JP2002324913A - Iii nitride semiconductor and method of manufacturing the same, and semiconductor device and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a III nitride semiconductor which has higher carrier concentration and higher quality than the conventional one. SOLUTION: On a sapphire substrate 10, a low-temperature GaN buffer layer 11 and a p-type Alx Ga(1-x) N (0<=x<=1) layer 12 as the III nitride semiconductor are stacked in this order. The p-type Alx Ga(1-x) N (0<=x<=1) layer 12 is, for example, a p-type Al0.08 Ga0.92 N layer where x=0.08. The p-type Al0.08 Ga0.92 N layer 12 includes Mg(magnesium) which is a p-type impurity and B(boron), each in a quantity of about 8×10<19> cm<-3> .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a group III nitride semiconductor used for a light source for an optical pickup such as a DVD or a CD, a writing light source for an electrophotography, a light source for an optical communication, an ultraviolet sensor, a high-temperature operating transistor, and the like. The present invention relates to a manufacturing method, a semiconductor device, and a manufacturing method thereof.

[0002]

2. Description of the Related Art Conventionally, a blue LED is a red or green LE.
However, in recent years, in a group III nitride semiconductor represented by the general formula InAlGaN, a low-temperature AlN buffer layer or a low-temperature Ga
Improvements in crystal growth technology using an N buffer layer and a technology to reduce the resistance of a p-type layer that has been increased in resistance by hydrogen passivation by heat treatment have been found.
Has been put to practical use.

After that, further improvement in crystallinity and p-type Ga
Research into lowering the resistance of N has progressed, and various proposals have been made, and a purple semiconductor laser that has low output (several mW) but continuously oscillates near room temperature has been put to practical use.

As described above, in developing a group III nitride semiconductor device, a technique for producing a p-type group III nitride is an important basic technique.

Since the p-type group III nitride combines p-type impurities with hydrogen and inactivates the p-type impurities, crystal growth in an atmosphere containing hydrogen, gas in a hydrogen gas or a gas generating hydrogen. When heat treatment is performed in the inside, the resistance is increased. Therefore, in a method such as MOCVD using hydrogen as a carrier gas, it is difficult to produce a p-type group III nitride as-grown (as-grown without special post-treatment such as heat treatment). there were.

[0006] As a method for producing a p-type group III nitride, a first production method in which a special treatment is applied to a high resistance group III nitride to make it p-type, and a crystal growth step are devised. By doing so, the method is roughly divided into a second manufacturing method of manufacturing a p-type group III nitride.

In the above-mentioned first manufacturing method, Japanese Patent Application Laid-Open No. Hei 5-183189 (hereinafter referred to as "prior art 1") discloses a special treatment for p-type conversion. There has been proposed a method in which a heat treatment is performed in an atmosphere gas containing no (NH ₃ or the like), and a part of hydrogen contained in the crystal is diffused and discharged out of the crystal to make a p-type with low resistance.

[0008] Alternatively, Japanese Unexamined Patent Publication No. Hei 3-218625 (hereinafter referred to as prior art 2) discloses that a low-energy electron beam is irradiated to cut off the bond between hydrogen contained in a crystal and a p-type impurity, thereby forming a low-resistance p-type impurity. A way to type has been proposed.

In the above-mentioned second manufacturing method, a method of devising a crystal growth process is disclosed in Japanese Patent Application Laid-Open No.
No. 22 (hereinafter referred to as prior art 3) discloses a method of performing a cooling process after completion of crystal growth in a gas atmosphere containing no hydrogen such as nitrogen or an inert gas to thereby provide a low-resistance p-type. It has been disclosed.

[0010] A method of performing crystal growth in a system containing no hydrogen gas has also been adopted. This is an MOCVD method using nitrogen as a carrier gas or an MBE method using a raw material containing no hydrogen. In these methods, as-grow
It is known that p-type GaN can be obtained in the state of n (in a state where a crystal is grown only and a special treatment for p-type conversion is not performed).

Another method is disclosed in Japanese Patent Application Laid-Open No. 6-232 / 1994.
451 No. (hereinafter, prior referred art 4) in, an In _x Al _y
After growing a group III nitride layer represented by Ga _(1-xy) N, (0 <x <1, 0 ≦ y <1), Mg was added to 1 × 10 ¹⁷
doping in the range of cm ^{−3 to} 3 × 10 ²⁰ cm ⁻³ and p-type
A method for manufacturing a group III nitride semiconductor is disclosed.

This method uses In _x Al _y Ga _(1-xy) N,
By using the (0 <x <1, 0 ≦ y <1) layer as the buffer layer, the strain of the p-type GaN layer grown thereon is relaxed to prevent the crystallinity from deteriorating. This is for producing p-type GaN. According to this method,
GaN is doped with Mg at 3 × 10 ²⁰ cm ⁻³ and 5 ×
A p-type GaN having a carrier concentration of 10 ¹⁷ cm ^-3 is manufactured.

At present, a p-type group III nitride semiconductor is manufactured by the above method.

A high carrier concentration is required for a p-type group III nitride semiconductor used for a light emitting device or the like that requires a high current density. The carrier concentration is low even if it is made p-type by the method. For example, it is not easy to produce AlGaN used for a cladding layer of a semiconductor laser with a carrier concentration exceeding 10 ¹⁷ cm ⁻³ .

As a method for solving this problem, Japanese Patent Laid-Open No.
No. 101496 (hereinafter referred to as prior art 5) discloses that Mg
GaN and Si at a ratio of 2: 1, Mg and O at a ratio of 2: 1, Be and Si at a ratio of 2: 1, or Be and O at a ratio of 2: 1 to GaN at a ratio of about 10 ¹⁹ cm ⁻³ to 10 ²⁰ cm ^−3. A method for producing p-type GaN having a high carrier concentration by co-doping is disclosed.

