufactured crystal. In particular, the lifetime characteristics of a device such as a laser which injects a large current are deteriorated. Attempts have been made to reduce defects.

For example, Appl. Phys. Lett.
71 (18) p2638-2640 and Appl. Ph
ys. Lett. In 71 (16) p2259-2261, a mask of SiO ₂ is formed in the GaN layer, by selective growth, has been published that the defect density of the mask upper portion is reduced two orders of magnitude. Similarly, in the method of performing selective growth using a mask, there is a report in the 45th Applied Physics-related lecture conference proceedings 28a-ZS-6 that the selective growth is performed using a tungsten mask and that the method is applied to an electronic device. . Regarding lasers, reports of lasers manufactured by applying the above-described selective growth technology of SiO ₂ to reduce the transition density in the crystal are reported in, for example, Journal of Applied Electronic Properties, Vol.
No. 1989, p. 53-58. In this report, a stripe-shaped SiO ₂ selective growth mask is formed on an n-type GaN film, and an n-type GaN film is grown on the mask to cover the SiO ₂ film to form a flat surface. SiO ₂
The document describes that by forming a laser structure on a coating portion, defects in a laser element are reduced and element characteristics are improved.

[0007]

According to the method described above, G
When a SiO ₂ mask is formed on the aN film and the selective growth is performed, GaN itself is unstable at a high temperature. Therefore, depending on the growth conditions, voids may be generated at the coupling portion of the selective growth film on the SiO ₂ mask ( For example, Appl. Phys.
t. 71 (18) 1997, p. 2638-2640), there was a case where an edge defect was concentrated at one location (for example, Appl. Phys. Lett. 71 (1)
6) 1997p2259-2261). Also, in order to obtain a uniform and flat GaN film, it was necessary to grow the film under reduced pressure.

In addition to the above problems, there is an inherent problem that occurs when a nitride semiconductor laser device is manufactured on a heterogeneous substrate. In other words, in order to improve the characteristics of the crystal constituting the laser, the underlying Si-doped GaN film must be thickened. Multi-mode propagating light is generated between the cladding layers.

[0009]

The semiconductor light emitting device of the present invention comprises a substrate, a nitride compound semiconductor layer, a growth suppressing film formed on a part of the surface of the nitride compound semiconductor layer, a regrowth layer and an active layer. In the semiconductor light emitting device having the above, the regrowth layer is formed on the nitride compound semiconductor layer and the growth suppressing film, and contains In.

[0010] In the semiconductor light emitting device of the present invention, the growth suppressing film has a stripped portion, and the effective refractive index at a position corresponding to the striped portion is higher than that around the striped portion. As a result, laser oscillation is caused at a position corresponding to the stripped portion.

[0011] The semiconductor light emitting device of the present invention is characterized in that the growth suppressing film has a stripped portion and includes at least a part of an insulating film.

The semiconductor light emitting device of the present invention is characterized in that the growth suppressing film is formed vertically below the laser stripe and is made of a material that absorbs or reflects light generated in the active layer. .

The semiconductor light emitting device of the present invention is characterized in that the growth suppressing film is formed between the substrate and the active layer.

In the semiconductor light emitting device of the present invention, the active layer is formed above the regrown layer, the regrown layer has a concave portion at a position corresponding to the lack of the growth suppressing film, and the active layer is formed of the regrown layer. Characterized by being formed along the uneven shape.

In the semiconductor light emitting device of the present invention, the active layer is formed above the regrown layer, the regrown layer has a concave portion at a position corresponding to the growth suppressing film, and the active layer has a concavo-convex shape of the regrown layer. It is characterized by being formed along.

According to the method of manufacturing a nitride semiconductor multilayer structure of the present invention, there is provided a method of manufacturing a nitride semiconductor multilayer structure, comprising the steps of: forming a first nitride semiconductor; and growing a part of the surface of the first nitride semiconductor. The method is characterized by including a step of forming a suppression film and a step of starting formation of a nitride semiconductor containing In from a surface of the nitride compound semiconductor where the growth suppression film is not formed.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the present invention will be described in detail.

Generally, sapphire, SiC, GaN, GaAs
s, MgAl ₂ O ₄ or the like is used. Further, as a crystal growth method, it is usual to use a metal organic chemical vapor deposition method (hereinafter, MOCVD method), a molecular beam epitaxy method (hereinafter, MBE method), and a hydride vapor phase epitaxy method (hereinafter, H-VPE method).
However, in consideration of the crystallinity and mass productivity of a nitride semiconductor to be manufactured, it is most common to use sapphire or GaN as a substrate and grow crystals by MOCVD. An example of a nitride semiconductor laser manufactured by a MOCVD method using a sapphire substrate will be described below.

FIG. 2 shows the MOCVD used in the embodiment.
1 shows a schematic view of the device. In the figure, reference numeral 201 denotes a sapphire or GaN substrate having a (0001) plane, which is disposed on a susceptor (202) made of carbon. A heater for resistance heating, also made of carbon, is disposed inside the susceptor, and the temperature of the substrate can be monitored and controlled by a thermocouple. Reference numeral 203 denotes a reaction tube made of double quartz, which is water-cooled. Ammonia (206) is used as a group V raw material, and trimethylgallium (hereinafter, TMG), trimethylaluminum (hereinafter, TMA), and trimethylindium (hereinafter, TMI) are used as a group III raw material.
(207a to 207c) were used by bubbling with nitrogen gas or hydrogen gas. Further, SiH ₄ (monosilane) (209) was used as an n-type doping material, and biscyclopentadienyl magnesium (Cp ₂ Mg) (207d) was used as a p-type doping material.
Each raw material is a mass flow controller (MFC) (208)
The flow rate is accurately controlled by the above method, and the raw material is introduced into the reaction tube through the raw material inlet (204) and discharged through the exhaust gas outlet (205).

Hereinafter, the procedure of crystal growth of each layer constituting the semiconductor laser will be described with reference to FIGS. 1, 3 and 4.
First, a procedure for growing a crystal up to a cladding layer of a laser will be described with reference to FIG.

First, the substrate (301) is washed and set in a crystal growth apparatus. The substrate is heat-treated in a hydrogen atmosphere at a temperature of about 1100 ° C. for about 10 minutes, and thereafter, at a temperature of 500 ° C. to
Cool down to about 00 ° C. When the temperature becomes constant, the carrier gas is replaced with nitrogen, the total flow rate is 10 l / min, the ammonia is 3 l / min, and after a few seconds, TMG is reduced to about 20 μmo.
1 / min and a buffer layer (30
2) was grown to about 20 nm in about one minute. When a GaN substrate is used, the buffer layer (302) may be omitted. Thereafter, the supply of TMG is stopped and 105
The temperature was raised to 0 ° C., and TMG was added again at about 50 μmol / min.
And an SiH ₄ gas were supplied at about 10 nmol / min to grow an n-type GaN film (303) of about 4 μm. Thereafter, the grown film is once taken out, and the SiO ₂ growth suppressing film (304) is formed to a thickness of about 0.1 μm by using a sputtering method or an evaporation method.
m, and the underlying n-type GaN film is exposed by using simple photolithography to etch the SiO ₂ film in a stripe shape with a width of 5 μm and an interval of 10 μm (3)
05). After that, the apparatus was set again in the crystal manufacturing apparatus and replaced with nitrogen gas.
The temperature was raised to 700 ° C. while flowing at a rate of 1 / min, and when the temperature was stabilized, about 50 μmol / min of TMG and SiH ₄
About 10 nmol / min of gas and 10 μm of TMI
ol / min to supply n-type In _0.1 Ga _0.9 N (306)
Grow. As the growth progressed, In _0.1 Ga _0.9 N started regrowing from the exposed n-type GaN (305),
It grows laterally on the portion covered by iO ₂ .
When the regrown In _0.1 Ga _0.9 N has a thickness of about 0.2 μm, the portion grown in the lateral direction is completely bonded to the covering portion, and the film surface becomes flat (307). After the regrowth of InGaN, the supply of TMG, TMI and SiH ₄ was stopped, and
The temperature was raised to 50 ° C., nitrogen was 10 l / min, ammonia was 3 l / min, TMG was about 50 μmol / min, S
About 10 nmol / min iH ₄ gas and 1 TMA
N-type A that becomes 0 μmol / min and becomes a light confinement layer
Grow _0.15 Ga _0.85 N (308).