Further, a method of increasing the effective carrier concentration by a GaN / AlGaN superlattice structure has been proposed, and a semiconductor laser using the same in a cladding layer has been manufactured.

FIG. 19 is Japanese Patent Application Laid-Open No.
2 shows a semiconductor laser shown in Prior Art 6).
FIG. Referring to FIG. 19, this semiconductor laser
Combination of selective growth and lateral growth on sapphire substrate
The GaN thick film grown on the sapphire substrate
On the fabricated GaN substrate 160, formed of n-type GaN
Second buffer layer 161, n-type In_0.1Ga_0.9N
Crack preventing layer 162, n-type Al_0.2Ga_0.8N /
N-side cladding layer 163 of GaN superlattice, n-type Ga
N-side light guide layer 164 made of N_0.05Ga_0.95N
/ In_0.2Ga_{0 .8}An active layer 165 having an N multiple quantum well structure;
p-type Al_0.3Ga_0.7A p-side cap layer 166 made of N;
p-side light guide layer 167 made of p-type GaN, p-type Al
_0.2Ga_0.8P-side cladding layer 1 made of N / GaN superlattice
68, the p-side contact layer 169 made of p-type GaN is
Next, they are laminated to form a laminated structure.

Then, a part of the p-side contact layer 169 and a part of the p-side cladding layer 168 are dry-etched to have a width of 4 μm.
m ridge stripes are formed. A p-side electrode 170 is formed on the ridge stripe, and the n-type GaN substrate 1
The n-side electrode 171 is formed on the back surface of the electrode 60. The end face of the laser resonator is formed by cleaving the M-plane of the n-type GaN substrate 160.

Here, the p-type cladding layer 168 is a carrier.
GaN and Al with high concentration_0.2Ga_{0 .8}Superlattice structure with N
To increase the effective carrier concentration
ing.

[0020]

As described above, since it is difficult to produce a low-resistance p-type group III nitride semiconductor, a high-intensity blue light emitting diode using a group III nitride semiconductor and a low output ( Only a few mW) of a violet semiconductor laser has been put into practical use.
No light emitting diode or semiconductor laser that emits light in the ultraviolet region shorter than 00 nm, or a practical light receiving element having sensitivity characteristics in the ultraviolet wavelength region has been put to practical use.

For example, in the case of a semiconductor laser, since the resistance of the p-type cladding layer and the contact resistance of the p-side ohmic electrode are still high, the operating voltage is increased and heat is generated at the time of a large current operation. Has not been put to practical use. Further, in the case of a light emitting element or a light receiving element used in the ultraviolet wavelength region, the resistance increases as the Al composition ratio of the p-type AlGaN layer increases, so that a light emitting element or a light receiving element in the ultraviolet wavelength region has been put to practical use. Not.

Also, low-output violet semiconductor lasers that have been put into practical use have high manufacturing costs.

Hereinafter, the problems of the prior art will be described.

In the method of converting a group III nitride semiconductor into a p-type semiconductor according to the prior art 1, since hydrogen that inactivates a p-type impurity is discharged to the outside of the crystal by heat treatment, an atmosphere containing no hydrogen, generally Is heat-treated in a nitrogen gas atmosphere. However, in this atmosphere, nitrogen gas composed of nitrogen molecules does not become a raw material for forming group III nitrides, so at high temperatures exceeding 700 ° C., the crystal surface is decomposed and the surface resistance is increased. Sometimes occurred. This may cause a problem such as an increase in ohmic contact resistance when an electrode is formed on the crystal surface. Further, since a heat treatment step for p-type conversion is required, an increase in the number of manufacturing steps and heat treatment equipment are required, and the cost is industrially high.

The prior art 3 does not require a heat treatment step, so that the cost can be reduced. However, the temperature is lowered from a crystal growth temperature of about 1000 ° C. to room temperature in an atmosphere containing only nitrogen gas or an inert gas. Therefore, similar to the prior art 1,
In some cases, the crystal surface is decomposed, and the characteristics are degraded, for example, the surface resistance is increased.

In the low energy electron beam irradiation of the prior art 2, since the penetration depth of the electron beam is shallow, the p-type can be formed only in the vicinity of the crystal surface, and the area where the electron beam can be irradiated at a time is narrow, so that It takes time to make the entire surface p-type, and it is industrially too costly.

The method of the prior art 4, that is, _Inx
After growing a group III nitride layer represented by Al _y Ga _(1-xy) N, (0 <x <1, 0 ≦ y <1),
Doping in the range of ¹⁷ cm ^-3 to 1 × 10 ²⁰ cm ^-3
In the method of producing the type GaN, the distortion of the crystal layer immediately above is relaxed, and the p-type characteristic is exhibited. However, when a multilayer structure is formed, the effect is reduced as the layer thickness increases.
Therefore, there is a problem that the degree of freedom in device design is small. Furthermore, in the case of AlGaN, as-grow
With n, it is difficult to obtain one having a high carrier concentration, and post-treatment such as heat treatment is still necessary.

Regarding the crystal growth method in an atmosphere containing no hydrogen, first, in the MBE method, since crystal growth is performed in a high vacuum, defects are formed due to dissociation of nitrogen. . In addition, there is a problem in supply of nitrogen, the growth rate is low, and it is not suitable for mass production as in the MOCVD method.

On the other hand, when a crystal is grown by MOCVD in an atmosphere containing as little hydrogen as possible, as in the MBE method,
In an experiment on GaN by the inventor of the present application, only those having severe surface irregularities could be grown, and those having good crystallinity could not be grown. That is, it is considered that the conditions for growing high-quality p-type GaN in an atmosphere containing no hydrogen are narrow.