The surface of the film manufactured through the above steps is flat and free from cracks. In observation by a transmission electron microscope, in In _0.1 Ga _0.9 N and Al _0.15 Ga _0.85 N covering the SiO ₂ film, almost no defects generated from the interface between the substrate and the GaN film could be observed. The helical transition and the edge transition were bent on the SiO ₂ growth suppressing film at the portion not covered by the SiO ₂ film (the upper part of 305 in FIG. 3), and disappeared while canceling each other. FIG. 4 schematically shows the state of the transition. In the figure, 401 is a substrate, 402 is a low-temperature buffer layer, 403 is a GaN film, and 404 is SiO _2.
Growth suppression film, 405 is an In _0.1 Ga _0.9 N film, 406 is A
The l _0.15 Ga _0.85 N film, 407, is a transition generated from the substrate interface. As shown in the figure, most of the dislocations are concentrated on the growth suppressing film and disappear, and have not reached the surface of the film. Further, when compared with a GaN film selectively grown in the same manner, G
threading edge dislocations that are many observed in the joint portion of the regrowth layer to each other in the case of aN of selective growth, was hardly observed in the joint portion of the In _0.1 Ga _0.9 N regrown layer. This is because the inclusion of In in the film to be regrown lowers the rigidity of the crystal and facilitates the growth in the lateral direction.
It is considered that this is because the dislocation of the dislocation is prevented by distorting the lattice of _0.1 Ga _0.9 N, and at the same time, the regrown films are easily coupled in the lateral direction. The In composition of In _x Ga ₁ -xN regrown on the growth suppressing film may be as high as, for example, In _0.8 Ga _0.2 N, so that the crystallinity of the regrown layer is not deteriorated. Considering the crystallinity of each layer above and the ease of coating the growth suppressing film, x = 0.05 to 0.
A range of 25 is most preferred. Generally I less than 0.05
In the case of the n composition, the rigidity of the regrown layer is high, so that distortion is hardly caused and the transition is easily propagated. Further, it is difficult to bond the regrown layer in the lateral direction. On the other hand, if the In composition is higher than 0.25, In in the regrown layer is likely to aggregate, and a region having a non-uniform composition is likely to be generated. When such a region is generated, the non-uniform composition becomes a source of a new dislocation during the subsequent growth, and may adversely deteriorate the crystallinity of each layer above the regrown layer. Further, the thickness of the InGaN regrown layer completely covering the growth suppression film basically depends on the thickness and shape of the growth suppression film, and there is no problem if the thickness completely covers the growth suppression film. In general, it is preferable to regrow InGaN to a thickness of about 10 times the thickness of the growth suppressing film in consideration of the flatness of the regrowth layer and the crystallinity of each layer above the regrowth layer.

Next, a description will be given with reference to FIG. 101 is a sapphire substrate, 102 is a buffer layer, 103 is an n-type G
aN layer; 104, a growth suppressing film; 105, an InGaN regrown layer; 106, an n-type AlGaN cladding layer;
Type light propagation layer, 108 is a multiple quantum well active layer, 109 is p
Type propagation layer, 110 is a p-type AlGaN cladding layer, 111
Denotes a p-type contact layer, 112 denotes an n-type electrode, 113 denotes an insulating film, and 114 denotes a p-type electrode. In the figure, reference numeral 107 denotes a GaN light propagation layer having a thickness of about 0.1 μm, which is the n-type Al _0.15 Ga _0.85 N cladding layer 106 (30 in FIG. 3).
Subsequently, the supply of TMA was stopped, and the growth was continued. Buffer layer 1 shown in FIG.
From 02 to n-type Al _0.15 Ga _0.85 N cladding layer 106, the crystal growth of the nitride compound semiconductor can be performed in exactly the same manner as the procedure described with reference to FIG.

After growing the GaN light propagation layer 107, the TMG
And SiH_FourIs stopped and the temperature of the substrate is set to 700 ° C to 8 ° C.
Reduce to about 00 ° C, supply TMI and TMG,
nm of In_0.15Ga_0.85N and 4 nm thick In_0.02Ga
_0.98N multiple quantum well active layer (1
08) grow. At that time, SiH_FourMay be supplied
It is not necessary to supply. Then, TMG and TMI
After the supply was stopped again and the temperature was raised again to 1050 ° C., the TM
G and TMA are supplied, and a 20-nm thick Al _0.15Ga
_0.85A carrier block layer made of N is grown. That
When Cp_TwoMg may or may not be supplied
In addition, even without this layer, no major trouble occurs. That
Thereafter, the supply of TMA was stopped, and TMG was supplied at 50 μmol / m
in, Cp _TwoSupplying about 50 nmol / min of Mg
Grow a 0.1 μm thick p-type GaN light propagation layer (109)
You. Further, TMA is supplied at a rate of 10 μmol / min,
0.5 μm p-type Al_0.15Ga_0.85Cladding made of N
The layer (110) is grown, and finally the supply of TMA is stopped.
Layer of 0.1 μm thick p-type GaN
After growing (111), the substrate temperature is lowered to room temperature and
The crystal growth film is taken out from the growth apparatus. Then, dry dry
The n-type GaN film is exposed using a
forming an n-type electrode (112) by depositing a u film on the exposed portion
You. In addition, an insulating film (SiO_Two) (113)
P-type GaN
The contact layer (111) is exposed, and the Ni and Au films are evaporated.
To form a p-type electrode (114). Finally, cleavage
Or, use dry etching to form the mirror end face.
To achieve. As described above, the blue-violet
A laser having an emission wavelength can be manufactured.

In the laser fabricated by this method, the dislocation density in each film after regrowth is reduced by two digits or more due to the presence of the growth suppressing film provided between the n-type GaN layer and the AlGaN cladding layer. . In addition, as compared with a laser manufactured by forming a growth suppression film in a GaN film according to a conventional technique, not only the transition density of a portion coated on the growth suppression film and the dislocation density of an uncoated portion are reduced, The edge-like transition that has been concentrated on the regrowth film bonding portion on the growth suppressing film has disappeared. Therefore, the transition density of the grown film after the guide layer constituting the laser decreases without depending on the location,
As a result, the life characteristics of the laser itself were improved 10 times or more.

In this embodiment, the case where a GaN film is used as the low-temperature buffer layer has been described. However, Al _x Ga ₁ -xN
There is no problem even if (0 ≦ x ≦ 1) is used. Further, in this example, the case where the In composition of the nitrogen compound semiconductor film to be regrown is 0.1 is described, but the In composition is 0 <x.
A similar effect was observed in the case of a nitrogen compound semiconductor having (In) ≦ 1, and a particularly remarkable effect was observed in a nitrogen compound semiconductor having an In composition of 0.05 ≦ x (In) ≦ 0.25.

It is not necessary to fix the shape of the growth suppressing film, but the stripe direction is <1-10 of the nitride compound semiconductor.
In the case of 0> direction, lateral growth is further promoted, which is preferable.

In forming the stripe structure, the interval is preferably 50 μm or less, and the width of the growth suppressing film is preferably 20 μm or less, but not limited thereto, and more preferably the interval is 20 μm.
Hereinafter, when the width of the growth suppressing film was 10 μm or less, a good result was obtained with a flat surface and a low defect density. this is,
By the ratio of the growth rate in the thickness direction to the growth rate in the lateral direction, I
This is because the thickness by which the nGaN regrown layer completely covers the growth suppression film is determined. When the interval is 20 μm or less and the width of the growth suppression film is 10 μm or less, the growth suppression film is covered with a thickness that does not impair the crystallinity. Can be exhausted. Embodiment 1 In this embodiment, an example in which a laser is manufactured using an insulator as a growth suppressing film will be described.

After the growth of the n-type GaN layer, the substrate is taken out of the growth apparatus, and a 2.5 μm-wide SiN film is formed on the underlying GaN at intervals of 5 μm in the <1-100> direction in the form of stripes. After returning the substrate to the growth apparatus and re-growing InGaN having a thickness of about 0.2 μm,
Another layer including an n-type AlGaN cladding layer having a thickness of μm was grown, and a structure shown in FIG. 1 was formed through an element fabrication process.
In this structure, on the part where the growth suppression film is not covered,
Electrodes were formed in stripes in contact with the p-type GaN contact layer.

The laser fabricated in this manner is an InG
The lifetime was at least 10 times longer than that of the laser without selective regrowth of the aN film. This is probably because the transition density near the active layer was reduced. In addition, the threshold current density is reduced to about 、, which is considered to be because the current narrowing structure is provided in the cladding layer, so that the current can be efficiently narrowed in the vicinity of the active layer.