Further, the method of the prior art 5, that is, Mg
And Si in a ratio of 2: 1 or Mg and O in a ratio of 2: 1, Be and Si in a ratio of 2: 1, or Be and O in a ratio of 2: 1 and a ratio of 10 ¹⁹ cm ⁻³ to 10 ²⁰ cm ^{−3 in} GaN. In the method of producing p-type GaN having a high carrier concentration by doping at about the same level, as the doping amount increases, the surface morphology deteriorates, and thus a device such as a semiconductor laser that requires a flat waveguide structure is produced. Had difficulty.

In the semiconductor laser of the prior art 6, p
Although the carrier concentration of the p-type cladding layer is effectively increased by using a type Al _0.2 Ga _0.8 N / GaN superlattice, a crystal growth process and an apparatus for producing a superlattice structure are required. In addition, the time required for crystal growth and the equipment cost are increased, and the semiconductor laser becomes expensive.

The carrier concentration of p-type GaN is 10 ¹⁸
Because cm ^-3 or less and not high enough, p-type Al _0.2 Ga _0.8 N
The effective carrier concentration of the / GaN superlattice is not sufficient for practical use of a high-power semiconductor laser, and p-type AlGaN having a high carrier concentration is required.

An object of the present invention is to solve the above-mentioned problems of the prior art. That is, an object of the present invention is to provide a group III nitride semiconductor having a higher carrier concentration and a higher quality than in the past, a method for manufacturing the same, a semiconductor device, and a method for manufacturing the same.

[0034]

In order to achieve the above-mentioned object, the present invention according to claim 1 is directed to a p-type Al to which Mg is added.
_{In x} Ga _(1-x) N (0 ≦ x ≦ 1), the p-type Al _x
Ga _(1-x) N (0 ≦ x ≦ 1) is characterized in that B is added simultaneously with Mg.

According to a second aspect of the present invention, there is provided a semiconductor laminated structure including the group III nitride semiconductor according to the first aspect.

According to a third aspect of the present invention, in the semiconductor device according to the second aspect, the group III nitride semiconductor according to the first aspect is used for a contact layer for forming a p-side ohmic electrode.

According to a fourth aspect of the present invention, in the semiconductor device according to the second or third aspect, the semiconductor device is a semiconductor light emitting element.

According to a fifth aspect of the present invention, in the semiconductor device according to the fourth aspect, the semiconductor light emitting element is a semiconductor laser element.

According to a sixth aspect of the present invention, in the semiconductor device according to the fourth or fifth aspect, the semiconductor light emitting element has an emission wavelength of 400 nm or less.

According to a seventh aspect of the present invention, in the semiconductor device according to the fifth aspect, the semiconductor laser element as the semiconductor device includes at least one of the group III nitride semiconductors according to the first aspect used for a cladding layer. It is characterized by having a pn junction.

The invention according to claim 8 is characterized in that p-type Al _x Ga _(1-x) N (0 ≦ x ≦
The method 1) is characterized in that crystal is grown in a reaction system containing hydrogen gas, and cooling from the crystal growth temperature immediately after the crystal growth is performed in a cooling atmosphere containing a nitrogen source.

According to a ninth aspect of the present invention, in the method of manufacturing a group III nitride semiconductor according to the eighth aspect, the nitrogen source contained in the cooling atmosphere is NH ₃ .

The tenth aspect of the present invention is directed to a p-type Al _x Ga _(1-x) N (0 ≦ x
.Ltoreq.1), a crystal is grown in a reaction system containing hydrogen gas, and cooling from the crystal growth temperature immediately after the crystal growth is performed in an NH ₃ cooling atmosphere.

The eleventh aspect of the present invention relates to a p-type Al _x Ga _(1-x) N (0 ≦ x ₎ to which B is added simultaneously with Mg.
The semiconductor stacked structure including ≦ 1) is crystal-grown in a reaction system containing hydrogen gas, and cooling from the crystal growth temperature immediately after the crystal growth is performed in an atmosphere containing a nitrogen source.

The twelfth aspect of the present invention is the first aspect of the present invention.
1. The method for manufacturing a semiconductor device according to item 1, wherein the nitrogen source contained in the cooling atmosphere is NH ₃ .

The thirteenth aspect of the present invention is directed to a p-type Al _x Ga _(1-x) N (0 ≦ x
The semiconductor stacked structure including ≦ 1) is crystal-grown in a reaction system containing hydrogen gas, and cooling from the crystal growth temperature immediately after the crystal growth is performed in a cooling atmosphere of NH ₃ .

[0047]

Embodiments of the present invention will be described below with reference to the drawings. The group III nitride semiconductor according to the present invention has M
p-type Al _x Ga _(1-x) N to which g (magnesium) is added
(0 ≦ x ≦ 1), the p-type Al _x Ga _(1-x) N
(0 ≦ x ≦ 1) contains Mg (magnesium) and B
(Boron) is added.

In general, when a p-type group III nitride semiconductor is manufactured, an appropriate amount of a p-type impurity is added to control the carrier concentration. Note that Mg is generally used as the p-type impurity.

However, p in the group III nitride semiconductor
Since the activation rate of the p-type impurity is as low as about 1%, even if the p-type impurity is added up to about 10 ²⁰ cm ⁻³ , only a p-type GaN having a low carrier concentration of 10 ¹⁸ cm ⁻³ or less is produced. Not done.

Further, in the case of a wide gap semiconductor such as AlGaN, the carrier concentration is further reduced and the resistance is increased.

Further, the doping amount of the p-type impurity is
^If it exceeds ²⁰ cm ^-3 , the surface morphology deteriorates, and conversely, the resistance increases.

The p-type impurity (generally Mg is used) added to the Al _x Ga.sub. _(1-x) N (0.ltoreq.x.ltoreq.1) crystal replaces Ga or Al and occupies a group III element site.

However, since Mg has a larger size than Ga and Al, in the AlGaN crystal to which Mg has been added, the difference in the size makes the whole crystal unstable, and the Mg has a force to remove. Acts, so that a high concentration of Mg cannot occupy the group III atom site,
It enters the interstitial location and thus acts as a donor. That is, if Mg is added at a high concentration in order to increase the carrier concentration, the crystallinity deteriorates and the carrier concentration decreases.
l _x Ga _(1-x) N (0 ≦ x ≦ 1) cannot be obtained.