In this embodiment, an example has been described in which a light emitting portion is provided above a portion not covered with the growth suppressing film.
The insulating growth inhibiting film, SiO ₂ or metal nitride oxide other than SiN or the like, nitride compound semiconductor is not largely dependent on the material as long as an insulating film which does not directly epitaxially grown. (Embodiment 2) In this embodiment, an example in which a laser is manufactured using a metal as a growth suppressing film will be described.

As in the first embodiment, after growing the n-type GaN layer,
The substrate is taken out from the growth device, and the lower GaN
After forming a 2.5-μm-wide molybdenum (Mo) film in the form of stripes at 5 μm intervals in the 1-100> direction, the substrate is returned into the crystal growth apparatus, and the InGa having a thickness of about 0.2 μm is formed.
After regrowing N, n-type AlGaN having a thickness of about 0.4 μm
Other layers including the cladding layer were grown, and the structure shown in FIG. In this structure, an electrode was formed in a stripe shape in contact with the p-type GaN contact layer on a portion not covered with the growth suppressing film.

The laser fabricated in this manner is made of AlG
Compared with the laser without the selective regrowth of the aN film, the lifetime was more than 10 times longer and the threshold current density was reduced to about 1/2. This is because the effective refractive index of the light propagation layer changes due to the reduction of the transition density near the active layer and the disposition of the metal layer in the n-type AlGaN cladding layer, and the lateral (parallel to substrate) direction. This is considered to be because light confinement became conspicuous. In addition, as a metal growth suppression film,
Other than Mo, Pt, W, Ti, Ni, Al, Pd, Au
For example, if the nitride compound semiconductor is a metal that does not directly grow epitaxially, it does not largely depend on the material. (Embodiment 3) In this embodiment, an example will be described in which a metal is used as a growth suppressing film, the surface thereof is nitrided to make it insulating, and then regrown to produce a laser.

After growing the n-type GaN layer in the same manner as in Examples 1 and 2, the substrate was taken out of the growth apparatus, and 2.5 μm of the underlying GaN was placed at 5 μm intervals in the <1-100> direction.
After the titanium (Ti) film is formed in a stripe shape and the substrate is returned to the crystal growth apparatus again, the Ti surface is nitrided for a certain time in an ammonia atmosphere to form a TiN film. Then, again, in the same manner as in Examples 1 and 2, the thickness is reduced to about 0.1 mm.
After regrowth of 2 μm InGaN, a thickness of about 0.4 μm
Another layer including the n-type AlGaN cladding layer was grown, and the structure shown in FIG. In this structure, p-type G
Electrodes were formed in a stripe shape in contact with the aN contact layer.

The life of the laser device manufactured in this manner was at least ten times longer than that of the laser without selective regrowth of the InGaN film. This is probably because the transition density near the active layer was reduced. Further, the threshold current density was reduced to about 1/3. This is an n-type AlGa
By arranging the metal layer in the N clad layer, the effective refractive index of the light propagation layer changed, the confinement of light in the lateral direction (parallel to the substrate) became remarkable, and the metal surface was nitrided. This is considered to be due to the fact that the current becomes an insulator and a current canopy structure is formed. In addition, as a growth suppressing film formed by nitriding the metal surface, in addition to Ti, W, M
As long as a metal nitride such as o, Ni, Al or the like, on which a nitrogen compound semiconductor is not directly epitaxially grown, is formed, it can be used without any problem. (Embodiment 4) In this embodiment, another example in which a laser is manufactured using a metal as the growth suppressing film will be described with reference to FIGS.

As in the first and second embodiments, a buffer layer 502 is grown on a substrate 501, an n-type GaN film (503) is grown to about 4 μm, and then an n-type Al _0.15 Ga _0.85
N (504) is grown 0.7 μm, followed by a GaN light propagation layer (505), an InGaN active layer (506), a carrier block layer (507), and a p-type GaN light propagation layer (508).
To form Furthermore, a p-type Al made of Al _0.15 Ga _0.85 N
After growing the GaN cladding layer (509) by about 0.15 μm, the growth of the nitride compound semiconductor is stopped once, the substrate is taken out from the growth apparatus, and the lower AlGaN is <1-1.
A growth suppressing film (510) of molybdenum (Mo) having a width of 2.5 μm is formed in stripes at intervals of 5 μm in the direction 00>. Thereafter, the substrate is returned to the crystal growth apparatus, and a p-type InGaN regrowth layer (511) having a thickness of about 0.4 μm is regrown. Then, a p-type GaN contact layer (512) is grown to convert the substrate into a crystal growth apparatus. Then, the structure shown in FIG. 5 was manufactured through an element forming process. 513 is an n-type contact electrode, 514 is an insulating film, and 515 is a p-type contact electrode. In this structure, a p-type contact electrode (515) was formed in a stripe shape in contact with the p-type GaN contact layer on a portion not covered with the growth suppressing film.

The lifetime of the laser device manufactured in this manner was reduced to about half the threshold current density as compared with a laser without selective growth of an InGaN film. This is
By disposing the metal layer and the InGaN layer in the cladding layer of the type AlGaN, the effective refractive index of the light propagation layer changes,
This is probably because light confinement in the lateral direction (parallel to the substrate) became significant. (Embodiment 5) In this embodiment, an example in which a laser is manufactured using an amorphous silicon growth suppressing film will be described with reference to FIG. As in Examples 1 and 2, the substrate (60
1) A buffer layer (602) and an n-type GaN layer (60)
3) After the growth, the substrate is taken out from the growth apparatus, and the G
A growth suppression film of amorphous silicon (60 μm) having a width of 2.5 μm at intervals of 5 μm in the <1-100> direction with respect to aN
4) is formed in a stripe shape. Thereafter, the substrate is returned into the crystal growth apparatus, and an InGaN regrown layer (605) having a thickness of about 0.2 μm is regrown. Then, an n-type AlGaN cladding layer (606) having a thickness of about 0.4 μm and an n-type GaN Light propagation layer (607), InGaN multiple quantum well active layer (60
8), p-type GaN light propagation layer (609), p-type AlGaN
Cladding layer (610), p-type GaN contact layer (61
1) was grown, and the structure shown in FIG. 612 is an n-type contact electrode, 613 is an insulating film, and 614 is a p-type contact electrode. In this structure, the p-type GaN is
A p-type contact electrode (614) was formed in a stripe shape in contact with the contact layer (611).

The life of the laser device manufactured in this manner was ten times or more longer than that of the laser without selective regrowth of the InGaN film. This is probably because the transition density near the active layer was reduced. Also, Al
The multi-mode propagation light in the vertical direction (perpendicular to the substrate) generated between the substrate and the clad layer by leaking from the GaN clad layer is absorbed by the growth suppressing film and the InGaN regrown film (or in the direction of the active layer). ), The laser beam always oscillated in a single mode.

In this embodiment, the example in which the light emitting portion is provided on the portion covered with the growth suppressing film has been described. As a type of the growth suppressing film, other than the amorphous silicon, if the nitride compound semiconductor is a material that does not directly epitaxially grow and absorbs or reflects the emission wavelength of the laser, the characteristics of the laser to be manufactured do not largely depend on the material. (Embodiment 6) In this embodiment, an example in which coating with a growth suppressing film and selective growth are performed a plurality of times will be described.

In the device shown in FIG. 7, a growth suppressing film (704) is formed after growing a substrate (701), a buffer layer (702), and an n-type GaN layer (703), followed by n-type InGa.
The N regrowth layer (705) is selectively grown, and the n-type AlGaN cladding layer (706) is grown, and the n-type GaN light propagation layer (707), the InGaN multiple quantum well active layer (70)
8), p-type GaN light propagation layer (709), p-type AlGaN
The cladding layer (710) is grown, and the growth suppressing film (70) is again formed.
4) is formed, a p-type InGaN layer (705) is regrown, a p-type contact layer (711) is grown, and a laser is produced through processes such as etching and electrode formation. 712 is an n-type contact electrode, 71
3 is an insulating film, and 714 is a p-type contact electrode.

By employing the structure shown in FIG.
In addition to the effect of introducing the growth suppressing film into the n-type cladding layer,
The effect of introducing the growth suppressing film into the mold clad layer appears.
That is, by using one of the n-type layer or the p-type layer as a metal and the other as an insulator, the effects of current confinement and light confinement in both the vertical and horizontal directions can be simultaneously obtained in addition to the reduction of dislocation.

The device shown in FIG.
1), buffer layer (802), n-type GaN layer (803)
After the growth, a growth suppressing film (804a) is formed.
-Type InGaN regrown layer (805) is selectively grown and n-type A
By growing the lGaN cladding layer (806), the n-type G
aN light propagation layer (807), InGaN multiple quantum well active layer (808), p-type GaN light propagation layer (809), p-type A
The lGaN cladding layer (810) is grown, the growth suppressing film (804b) is formed again, and the p-type InGaN layer (811) is formed.
Is regrown, a p-type contact layer 812 is grown, and a laser is produced through processes such as etching and electrode formation. 813 denotes an n-type contact electrode,
814 is an insulating film, and 815 is a p-type contact electrode.

In the structure of FIG. 8, in addition to the reduction of dislocation, the multi-mode is suppressed by using a metal or a material that absorbs or reflects laser light emitted from the active layer as the growth suppressing film (804a) under the n-type cladding. By using a metal or an insulator for the growth suppressing film (804b) in the p-type cladding layer, it is possible to enhance the confinement of light in both the vertical and horizontal directions, or to obtain the effect of current confinement.

Further, in the structure shown in FIG.
2 is a buffer layer, 903 is an n-type GaN layer, 904a and b
Is a growth suppressing film, 905 is an n-type InGaN regrown layer, 90
6 is an n-type AlGaN cladding layer, 907 is an n-type GaN light propagation layer, 908 is an InGaN multiple quantum well active layer, 90
9 is a p-type GaN light propagation layer, 910 is a p-type AlGaN cladding layer, 911 is a p-type GaN contact layer, and 912 is n
913 is an insulating film, 914 is a p-type contact electrode.

In the n-type cladding layer, two growth suppressing films (9
By introducing the elements 04a and 904b), the transition density is further reduced, and an effect equivalent to that of the laser device having the structure shown in FIG. 8 can be obtained.

The above are all examples relating to laser production. In the above embodiment, the nitrogen compound semiconductor crystal is grown exclusively by the MOCVD method. However, a method generally used for growing a semiconductor crystal, such as the MBE method or the HVPE method, can be applied without any problem. Also,
In the case of the MOCVD method, the selective growth of the GaN film is often performed under reduced pressure. However, the InGaN film has high selectivity and is easy to grow in the lateral direction, and the surface flatness and the reduction of crystal defects by the selective growth are easy. is there. Therefore, growth is possible regardless of reduced pressure or normal pressure. In addition, in consideration of crystal defects, the present invention is effective not only for lasers but also for all devices made from nitride semiconductors, such as light emitting diodes (LEDs), light receiving devices, and power devices. (Embodiment 7) In this embodiment, an example in which a laser is manufactured using a GaN substrate and an insulator as a growth suppressing film will be described. 10, 1001 is a GaN substrate, 1002 is a buffer layer, 1003 is an n-type GaN layer,
1004 is a growth suppressing film, 1005 is an InGaN regrown layer, 1006 is an n-type AlGaN cladding layer, 1007 is an n-type GaN light propagation layer, 1008 is an InGaN multiple quantum well active layer, 1009 is a p-type GaN light propagation layer, and 1010 is A p-type AlGaN cladding layer, 1011 is a p-type GaN contact layer, 1012 is an n-type contact electrode, 1013 is an insulating film, and 1014 is a p-type contact electrode.

After growing the n-type GaN layer on the GaN substrate, the substrate is taken out from the growth apparatus, and <1-
After forming a growth suppressing film (1004) of a 2.5 μm wide SiN film in stripes at intervals of 5 μm in the 100> direction, the substrate is returned into the crystal growth apparatus, and InGaN (1005) having a thickness of about 0.2 μm is formed. After regrowth, thickness about 0.4
Another layer including a μm n-type AlGaN cladding layer (1006) was grown, and a structure shown in FIG. 10 was formed through an element forming process. In this structure, an electrode (1014) was formed in a stripe shape in contact with the p-type GaN contact layer (1011) on a portion not covered with the growth suppressing film. Note that the buffer layer (1001) in FIG. 10 may be omitted.

The laser fabricated in this manner is made of InG
The lifetime was at least 20 times longer than that of the laser without selective regrowth of the aN film. This is probably because the transition density near the active layer was reduced. Further, the threshold current density is reduced to about 1/4, which is considered to be because the current narrowing structure is provided in the cladding layer so that the current can be efficiently narrowed in the vicinity of the active layer.

In this embodiment, the example in which the light emitting portion is provided above the portion not covered with the growth suppressing film has been described. The insulating growth inhibiting film, SiO ₂ or metal nitride oxide other than SiN or the like, nitride compound semiconductor is not largely dependent on the material as long as an insulating film which does not directly epitaxially grown. Further, it is also possible to fabricate a laser element on a p-type GaN substrate in the same manner as in this embodiment,
The characteristics are greatly improved as on the N substrate. (Embodiment 8) In this embodiment, an example in which a laser is manufactured using a GaN substrate and a metal as a growth suppressing film will be described.

As in the seventh embodiment, an n-type G
After the growth of the aN layer (1003), the substrate was taken out from the growth apparatus, and 5 μm in the <1-100> direction with respect to the underlying GaN.
at intervals of 2.5 m, a molybdenum (Mo) film (1
004) is formed in a stripe shape, and then the substrate is returned to the inside of the crystal growing apparatus, and the InGaN 1005 having a thickness of about 0.2 μm is formed.
After regrowth, another layer including an n-type AlGaN cladding layer (1010) having a thickness of about 0.4 μm was grown, and a structure shown in FIG. In this structure, an electrode (1014) was formed in a stripe shape in contact with the p-type GaN contact layer (1011) on a portion not covered by the growth suppressing film. Note that the buffer layer (1002) in FIG. 10 may be omitted.

The laser fabricated in this manner is made of InG
The lifetime was at least 10 times longer than that of the laser without selective regrowth of the aN film. This is probably because the transition density near the active layer was reduced. Further, the threshold current density was reduced to about 1/4. This is n-type AlGaN
This is probably because the arrangement of the metal layer in the cladding layer changed the effective refractive index of the light propagation layer, and the confinement of light in the lateral direction (parallel to the substrate) became conspicuous.
In addition, as a metal growth suppressing film, Pt,
As long as the metal such as W, Ti, Ni, Al, Pd, and Au is not directly epitaxially grown on the nitride semiconductor, it does not largely depend on the material. Further, it is also possible to fabricate a laser device on a p-type GaN substrate by the same method as in this embodiment, and the characteristics are greatly improved as on an n-type GaN substrate. (Embodiment 9) In this embodiment, a description will be given of an example in which a metal is used as a growth suppressing film using a GaN substrate, the surface thereof is nitrided to make it insulating, and then regrown to produce a laser.

The GaN substrate (10
01) After growing the n-type GaN layer (1003) on the substrate, the substrate was taken out from the growth apparatus, and the GaN of the lower layer was <1-10
0> direction, at intervals of 5 μm, 2.5 μm titanium (T
i) A film (1004) is formed in a stripe shape, and after returning the substrate to the crystal growth apparatus again, the Ti surface is nitrided for a certain time in an ammonia atmosphere to form a TiN film. Thereafter, the thickness is reduced to about 0.3 in the same manner as in Examples 7 and 8.
After regrowth of 2 μm InGaN (1005), an n-type AlGaN cladding layer (1006) about 0.4 μm thick
Was grown, and the structure shown in FIG. 10 was produced through an element forming process. In this structure, a p-type GaN contact layer (101
An electrode was formed in a stripe shape in contact with 1). Note that the buffer layer (1002) in FIG. 10 may be omitted.

The life of the laser device manufactured in this manner was at least 20 times longer than that of the laser without selective regrowth of the InGaN film. This is probably because the transition density near the active layer was reduced. Further, the threshold current density was reduced to about 1/6. This is an n-type AlGa
By arranging the metal layer in the N clad layer, the effective refractive index of the light propagation layer changed, the confinement of light in the lateral direction (parallel to the substrate) became remarkable, and the metal surface was nitrided. This is considered to be due to the fact that the current becomes an insulator and a current canopy structure is formed. In addition, as a growth suppressing film formed by nitriding the metal surface, in addition to Ti, W, M
As long as a metal nitride such as o, Ni, Al or the like, on which a nitrogen compound semiconductor is not directly epitaxially grown, is formed, it can be used without any problem. Further, it is also possible to fabricate a laser device on a p-type GaN substrate by the same method as in this embodiment, and the characteristics are greatly improved as on an n-type GaN substrate. (Embodiment 10) In this embodiment, FIG. 16 shows an example in which a metal is used as a growth suppressing film using a GaN substrate and the growth suppressing film is regrown in a state where the growth suppressing film is not covered flat, and then a laser is manufactured. Write by reference. As shown in FIG. 16, in the element structure of this embodiment, the metallic growth suppressing film 1604 formed on the lower n-type GaN layer 1603
It is the same as Example 8 and Example 9 except that it is not covered with the type InGaN layer 1605 flat.