On the other hand, as in the present invention, Al _x Ga grown by adding B (boron) at the same time as Mg is grown.
_(1-x) N (0 ≦ x ≦ 1) does not cause a decrease in carrier concentration even when Mg is added at a high concentration, and a high carrier concentration can be obtained.

The reason is that B, which is smaller in size than Ga and Al, is added simultaneously with Mg,
Instability of the crystal due to g is alleviated, and Mg can enter the group III site. As a result, p-type Al _x Ga _(1-x) N (0 ≦ x ≦ It is considered that 1) is obtained.

If the amount of B added is on the order of 10 ²⁰ cm ^-3 , the band gap and the refractive index of AlGaN do not change so much that Al can be treated as AlGaN.

In the present invention, as a first method of manufacturing a group III nitride semiconductor, p-type Al _x Ga _(1-x) N (0 ≦ x ≦ 1) to which B is added simultaneously with Mg is used. Crystals are grown in a reaction system containing hydrogen gas, and cooling from the crystal growth temperature immediately after the crystal growth is performed in a cooling atmosphere containing a nitrogen source.

Here, the cooling atmosphere is nitrogen, a mixed gas of an inert gas and a nitrogen raw material, or
A mixed gas containing several percent of hydrogen therein, a nitrogen source gas alone, or a mixed gas atmosphere of a nitrogen source gas and hydrogen can be used.

According to the first manufacturing method, Al _x Ga.sub. _(1-x) N having a high carrier concentration by simultaneously adding Mg and B is used.
By combining the crystal growth of (0 ≦ x ≦ 1) and the cooling in the above-described atmosphere gas containing the nitrogen source, the p of Al _x Ga _(1-x) N (0 ≦ x ≦ 1), which has been conventionally difficult, is obtained. Type crystal is a
Obtained by s-grown.

The reason why a p-type crystal can be obtained as-grown is that p-type Al _x G to which Mg and B are simultaneously added.
a _(1-x) N (0 ≦ x ≦ 1) is obtained by growing a carrier having a high carrier concentration, and performing cooling from the crystal growth temperature in the above-described cooling atmosphere. This is presumably because diffusion into the crystal is suppressed and resistance increase due to hydrogen passivation is prevented. Al _x Ga _(1-x) N
In the case where (0 ≦ x ≦ 1) is crystal-grown on the outermost surface of a single layer or a laminated structure, the nitrogen source contained in the cooling atmosphere further generates atomic nitrogen contributing to the formation reaction of AlGaN. Therefore, the dissociation of nitrogen from the surface of the AlGaN crystal is prevented, and as a result, the generation of nitrogen vacancies serving as donor defects is suppressed, the surface is prevented from increasing in resistance, and the low-resistance p-type Al _x Ga _(1-x) N (0 ≦ x ≦ 1) is a
It is thought to be obtained by s-grown.

When hydrogen is contained in the atmosphere gas during cooling, an unreacted organic raw material adsorbed on the crystal surface and a cleaning effect by the organic hydrogen can be expected. Can be prevented from increasing.
This is an effect that cannot be obtained by the prior art.

The nitrogen source gas is not particularly limited. However, by using a compound such as NH ₃ which generates hydrogen by its decomposition, the effect of suppressing decomposition of the crystal surface by atomic nitrogen (diffusion of hydrogen thereby) is reduced. Suppression effect) and the cleaning effect by hydrogen can be obtained at the same time.

According to the above-described prior art 1, in an atmosphere containing a compound that generates hydrogen or a hydrogen gas, a high resistance II
Since it is difficult to make the p-type by discharging hydrogen from the group I nitride, the heat treatment was performed in an atmosphere containing no hydrogen. On the other hand, in the manufacturing method of the present invention, immediately after the crystal growth, Low resistance p-type Al _x Ga _(1-x) N (0 ≦ x ≦ 1)
By suppressing the diffusion and intrusion of hydrogen into the inside, it is possible to suppress the increase in resistance in the cooling process after crystal growth, and to reduce the p-type Al of low resistance.
and characterized by producing _{x Ga (1-x) N} (0 ≦ x ≦ 1), the prior art is different in principle. Further, the atmosphere differs from the prior art in that hydrogen may or may not contain hydrogen, and when hydrogen is contained, the effect of hydrogen is actively utilized.

That is, p-type Al _x Ga _(1-x) N to which B (boron) is added simultaneously with Mg (magnesium).
In the manufacturing method (0 ≦ x ≦ 1), NH ₃ (ammonia) can be used as the nitrogen source contained in the cooling atmosphere.

When NH ₃ is used as the nitrogen source gas, the effect of suppressing the decomposition of the crystal surface by atomic nitrogen generated by the decomposition and the effect of cleaning by hydrogen are simultaneously obtained.

In the present invention, as a second method for manufacturing a group III nitride semiconductor, p-type Al _x Ga.sub. _(1-x) N (0.ltoreq.x.ltoreq.1 ₎ to which B is added simultaneously with Mg is used. In this case, the crystal is grown in a reaction system containing hydrogen gas, and cooling from the crystal growth temperature immediately after the crystal growth is performed in a cooling atmosphere of NH ₃ .

In the second manufacturing method, since the atmosphere during cooling is only NH ₃ gas, the effect of suppressing the decomposition of the crystal surface by the atomic nitrogen generated by the decomposition and the effect of cleaning by hydrogen can be reduced. Can be more effectively obtained.