The laser device shown in FIG.
601, a buffer layer 1602, an n-type GaN layer 1603,
Growth suppression film 1604, InGaN regrowth layer 1605, n
-Type AlGaN cladding layer 1606, n-type GaN light propagation layer 1607, InGaN multiple quantum well active layer 1608, p-type
GaN light propagation layer 1609, p-type AlGaN cladding layer 1610, p-type GaN contact layer 1611, n-type contact electrode 1612, p-type electrode insulating film 1613, and p-type contact electrode 1614. n-type AlGaN
Metal growth suppressing film 16 provided under cladding layer 1606
Reference numeral 04 denotes a laser element introduced in accordance with the above-described eighth and ninth embodiments in order to obtain an optical confinement effect in the horizontal and transverse modes in the laser element. However, as a result of a detailed study of the device characteristics, it was found that the following effects were obtained in addition to the light confinement effect in the horizontal and lateral modes.

As shown in FIG. 16, at least two metallic growth suppressing films 16 provided below the active layer 1608 are formed.
A current injection gap (width Wp) of the p-type electrode 1614 is provided so as to be located above the S portion which is a gap of No. 04, and the regrown n-type InGaN film 1605 is formed of the metallic growth suppressing film. When it is not covered flat and has a depression, <Effect 1> By having the depression, the active layer 1608 is formed.
Is closer to a quantum wire structure perpendicular to the stripe direction of the p-type electrode 1614 from the multiple quantum well structure,
The threshold current density can be further reduced. <
Effect 2> Regrowth n-type I
The crystal strain of the nitride semiconductor layer formed above the nGaN layer 1605 can be reduced, the crystallinity is not reduced, and the element life can be further extended. <Effect 3> By having the recess, the p-type electrode 1614
This prevents the current injected from the gate from spreading in the horizontal direction, and lowers the threshold current density.

The schematic diagram of FIG. 16 exaggerates and shows the nitride semiconductor layers stacked on the side walls of the depression for the sake of explanation. However, since the thickness of each layer is actually small, it is not necessarily shown in FIG. In most cases, the inside of the depression is not necessarily filled with the nitride semiconductor layer. The effects 1 to 3 described above are more remarkably exhibited as the depth of the depression is deeper.

The metallic growth suppressing film 1604 shown in this example
May be subjected to a treatment such as nitriding and replaced with a growth suppressing film with an insulating film, or replaced with an amorphous growth suppressing film such as Si or Si ₃ N ₄ . The effect obtained by replacing the growth suppressing film is the same as that of the above-described embodiment. In this embodiment, a GaN substrate is used, but a nitride semiconductor (AlGaIn) having any other composition is used.
N) A substrate may be used, or a substrate other than a nitride semiconductor substrate, for example, a heterogeneous substrate on which a nitride semiconductor crystal can be epitaxially grown, such as a sapphire substrate, may be used.

In this embodiment, n is applied from the back side of the GaN substrate.
Although the mold electrode 1612 is formed, an n-electrode may be formed from the same side as the p-type electrode as shown in FIG.

The shape of the depression shown in this embodiment is V-shaped, but may be any other shape, for example, a rectangular shape, a forward mesa, or an inverted mesa. (Embodiment 11) In this embodiment, another example in which a laser is manufactured using a GaN substrate and a metal as a growth suppressing film will be described.

In the same manner as in Examples 7 and 8, on the GaN substrate (1
101), a buffer layer (1102) and an n-type GaN film (1103) are grown to about 4 μm, and then n-type Al _0.15 Ga
_0.85 N (1104) is grown 0.7 μm, followed by GaN
A light propagation layer (1105), an InGaN multiple quantum well active layer (1106), a carrier block layer (1107), and a p-type GaN light propagation layer (1108) are formed. Further Al _0.15
After growing a p-type cladding layer (1109) of Ga _0.85 N to a thickness of about 0.15 μm, the growth of the nitride compound semiconductor is temporarily stopped, the substrate is taken out of the growth apparatus, and the lower AlG
aN in the <1-100> direction at intervals of 5 μm,
Molybdenum (Mo) growth suppressing film (2.5 μm wide) (11
10) is formed in a stripe shape. Thereafter, the substrate is returned into the crystal growth apparatus, and an InGaN regrown layer (1111) having a thickness of about 0.4 μm is regrown. Then, a p-type GaN contact layer (1112) is grown and the substrate is taken out of the crystal growth apparatus. Then, a structure shown in FIG. In this structure, an insulating film (1114) was formed in a stripe shape in contact with the p-type GaN contact layer (1112) on a portion not covered by the growth suppressing film, and an electrode (1115) was formed in the opening. The n-type electrode (1113) is Ga
It was formed on the back surface of the N substrate. The buffer layer 1 in FIG.
102 may be omitted.

The lifetime of the laser device fabricated in this manner was reduced to about one-fourth the threshold current density as compared with a laser without selective growth of an InGaN film. This is
By disposing the metal layer and the InGaN layer in the cladding layer of the type AlGaN, the effective refractive index of the light propagation layer changes,
This is probably because light confinement in the lateral direction (parallel to the substrate) became significant. Further, it is also possible to fabricate a laser device on a p-type GaN substrate by the same method as in this embodiment, and the characteristics are greatly improved as on an n-type GaN substrate. (Embodiment 12) In this embodiment, another example in which a metal is used as a growth suppression film using a GaN substrate, and the growth suppression film is regrown in a state where the growth suppression film is not coated flat, and then a laser is manufactured. 17 will be described. In the device structure of this embodiment, the metallic growth suppressing film 1710 formed on the p-type AlGaN layer 1709 is different from the re-grown p-type InGaN layer 1710.
Example 11 is the same as Example 11 except that it is not covered flat.

The laser device shown in FIG.
701, a buffer layer 1702, an n-type GaN layer 1703,
n-type AlGaN cladding layer 1704, n-type GaN light propagation layer 1705, InGaN multiple quantum well active layer 1706,
Carrier block layer 1707, p-type GaN light propagation layer 17
08, p-type AlGaN cladding layer 1709, growth suppression film 1710, InGaN regrowth layer 1711, p-type GaN contact layer 1712, n-type contact electrode 1713, p-type
It comprises a type electrode insulating film 1714 and a p-type contact electrode 1715. The metallic growth suppressing film 1710 provided on the p-type AlGaN cladding layer 1709 was introduced in accordance with the eleventh embodiment in order to obtain a horizontal transverse mode light confinement effect in the laser device. As a result of the study, it was found that the following effects were obtained in addition to the light confinement effect of the horizontal and transverse modes.

As shown in FIG. 17, at least two metallic film growth suppressing films 171 provided above the active layer 1706
A current injection gap (width Wp) of the p-type electrode 1715 is provided so as to be located above the S portion which is a gap of 0, and
Regrowing the metallic growth suppressing film into a p-type InGaN film 171
1 and not having a flat surface, but having a depression. <Effect> By having the depression, regrown p-type InGa
The crystal strain of the nitride semiconductor layer formed above the N film 1711 can be reduced, the crystallinity is not reduced, and the element life can be further extended.

The schematic diagram of FIG. 17 exaggerates and shows the nitride semiconductor layers stacked on the side walls of the depression for the sake of explanation. However, in actuality, since the thickness of each layer is thin, it is not necessarily shown in FIG. In most cases, the inside of the depression is not necessarily filled with the nitride semiconductor layer. The above-mentioned effect is more remarkably exhibited as the depth of the depression becomes deeper.

The metallic growth suppressing film 171 shown in this embodiment
0 may be subjected to a treatment such as nitriding and replaced with a growth suppressing film with an insulating film, or replaced with an amorphous growth suppressing film such as Si or Si ₃ N ₄ . The effect obtained by replacing the growth suppressing film is the same as that of the above-described embodiment. In this embodiment, a GaN substrate is used.
Nitride semiconductor having any other composition (AlGaI
An nN) substrate may be used, or a substrate other than a nitride semiconductor substrate, for example, a heterogeneous substrate on which a nitride semiconductor crystal can be epitaxially grown, such as a sapphire substrate, may be used.

In the present embodiment, n
Although the mold electrode 1713 is formed, the n-electrode may be formed from the same side as the p-type electrode as shown in FIG.

The shape of the depression shown in this embodiment is V-shaped, but may be any other shape, for example, a rectangular shape, a forward mesa, or an inverted mesa. Embodiment 13 In this embodiment, an example in which a laser is manufactured using an amorphous silicon growth suppressing film will be described with reference to FIG. In FIG. 12, 1201 is a GaN substrate, 1202 is a buffer layer, 1203 is an n-type GaN layer,
Numeral 1204 denotes a growth suppressing film, 1205 denotes an InGaN regrown layer, 1206 denotes an n-type AlGaN cladding layer, 1207 denotes an n-type GaN light propagation layer, 1208 denotes an InGaN multiple quantum well active layer, 1209 denotes a p-type GaN light propagation layer, and 1210 denotes A p-type AlGaN cladding layer, 1211 is a p-type GaN contact layer, 1212 is an n-type contact electrode, 1213 is an insulating film, and 1214 is a p-type contact electrode. As in Examples 7 and 8, the n-type G
After the growth of the aN layer (1203), the substrate was taken out of the growth apparatus, and 5 μm in the <1-100> direction with respect to the underlying GaN.
An amorphous silicon film growth suppressing film (1204) having a width of 2.5 μm is formed in stripes at intervals of. Thereafter, the substrate is returned into the crystal growth apparatus, and an InGaN layer (1205) having a thickness of about 0.2 μm is regrown.
Another layer including a 4 μm n-type AlGaN cladding layer (1206) was grown, and after a device process, a structure shown in FIG. 12 was produced. In this structure, an insulating film (1213) is formed in a stripe shape in contact with the p-type GaN contact layer (1211) on a portion covered with the growth suppressing film, and a p-type electrode (1214) is formed in the opening. . Note that the buffer layer 1202 in FIG. 12 may be omitted.

The life of the laser device manufactured in this manner was at least 20 times longer than that of a laser without selective regrowth of an InGaN film. This is probably because the transition density near the active layer was reduced. Also, Al
The multi-mode propagation light in the vertical direction (perpendicular to the substrate) generated between the substrate and the clad layer by leaking from the GaN clad layer is absorbed by the growth suppressing film and the InGaN regrown film (or in the direction of the active layer). ), The laser beam always oscillated in a single mode.

This embodiment has described the example in which the light emitting portion is provided on the portion covered with the growth suppressing film. As a type of the growth suppressing film, other than the amorphous silicon, if the nitride compound semiconductor is a material that does not directly epitaxially grow and absorbs or reflects the emission wavelength of the laser, the characteristics of the laser to be manufactured do not largely depend on the material. Further, it is also possible to fabricate a laser device on a p-type GaN substrate by the same method as in this embodiment, and the characteristics are greatly improved as on an n-type GaN substrate. (Embodiment 14) In this embodiment, another example in which a laser is manufactured using an amorphous silicon growth suppressing film will be described with reference to FIG.
8 will be described. The device structure of this embodiment is n-type Ga
This is the same as the thirteenth embodiment except that the amorphous Si growth suppressing film 1804 formed on the N layer 1803 is not flatly covered with the regrown n-type InGaN layer 1805 and has a ridge structure.

The laser device shown in FIG.
801, a buffer layer 1802, an n-type GaN layer 1803,
Growth suppression film 1804, InGaN regrowth layer 1805, n
-Type AlGaN cladding layer 1806, n-type GaN light propagation layer 1807, InGaN multiple quantum well active layer 1808, p-type
GaN light propagation layer 1809, p-type AlGaN cladding layer 1810, p-type GaN contact layer 1811, n-type contact electrode 1812, p-type electrode insulating film 1813, and p-type contact electrode 1814. n-type AlGaN
The amorphous silicon growth suppression film 1804 provided under the cladding layer 1806 is used in the first embodiment to obtain a horizontal-lateral mode light confinement effect in the laser device.
3 was introduced. However, as a result of a detailed study of the device characteristics, it was found that the device had an effect other than the single-modal vertical / lateral mode.

As shown in FIG. 18, the growth suppressing film 180 provided below the InGaN multiple quantum well active layer 1808
4 has a depression that is not flatly covered with the regrown n-type InGaN layer 1805, and is located above at least one of the region M1 and the region M2 that is flatly covered with the regrown n-type InGaN layer 1805; When a gap Wp for current injection of the p-type ridge stripe structure is provided. <Effect> Regrowth n-type InGa
The crystal strain of the nitride semiconductor layer formed above the N film 1805 can be reduced, the crystallinity is not reduced, and the element life can be further extended.

In the schematic diagram of FIG. 18, the nitride semiconductor layers stacked on the side walls of the depression are exaggerated for the sake of explanation. However, since the thickness of each layer is actually small, the schematic diagram of FIG. 18 is not necessarily shown in FIG. In most cases, the inside of the depression is not necessarily filled with the nitride semiconductor layer. The above-mentioned effect is more remarkably exhibited as the depth of the depression becomes deeper.

The ratio between the regions M1 and M2 that divide the growth suppressing film (1804) can be arbitrarily set. Although only one growth suppressing film is shown in FIG. 18, in actual manufacturing, a plurality of elements are arranged on one wafer. At this time, if the intervals of the growth suppressing films are made equal, the ratio between M1 and M2 becomes 1: 1.
By changing the interval, the ratio between M1 and M2 can be made arbitrary.

The growth suppressing film 1804 shown in this embodiment is
It may be replaced with a metal, or may be replaced with a growth suppressing film with an insulating film having a metal surface subjected to a treatment such as nitriding. The effect obtained by replacing the growth suppressing film is the same as that of the above-described embodiment. In the present embodiment, Ga
Although an N substrate was used, a nitride semiconductor (AlGaInN) substrate having any other composition may be used, or a heterogeneous substrate on which a nitride semiconductor crystal can be epitaxially grown, such as a substrate other than a nitride semiconductor substrate, for example, a sapphire substrate. A substrate may be used.

In the present embodiment, n
Although the mold electrode 1812 is formed, the n-electrode may be formed from the same side as the p-type electrode as shown in FIG.

The shape of the depression shown in this embodiment is V-shaped, but may be any other shape, for example, a rectangular shape, a forward mesa, or an inverted mesa. (Embodiment 15) In this embodiment, an example in which a GaN substrate is used and a growth suppressing film is coated and selective growth is performed a plurality of times will be described with reference to FIGS. In FIG.
1301 is a GaN substrate, 1302 is a buffer layer, 130
3 is an n-type GaN layer, 1304 is a long suppression film, and 1305 is p-type.
-Type and n-type InGaN regrown layers, 1306 is n-type AlG
aN cladding layer, 1307 is n-type GaN light propagation layer, 13
08 is an InGaN multiple quantum well active layer, 1309 is a p-type GaN light propagation layer, 1310 is a p-type AlGaN cladding layer, 1311 is a p-type GaN contact layer, and 1312 is n
Reference numeral 1313 denotes an insulating film, and reference numeral 1314 denotes a p-type contact electrode. In FIG. 14, 14
01 is a GaN substrate, 1402 is a buffer layer, 1403 is an n-type GaN layer, 1404a and b are growth suppressing films, 1405
Is an n-type InGaN regrowth layer, 1406 is an AlGaN cladding layer, 1407 is an n-type GaN light propagation layer, 1408 is an InGaN multiple quantum well active layer, 1409 is p-type GaN
A light propagation layer; 1410, a p-type AlGaN cladding layer;
11 is a p-type InGaN regrown layer, 1412 is a p-type GaN
Contact layer, 1413 is an n-type contact electrode, 141
4 is an insulating film and 1415 is a p-type contact electrode.