Conventionally, in a heat treatment in an NH ₃ atmosphere, the resistance of a p-type crystal is increased by hydrogen passivation,
Although a low-resistance p-type group III nitride was not obtained, in the present invention, the atmosphere was changed to NH ₃ during the cooling process after crystal growth.
By using gas, low-resistance p-type Al _x Ga _(1-x) N (0 ≦ x ≦ 1) in which surface deterioration is suppressed is as-grown.
n.

In the present invention, p-type Al _x Ga.sub. _(1-x) N (0.ltoreq.x.ltoreq.1 ₎ to which the above-mentioned group III nitride semiconductor (B (boron) is added simultaneously with Mg (magnesium)) is used. )
A semiconductor device having a semiconductor multilayer structure including

Note that such a semiconductor device is a p-type Al
long as it functions with the properties of the _{x Ga (1-x) N} (0 ≦ x ≦ 1), can take any device embodiment. That is, it can take the form of a semiconductor light emitting element (for example, a semiconductor laser element), a light receiving element, an electronic device, or the like.

More specifically, in the case of a semiconductor light emitting device, if a voltage is applied between two positive and negative electrodes, a current is injected into the light emitting region, where recombination of carriers occurs and light is emitted. The structure is not particularly limited.

That is, the semiconductor light emitting device may be a light emitting diode or a semiconductor laser. When the semiconductor light emitting element is, for example, a semiconductor laser, the structure of the semiconductor laser is not particularly limited, and may be either an edge emitting type or a surface emitting type.

When the semiconductor device of the present invention is a semiconductor light emitting device, the semiconductor light emitting device may have an emission wavelength of 400 nm or less.

More specifically, in the present invention, p-type A containing B (boron) simultaneously with Mg (magnesium) is used.
In a semiconductor device having a semiconductor multilayer structure including l _x Ga _(1-x) N (0 ≦ x ≦ 1), B (B) and Mg (magnesium) are simultaneously added to a contact layer forming a p-side ohmic electrode.
(Boron) -added p-type Al _x Ga _(1-x) N (0
≦ x ≦ 1) can be used.

Note that such a semiconductor device is a p-type Al
_{As long} as a p-side ohmic electrode is formed on xGa _(1-x) N (0≤x≤1) and functions by injecting current, any element form can be adopted. That is, it can take the form of a semiconductor light emitting element (for example, a semiconductor laser element), a light receiving element, an electronic device, or the like.

More specifically, in the case of a semiconductor light emitting device, if a voltage is applied between two positive and negative electrodes, a current is injected into the light emitting region, where recombination of carriers occurs to emit light. The structure is not particularly limited.

That is, the semiconductor light emitting device may be a light emitting diode or a semiconductor laser. When the semiconductor light emitting element is, for example, a semiconductor laser, the structure of the semiconductor laser is not particularly limited, and may be either an edge emitting type or a surface emitting type.

Further, when the semiconductor device of the present invention is a semiconductor light emitting device, the semiconductor light emitting device may have an emission wavelength of 400 nm or less.

Further, p-type Al _x Ga.sub. _(1-x) N (0 ≦ x ≦
The contact layer using 1) (the contact layer forming the p-side ohmic electrode) does not need to be the outermost surface of the laminated structure, and may be, for example, the lowermost layer.

In the present invention, Mg (magnesium)
At the same time, p-type Al _x Ga to which B (boron) is added
_When a semiconductor device having a semiconductor laminated structure including _(1-x) N (0 ≦ x ≦ 1) is a semiconductor laser device, the semiconductor laser device is simultaneously treated with Mg (magnesium) and B (magnesium).
(Boron) -added p-type Al _x Ga _(1-x) N (0
≦ x ≦ 1) for at least one p−
It can have an n-junction.

Here, the structure of the semiconductor laser device is not particularly limited. That is, p-type Al to which B (boron) is added simultaneously with Mg (magnesium).
_{What is} claimed is _{: 1. A} group III nitride semiconductor laser device having at least one pn junction using xGa.sub. _(1-x) N (0.ltoreq.x.ltoreq.1) as a cladding layer, wherein carriers are injected into an active layer, and Any structure may be used as long as light can be extracted to the outside, and either an edge emitting type or a surface emitting type may be used.

In the present invention, Mg (magnesium)
At the same time, p-type Al _x Ga to which B (boron) is added
_{As a first} method for manufacturing a semiconductor device containing _(1-x) N (0 ≦ x ≦ 1), p-type Al _x Ga _(1-x) in which B (boron) is added simultaneously with Mg (magnesium _). N (0 ≦ x ≦
The semiconductor laminated structure including 1) is crystal-grown in a reaction system containing hydrogen gas, and cooling from the crystal growth temperature immediately after the crystal growth is performed in a cooling atmosphere containing a nitrogen source.
The above-described semiconductor device can be manufactured.

Here, the cooling atmosphere is nitrogen, or a mixed gas of an inert gas and a nitrogen raw material, or
A mixed gas containing several percent of hydrogen therein, a nitrogen source gas alone, or a mixed gas atmosphere of a nitrogen source gas and hydrogen can be used.

According to this first manufacturing method, Al _x Ga.sub. _(1-x) N having a high carrier concentration by simultaneously adding Mg and B is used.
By combining the crystal growth of (0 ≦ x ≦ 1) and the cooling in the above-described atmosphere gas containing the nitrogen source, the p of Al _x Ga _(1-x) N (0 ≦ x ≦ 1), which has been conventionally difficult, is obtained. Type crystal is a
Obtained by s-grown.

The reason why a p-type crystal can be obtained as-grown is that p-type Al _x G to which Mg and B are simultaneously added.
a _(1-x) N (0 ≦ x ≦ 1) is obtained by growing a material having a high carrier concentration, and performing cooling from the crystal growth temperature in the above-described cooling atmosphere. This is presumably because the diffusion into the crystal is suppressed, and the increase in resistance due to hydrogen passivation is prevented. Al _x Ga _(1-x) N
In the case where (0 ≦ x ≦ 1) is crystal-grown on the outermost surface of a single layer or a laminated structure, the nitrogen source contained in the cooling atmosphere further generates atomic nitrogen contributing to the formation reaction of AlGaN. Therefore, the dissociation of nitrogen from the surface of the AlGaN crystal is prevented, and as a result, the generation of nitrogen vacancies serving as donor defects is suppressed, the surface is prevented from increasing in resistance, and the low-resistance p-type Al _x Ga _(1-x) N (0 ≦ x ≦ 1) is a
It is thought to be obtained by s-grown.

When hydrogen is contained in the atmosphere gas during cooling, an unreacted organic raw material adsorbed on the crystal surface and a cleaning effect by hydrogen of the organic substance can be expected, so that the surface resistance due to surface contamination is reduced. Can be prevented from increasing.
This is an effect that cannot be obtained by the prior art.

The nitrogen source gas is not particularly limited. By using a compound such as NH ₃ which generates hydrogen by its decomposition, the effect of suppressing the decomposition of the crystal surface by the atomic nitrogen (the diffusion of hydrogen thereby) can be obtained. Suppression effect) and the cleaning effect by hydrogen are obtained at the same time.

According to the above-described prior art 1, in an atmosphere containing a compound that generates hydrogen or hydrogen gas, the resistance is increased.
Since it is difficult to make the p-type by discharging hydrogen from the group I nitride, the heat treatment was performed in an atmosphere containing no hydrogen. On the other hand, in the manufacturing method of the present invention, immediately after the crystal growth, Low resistance p-type Al _x Ga _(1-x) N (0 ≦ x ≦ 1)
By suppressing the diffusion and intrusion of hydrogen into the inside, it is possible to suppress the increase in resistance in the cooling process after crystal growth, and to reduce the p-type Al of low resistance.
and characterized by producing _{x Ga (1-x) N} (0 ≦ x ≦ 1), the prior art is different in principle. Further, the atmosphere differs from the prior art in that hydrogen may or may not contain hydrogen, and when hydrogen is contained, the effect of hydrogen is actively utilized.

That is, p-type Al _x Ga _(1-x) N to which B (boron) is added simultaneously with Mg (magnesium).
In a method for manufacturing a semiconductor device including (0 ≦ x ≦ 1),
NH ₃ (ammonia) can be used as the nitrogen source contained in the cooling atmosphere.

When NH ₃ is used as the nitrogen source gas, the effect of suppressing the decomposition of the crystal surface by the atomic nitrogen generated by its decomposition and the effect of cleaning by hydrogen are simultaneously obtained.

In the present invention, the p-type Al _x Ga _(1-x) N
As a second method for manufacturing a semiconductor device including (0 ≦ x ≦ 1), p-type Al _x Ga _(1-x) N (0 ≦ x ≦) in which B (boron) is added simultaneously with Mg (magnesium). Crystal growth is performed on the semiconductor laminated structure including 1) in a reaction system containing hydrogen gas, and cooling from the crystal growth temperature immediately after the crystal growth is performed by N
The above-described semiconductor device can be manufactured by performing the process in a cooling atmosphere of H ₃ .

In this second manufacturing method, since the atmosphere during cooling is only NH ₃ gas, the effect of suppressing the decomposition of the crystal surface by atomic nitrogen generated by the decomposition and the effect of cleaning by hydrogen are reduced. Can be more effectively obtained.

Conventionally, in a heat treatment in an NH ₃ atmosphere, the resistance of a p-type crystal is increased by hydrogen passivation,
Although a low-resistance p-type group III nitride was not obtained, in the present invention, the atmosphere was changed to NH ₃ during the cooling process after crystal growth.
By using gas, low-resistance p-type Al _x Ga _(1-x) N (0 ≦ x ≦ 1) in which surface deterioration is suppressed is as-grown.
n.

Hereinafter, the group III nitride semiconductor of the present invention, its manufacturing method, its semiconductor device and its manufacturing method will be described in more detail.

FIG. 1 is a diagram showing an example of a group III nitride semiconductor according to the present invention. Referring to FIG. 1, on a sapphire substrate 10, a low-temperature GaN buffer layer 11, a p-type Al _x Ga.sub. _(1-x) N (0 ≦ x ≦
1) The layers 12 are sequentially stacked.

Here, p-type Al _x Ga _(1-x) N (0 ≦ x ≦
1) The layer 12 is, for example, p-type Al _0.08 Ga with x = 0.08.
_0.92 N layer.

The p-type Al _0.08 Ga _0.92 N layer 12 contains B (boron) at the same time as p-type impurity Mg (magnesium). Here, both Mg and B are 8
About × 10 ¹⁹ cm ^{-3 is} contained.

The p-type Al _0.08 Ga _0.92 N layer 12 exhibited a low resistance p-type with a carrier concentration of 8 × 10 ¹⁷ cm ⁻³ . When B is not included, the carrier concentration is 1 × 10 ¹⁷ c
m ^-3 .

FIGS. 2 and 3 are views showing an example of the semiconductor device according to the present invention. The semiconductor device shown in FIGS.
An edge emitting light emitting diode and an edge receiving photodiode are monolithically integrated as a light receiving and emitting element. Note that FIG. 2 is a cross-sectional view of a light-emitting diode of the light-receiving / receiving element taken along a plane perpendicular to the light-emitting end face, and FIG. 3 is a cross-sectional view of a light-emitting diode taken along a plane parallel to the light-emitting end face.

Referring to FIGS. 2 and 3, the light emitting diode and the photodiode have a substantially rectangular parallelepiped shape, and are spatially separated so that one light emitting end face of the light emitting diode and the light receiving end face of the photodiode face each other. It has been formed.

The light emitting diode and the photodiode have the same laminated structure. The laminated structure has an AlN low-temperature buffer layer 21 on a sapphire substrate 20,
n-type Al _0.03 Ga _0.97 N contact layer 22, n-type Al
_0.07 Ga _0.93 N clad layer 23, In _0.17 Ga _0.83 N active layer 24, p-type Al _0.07 Ga _0.93 N clad layer 25, p
Type GaN contact layers 26 are sequentially laminated.