FIGS. 13 and 14 show a GaN substrate (140).
1) After forming an n-type GaN layer (1403) on the substrate after a long time, a growth suppressing film (1404a) is formed, and then an InGaN regrown layer (1405) and an AlGaN cladding layer (1406) are grown, and the n-type GaN light is grown. A propagation layer (1407), an active layer (1408), a p-type GaN light propagation layer (1409), a p-type AlGaN cladding layer (1410) are grown, a growth suppression film (1404b) is formed again, and a p-type InGaN (14
11), and further grown on the p-type contact layer (141).
4) is grown to produce a laser through processes such as etching and electrode formation. Note that the buffer layers 1302 and 1402 in FIGS. 13 and 14 may be omitted.

By employing the structure shown in FIG. 13, the effect of introducing the growth suppressing film into the p-type cladding layer appears in addition to the effect of introducing the growth suppressing film into the n-type cladding layer. That is, when one of the growth suppressing films of the n-type layer or the p-type layer is made of metal and the other is made of an insulating material, both effects of current confinement and light confinement can be obtained in addition to the reduction of dislocation.

In the structure of FIG. 14, in addition to the reduction of the dislocation, n
The growth suppressing film (1404b) on the p-type cladding layer is made of a metal or a material that absorbs or reflects laser light emitted from the active layer, while suppressing the multimode by using a metal for the growth suppressing film (1404a) below the mold cladding. Alternatively, by using an insulator, light confinement can be strengthened, or the effect of current confinement can be obtained.

Further, as shown in FIG. 15, by introducing two layers of growth suppressing films (1504a and 1504b) into the n-type cladding layer, the transition density is further reduced, and the laser device having the structure shown in FIG. The same effect can be obtained.
In FIG. 15, reference numeral 1501 denotes a GaN substrate;
2 is a buffer layer, 1503 is an n-type GaN layer, 1504a
And 1504b are growth suppressing films, and 1505 is InGaN
Regrown layer, 1506: AlGaN cladding layer, 1507
1509 are n-type and p-type light guide layers, 1508 is a multiple quantum well active layer, and 1510 is p-type A
1GaN cladding layer, 1511 is a p-type contact layer, 1
513 is an insulating film, 1512 and 1514 are each n
And p-type electrodes. Here, the buffer layer 150
1 may be omitted. Further, it is also possible to fabricate a laser device on a p-type GaN substrate by the same method as in this embodiment, and the characteristics are greatly improved as on an n-type GaN substrate.

The above are all examples relating to laser production. In the above embodiment, the nitrogen compound semiconductor crystal is grown exclusively by the MOCVD method. However, a method generally used for growing a semiconductor crystal, such as the MBE method or the HVPE method, can be applied without any problem. Also,
In the case of the MOCVD method, the selective growth of the GaN film is often performed under reduced pressure. However, the InGaN film has high selectivity and is easy to grow in the lateral direction, and the surface flatness and the reduction of crystal defects by the selective growth are easy. is there. Therefore, growth is possible regardless of reduced pressure or normal pressure. In addition, in consideration of crystal defects, the present invention is effective not only for lasers but also for all devices made from nitride semiconductors, such as light emitting diodes (LEDs), light receiving devices, and power devices. (Embodiment 16) In this embodiment, the effect of combining the metallic growth suppressing film or the metallic growth suppressing film with an insulating film according to the present invention and a GaN substrate which is an example of a nitride semiconductor substrate will be described.

As a result of a detailed study made by the inventors, when the metallic growth suppressing film is formed on a nitride semiconductor layer (hereinafter, referred to as an underlayer), the metal constituting the growth suppressing film is reduced. It was confirmed that internal diffusion occurred in the underlayer. Such internal diffusion of the metal lowers the crystallinity and lowers the yield. However, internal diffusion can be suppressed to some extent by controlling the deposition temperature when forming the growth suppressing film by vapor deposition and the growth temperature of the nitride semiconductor film to be covered in a later step. Further, in addition to this method, the use of GaN, which is an example of a nitride semiconductor substrate, for the substrate makes it possible to more effectively suppress internal diffusion and improve the yield.

According to the experimental results of the inventors, it was confirmed that metal atoms constituting the growth suppressing film reached the underlayer by spike diffusion via threading dislocations. On the other hand, Ga
The threading dislocation density in the nitride semiconductor film grown on the N substrate is lower than that on a heterogeneous substrate (for example, a sapphire substrate) other than the nitride semiconductor substrate.
Therefore, by using a GaN substrate, threading dislocations can be reduced, and internal diffusion can be more effectively suppressed.

In this embodiment, a GaN substrate has been described, but a nitride semiconductor (Al
GaInN) substrate may be used.

[0085]

As described above, according to the present invention, after a nitride compound semiconductor is manufactured, a growth suppressing film on which a nitride compound semiconductor is not directly grown is formed, and thereafter, a selective growth is performed.
By regrowing a nitrogen compound semiconductor containing n, dislocation is reduced and a film having excellent surface flatness can be manufactured.

Further, when the present invention is applied to a light emitting device such as a laser, a growth suppressing film can be provided in a clad layer close to a light propagation layer. Therefore, the effective refractive index of the light propagation layer is changed, and The threshold current density can be reduced by increasing the confinement of the light in ()). In addition, by using an insulating growth suppressing film, a current confinement structure can be formed. By using a growth suppressing film that absorbs or reflects laser light, multiple modes generated by leaking through the cladding layer can be suppressed. It is possible to do.

[Brief description of the drawings]

FIG. 1 is an example of a laser structure described in this embodiment.

FIG. 2 is a schematic diagram of a crystal growth apparatus used in the present embodiment.

FIG. 3 is an example of selective growth described in the present embodiment.

FIG. 4 is a schematic diagram showing a state of transition near a growth suppressing film.

FIG. 5 is an example of the laser structure described in the present embodiment.

FIG. 6 is an example of the laser structure described in the present embodiment.

FIG. 7 is an example of the laser structure described in the present embodiment.

FIG. 8 is an example of the laser structure described in the present embodiment.

FIG. 9 is an example of the laser structure described in the present embodiment.

FIG. 10 is an example of the laser structure described in the present embodiment.

FIG. 11 is an example of the laser structure described in the present embodiment.

FIG. 12 is an example of the laser structure described in the present embodiment.

FIG. 13 is an example of the laser structure described in the present embodiment.

FIG. 14 is an example of the laser structure described in the present embodiment.

FIG. 15 is an example of the laser structure described in the present embodiment.

FIG. 16 is an example of the laser structure described in the present embodiment.

FIG. 17 is an example of the laser structure described in the present embodiment.

FIG. 18 is an example of the laser structure described in the present embodiment.

[Explanation of symbols]