Here, the p-type Al _0.07 Ga _0.93 N cladding layer 25 and the p-type GaN contact layer 26 are doped with B (boron) simultaneously with Mg as a p-type dopant.

The light emitting diode and the photodiode are formed by stacking the above laminated structure on the surface of the p-type GaN contact layer
It is spatially separated by etching to the type Al _0.03 Ga _0.97 N contact layer 22. And n-type Al
The surface of the _0.03 Ga _0.97 N contact layer 22 is exposed, and on the exposed n-type Al _0.03 Ga _0.97 N contact layer 22,
An n-side ohmic electrode 29 made of Ti / Al is formed. Also, the light emitting diode and the photodiode p
A p-side ohmic electrode 28 made of Ni / Au is formed on the type GaN contact layer 26.

Further, in portions other than the ohmic electrode, S
An insulating protective film 27 made of iO ₂ is deposited. A wiring electrode 30 made of Ti / Al is formed on the insulating protective film 27. The wiring electrode 30 is electrically connected to the p-side ohmic electrode 28 of each of the light emitting diode and the photodiode. I have.

The side surfaces of the light emitting diode and the photodiode are formed substantially perpendicular to the substrate. The side faces of the light emitting diode and the photodiode that face each other via the groove become the light emitting end face 202 and the light receiving face 203, respectively. The end face of the light emitting diode opposite to the side face facing the photodiode is a light emitting end face 201 for emitting light to the outside.

This integrated type light receiving / emitting element operates by injecting a forward current into the light emitting diode and applying a reverse bias to the photodiode. That is, when a bias is applied in the forward or reverse direction to the p-side and n-side ohmic electrodes of each element, the light emitting diode emits light from the two light emitting end surfaces 201 and 202. And
Light emitted from the light emitting end face 202 facing the photodiode is incident on the light receiving surface 203 of the photodiode, and a photoelectromotive force corresponding to the intensity is generated in the photodiode, and is extracted to the outside as a photocurrent. By monitoring the photocurrent of the photodiode, the current injected into the light emitting diode can be adjusted to control the light output. When a current was injected into the light emitting diode to emit light, the peak wavelength of light emission was about 412 nm.

Next, a description will be given of an example of a manufacturing process of the integrated type light receiving / emitting element shown in FIGS. In this example of the manufacturing process, the stacked structure of the integrated type light receiving and emitting element was manufactured by crystal growth by MOCVD.

In this example of the manufacturing process, first, the sapphire substrate 20 was set in a reaction tube and heated at 1120 ° C. in a hydrogen gas to clean the surface of the substrate 20.

Next, the temperature was lowered to 520 ° C., the growth atmosphere was changed to a mixed gas atmosphere of NH ₃ , nitrogen and hydrogen, and TMA was
And a low-temperature AlN buffer 21 was deposited.

Next, the temperature was raised to 1070 ° C., TMG, TMA, and SiH ₄ were supplied according to the composition using hydrogen as a carrier gas, and the n-type Al _0.03 Ga _0.97 N contact layer 22 was formed to a thickness of 3 μm and the n-type Al _{A 0.07} Ga _0.93 N clad layer 23 was sequentially laminated to a thickness of 0.5 μm.

Next, the supply of hydrogen gas was stopped, the atmosphere was changed to a mixed gas atmosphere of NH ₃ and nitrogen, the temperature was lowered to 810 ° C., TMG and TMI were supplied using hydrogen as a carrier gas, and the In _0.17 Ga _0.83 N active layer was supplied. 24 was grown to a thickness of 50 nm.

Next, the atmosphere is changed to a mixed gas atmosphere of NH ₃ , nitrogen and hydrogen, the temperature is increased to 1070 ° C., and TMG, TMA, (EtCp) ₂ Mg
And B ₂ H ₆ are supplied in accordance with the composition, and p-type Al _0.07 G
a _0.93 N cladding layer 25 having a thickness of 0.5 μm and p-type Ga
N contact layers 26 were sequentially laminated to a thickness of 0.2 μm. After the completion of the crystal growth, a heat treatment was performed at 750 ° C. for 15 minutes in a nitrogen atmosphere to reduce the resistance of the p-type layer.

Next, a pattern in which two rectangular patterns each having a width of 30 μm and a length of 50 μm were arranged at a distance of 5 μm in the longitudinal direction and formed side by side was formed with a resist. Using this resist pattern as a mask, dry etching was performed to form a rectangular parallelepiped having a height of about 1.5 μm to become a light emitting diode and a photodiode, and to expose the n-type Al _0.03 Ga _0.97 N contact layer 22.

Next, SiO _{2 serving} as the insulating protective film 27 was deposited to a thickness of about 0.5 μm on the surface of the laminated structure.

Next, a p-side ohmic electrode 28 was formed. The step of forming the p-side ohmic electrode 28 is as follows. That is, first, after forming a nuclei stripe pattern with a resist on the light emitting diode and the photodiode, the insulating protective film 27 is etched to expose the p-type GaN contact layer 26.

Next, the p-side ohmic electrode material N
i / Au was deposited. Thereafter, the wafer was immersed in an organic solvent to dissolve the resist and lift off the electrode material deposited on the resist, thereby forming a p-side ohmic electrode pattern on the light emitting diode and the photodiode. Thereafter, a heat treatment was performed at 600 ° C. in a nitrogen atmosphere to form a p-side ohmic electrode 28 on the p-type GaN contact layer 26.