Reference Signs List 101 sapphire substrate 102 buffer layer 103 n-type GaN layer 104 growth suppression film 105 InGaN regrowth layer 106 n-type AlGaN cladding layer 107 n-type light propagation layer 108 multi-quantum well active layer 109 p-type Light propagation layer 110 p-type AlGaN cladding layer 111 p-type contact layer 112 n-type electrode 113 insulating film 114 p-type electrode 301 substrate 302 buffer layer 303 n-type GaN layer 304 growth suppression film 305 Exposed portion of n-type GaN layer surface 306 InGaN regrown layer 307 InGaN regrown layer completely covered on growth suppression film 308 n-type AlGaN cladding layer 401 Substrate 402 Low temperature buffer layer 403 GaN film 404 SiO ₂ growth suppression film 405: In _0.1 Ga _0.9 N film 406: Al _0.15 Ga _0.85 N film 4 07: transition generated from the substrate interface 501: substrate 502: buffer layer 503: n-type GaN film 504: n-type Al _0.15 Ga _0.85 N clad layer 505: n-type GaN light propagation layer 506: InGaN active layer 507: carrier block layer 508: p-type GaN light propagation layer 509: p-type Al _0.15 Ga _0.85 N cladding layer 510: growth suppression film 511: p-type InGaN regrowth layer 512: p-type GaN contact layer 513: n-type contact electrode 514: insulating film 515 ... p-type contact electrode 601 ... substrate 602 ... buffer layer 603 ... n-type GaN layer 604 ... growth suppression film 605 ... InGaN regrowth layer 606 ... n-type AlGaN cladding layer 607 ... n-type GaN light propagation layer 608 ... InGaN multiple quantum well Active layer 609: p-type GaN light propagation layer 610: p-type AlGaN cladding Layer 611: p-type GaN contact layer 612: n-type contact electrode 613: insulating film 614: p-type contact electrode 701: substrate 702: buffer layer 703: n-type GaN layer 704: growth suppression film 705: InGaN regrown layer 706 ... n-type AlGaN cladding layer 707 ... n-type GaN light propagation layer 708 ... InGaN multiple quantum well active layer 709 ... p-type GaN light propagation layer 710 ... p-type AlGaN cladding layer 711 ... p-type contact layer 712 ... n-type contact electrode 713 ... Insulating film 714 ... p-type contact electrode 801 ... substrate 802 ... buffer layer 803 ... n-type GaN layer 804a ... growth suppressing film 804b ... growth suppressing film 805 ... n-type InGaN regrowth layer 806 ... n-type AlGaN cladding layer 807 ... n-type GaN light propagation layer 808 ... InGaN multiple quantum well active layer 809 ... p-type GaN light propagation layer 810 ... p-type AlGaN cladding layer 811 ... p-type InGaN layer 812 ... p-type contact layer 813 ... n-type contact electrode 814 ... insulating film 815 ... p-type contact electrode 901 ... substrate 902 ... buffer layer 903: n-type GaN layer 904a ... is a growth suppressing film 904b ... is a growth suppressing film 905 ... n-type InGaN regrowth layer 906 ... n-type AlGaN cladding layer 907 ... n-type GaN light propagation layer 908 ... InGaN multiple quantum well active layer 909 ... p-type AlGaN cladding layer 910 ... p-type GaN light propagation layer 911 ... p-type GaN contact layer 912 ... n-type contact electrode 913 ... insulating film 914 ... p-type contact electrode 1001 ... GaN substrate 1002 ... buffer layer 1003 ... n-type GaN Layer 1004: Growth suppression film 1005: InGaN layer Long layer 1006 n-type AlGaN cladding layer 1007 n-type GaN light propagation layer 1008 InGaN multiple quantum well active layer 1009 p-type GaN light propagation layer 1010 p-type AlGaN cladding layer 1011 p-type GaN contact layer 1012 n -Type contact electrode 1013-insulating film 1014-p-type contact electrode 1101-GaN substrate 1102-buffer layer 1103-n-type GaN film 1104-n-type Al _0.15 Ga _0.85 N cladding layer 1105-GaN light propagation layer 1106-InGaN multiple quantum well Active layer 1107 Carrier block layer 1108 p-type GaN light propagation layer 1109 p-type Al _0.15 Ga _0.85 N cladding layer 1110 growth suppression film 1111 InGaN regrowth layer 1112 p-type GaN contact layer 1113 n-type electrode 1114 ... Insulation film 1 115 ... p-type electrode 1201 ... GaN substrate 1202 ... buffer layer 1203 ... n-type GaN layer 1204 ... growth suppression film 1205 ... InGaN regrowth layer 1206 ... n-type AlGaN cladding layer 1207 ... n-type GaN light propagation layer 1208 ... InGaN multiple quantum Well active layer 1209 p-type GaN light propagation layer 1210 p-type AlGaN cladding layer 1211 p-type GaN contact layer 1212 n-type contact electrode 1213 insulating film 1214 p-type contact electrode 1301 GaN substrate 1302 buffer layer 1303 ... n-type GaN layer 1304a ... growth suppression film 1304b ... growth suppression film 1305 ... InGaN regrowth layer 1306 ... n-type AlGaN cladding layer 1307 ... n-type GaN light propagation layer 1308 ... InGaN multiple quantum well active layer 1309 ... p-type GaN light Biography Layer 1310: p-type AlGaN cladding layer 1311: p-type GaN contact layer 1312: n-type contact electrode 1313: insulating film 1314: p-type contact electrode 1401: GaN substrate 1402: buffer layer 1403: n-type GaN layer 1404a: growth suppressing film 1404b: Growth suppression film 1405: n-type InGaN regrowth layer 1406 ... n-type AlGaN cladding layer 1407 ... n-type GaN light propagation layer 1408 ... InGaN multiple quantum well active layer 1409 ... p-type GaN light propagation layer 1410 ... p-type AlGaN cladding Layer 1411 p-type InGaN regrowth layer 1412 p-type GaN contact layer 1413 n-type contact electrode 1414 insulating film 1415 p-type contact electrode 1501 GaN substrate 1502 buffer layer 1503 n-type GaN layer 1504a Growth suppression film 1504b growth suppression film 1505 InGaN regrown layer 1506 n-type AlGaN cladding layer 1507 n-type light guide layer 1508 multi-quantum well active layer 1509 p-type light guide layer 1510 p-type AlGaN cladding layer 1511 ... p-type contact layer 1512 ... n-type contact electrode 1513 ... insulating film 1514 ... p-type contact electrode 1601 ... GaN substrate 1602 ... buffer layer 1603 ... n-type GaN layer 1604 ... growth suppression film 1605 ... InGaN regrowth layer 1606 ... n-type AlGaN cladding layer 1607 n-type GaN light propagation layer 1608 InGaN multiple quantum well active layer 1609 p-type GaN light propagation layer 1610 p-type AlGaN cladding layer 1611 p-type GaN contact layer 1612 n-type contact electrode 1613 insulation 1614 ... p-type contact electrode S ... Interval Wp ... current growth inhibiting film infusion gap 1701 ... GaN substrate 1702 ... buffer layer 1703 ... n-type GaN film 1704 ... n-type Al _0.15 Ga _0.85 N cladding layer 1705 ... GaN light propagation layer 1706 ... InGaN multiple quantum well active layer 1707 carrier block layer 1708 p-type GaN light propagation layer 1709 p-type Al _0.15 Ga _0.85 N cladding layer 1710 growth suppression film 1711 InGaN regrowth layer 1712 p-type GaN contact layer 1713 ... n-type electrode 1714 ... insulating film 1715 ... p-type electrode 1801 ... GaN substrate 1802 ... buffer layer 1803 ... n-type GaN layer 1804 ... growth suppression film 1805 ... InGaN regrowth layer 1806 ... n-type AlGaN cladding layer 1807 ... n-type GaN Light propagation layer 1808 ... In aN multiple quantum well active layer 1809 p-type GaN light propagation layer 1810 p-type AlGaN cladding layer 1811 p-type GaN contact layer 1812 n-type contact electrode 1813 insulating film 1814 p-type contact electrode M: growth suppression film Width M1: Width of the portion where the growth suppressing film is covered by the regrown n-type InGaN layer M2: Width of the portion where the growth suppressing film is covered by the regrown n-type InGaN layer Wp: Current injection gap

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Jun Ogawa 22-22 Nagaikecho, Abeno-ku, Osaka City, Osaka Inside (72) Inventor Yuzo Tsuda 22-22 Nagaikecho, Abeno-ku, Osaka City, Osaka (72) Inventor Masahiro Araki 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka

Claims (8)

[Claims] In a semiconductor light emitting device having a substrate, a nitride compound semiconductor layer, a growth suppressing film formed on a part of the surface of a nitride compound semiconductor layer, a regrowth layer and an active layer, the regrowth layer is a nitrogen compound. A semiconductor light emitting device formed on a semiconductor layer and a growth suppressing film, wherein the semiconductor light emitting device contains In. 2. The growth control film according to claim 1, wherein the growth suppression film has a stripe-shaped lacking portion, and the effective refractive index at a position corresponding to the stripe lacking portion is made higher than the periphery of the stripe lacking portion. 2. The semiconductor light emitting device according to claim 1, wherein laser oscillation is caused at a position corresponding to (1). 3. The semiconductor light emitting device according to claim 1, wherein the growth suppressing film has a stripped portion and at least partially includes an insulating film. 4. The method according to claim 1, wherein the growth suppressing film is formed vertically below the laser stripe and is made of a material that absorbs or reflects light generated in the active layer. The semiconductor light emitting device according to any one of the above. 5. The semiconductor light emitting device according to claim 1, wherein said growth suppressing film is formed between said substrate and said active layer. 6. The active layer is formed above the regrowth layer, the regrowth layer has a concave portion at a position corresponding to the lacking portion of the growth suppressing film, and the active layer follows the uneven shape of the regrown layer. The semiconductor light emitting device according to claim 1, wherein the semiconductor light emitting device is formed. 7. The active layer is formed above the regrown layer, the regrown layer has a concave portion at a position corresponding to the growth suppressing film, and the active layer is formed along the unevenness of the regrown layer. The semiconductor light emitting device according to claim 1, wherein: 8. A method for manufacturing a nitride semiconductor layered structure, comprising: forming a first nitride semiconductor; forming a growth suppression film on a part of the surface of the first nitride semiconductor; Starting the formation of a nitrogen compound semiconductor containing In from the surface of the nitrogen compound semiconductor where no is formed.