Next, an n-side ohmic electrode 29 and a wiring electrode 30 were formed. The steps of forming the n-side ohmic electrode 29 and the wiring electrode 30 are as follows. That is, first,
SiO on top of n-type Al _0.03 Ga _0.97 N contact layer 22
After forming a nuclei stripe pattern having a width of about 100 μm with a resist on the _second film 27, the SiO ₂ film 27 is etched to expose the n-type Al _0.03 Ga _0.97 N contact layer 22. Next, the resist is removed, and a lift-off pattern of the wiring electrode 30 and the n-side electrode 29 is formed again using the resist. Next, Ti / Al as an n-side ohmic electrode and a wiring electrode material was deposited. Thereafter, the wafer was immersed in an organic solvent to dissolve the resist and lift off the electrode material deposited on the resist, thereby forming an n-side ohmic electrode and a wiring electrode pattern. Thereafter, heat treatment was performed at 450 ° C. in a nitrogen atmosphere to form an n-side ohmic electrode 29. Next, dicing was performed to separate the integrated light emitting and receiving elements into chips.

FIG. 4 is a diagram showing another configuration example of the semiconductor device according to the present invention. In the example of FIG. 4, the semiconductor device is configured as a photodiode.

Referring to FIG. 4, this photodiode
Is a low-temperature GaN buffer layer on a sapphire substrate 40.
41, n-type GaN contact layer 42, low-temperature n-type Al_0.1
Ga_{0 .9}N buffer layer 43, n-type Al_0.08Ga_0.92N
Layer 44, p-type Al_0.08Ga_0.92N layer 45, AlN cap
Has a laminated structure in which the pump layers 46 are sequentially laminated.

Here, the p-type Al _0.08 Ga _0.92 N layer 45 is doped with B (boron) simultaneously with Mg as a p-type dopant.

Then, the above-mentioned laminated structure is etched until the n-type GaN contact layer 42 is exposed from the AlN cap layer 46 to form a mesa structure having a diameter of 150 μm.

The AlN cap layer 46 above the mesa structure is
The outer periphery is etched in a ring shape, and p-type Al_0.08G
a_0.92The surface of N layer 45 is exposed. Exposed p-type A
l_{0. 08}Ga_0.92On the surface of the N layer 45, a ring-shaped p-side
A mic electrode 48 is formed. Also exposed n-type
An n-side ohmic electrode 49 is provided on the GaN contact layer 42.
Is formed.

Further, ohmic electrodes 48 and 49 are formed.
In regions other than the portion where _TwoThe insulating protective film 47
Is formed. In addition, the mesa structure side and n-type GaN
SiO on tact layer 42_TwoOn the insulating protective film 47, the p-side
The wiring electrode 50 extended from the ohmic electrode 48 has a shape.
Has been established.

In the photodiode shown in FIG. 4, a portion surrounded by a ring-shaped p-side ohmic electrode 48 above the mesa structure becomes a light receiving surface 300. When a reverse bias is applied to the photodiode and the light receiving surface 300 is irradiated with light, a photocurrent corresponding to the light intensity flows. The photodiode of FIG. 4 functions as an optical sensor at a wavelength shorter than 346.1 nm.

Next, an example of a manufacturing process of the photodiode shown in FIG. 4 will be described. First, the sapphire substrate 40 was set in a reaction tube and heated in hydrogen gas at 1120 ° C. to clean the surface of the substrate 40.

Next, the temperature was lowered to 520 ° C., the atmosphere was changed to a mixed gas atmosphere of NH ₃ , nitrogen and hydrogen, TMG was flowed, and a low-temperature GaN buffer layer 41 was deposited.

Next, the temperature was raised to 1050 ° C.
And SiH ₄ to supply n-type GaN contact layer 42 to 2
μm thickness, then lower the temperature to 600 ° C.
Supplying TMG, TMA and SiH ₄ , low-temperature n-type Al _0.1
A Ga _0.9 N buffer layer 43 is deposited to a thickness of about 50 nm, then the temperature is increased to 1070 ° C. and TMG and TMA
And SiH ₄ to supply an n-type Al _0.08 Ga _0.92 N layer 44.
Was laminated to a thickness of 1 μm.

Next, the supply of SiH ₄ was stopped, and (EtC
p) ₂ Mg and B ₂ H ₆ are supplied, and p-type Al _0.08 Ga _0.92 N
The layer 45 was laminated to a thickness of 0.5 μm, and the AlN cap layer 46 was laminated to a thickness of 0.1 μm.

After completion of the crystal growth, a heat treatment was performed at 750 ° C. for 15 minutes in a nitrogen atmosphere to reduce the resistance of the p-type layer.

Next, a ring-shaped pattern having an inner diameter of 130 μm and an outer diameter of 145 μm was formed with a resist. Using this resist pattern as a mask, dry etching was performed to remove the AlN cap layer 46 by etching, exposing the surface of the p-type Al _0.08 Ga _0.92 N layer 45.

Next, a circular pattern having a diameter of 150 μm was formed with a resist on the ring pattern formed by dry etching. Using this resist pattern as a mask,
Dry etching was performed again to form a mesa shape having a height of about 2 μm, and the n-type GaN contact layer 42 was exposed.

After removing the resist mask, the wafer was set in a plasma CVD apparatus, and a SiO ₂ film 47 was formed on the surface.
Was deposited by about 0.5 μm.

Next, a p-side ohmic electrode 48 was formed. The step of forming the p-side ohmic electrode 48 is as follows. That is, first, after forming a ring-shaped nucleus pattern with a resist on the upper part of the mesa, the SiO ₂ film 47 is removed in a ring shape by wet etching, and p-type Al _0.08 Ga _0.92
The N layer 45 is exposed. Next, Ni / Au as a p-side ohmic electrode material was deposited. Thereafter, the wafer was immersed in an organic solvent to dissolve the resist and lift off the electrode material deposited on the resist to form a p-side ohmic electrode pattern on the mesa. Then, in a nitrogen atmosphere, 6
Heat treatment at 00 ° C. to form a p-type Al _0.08 Ga _0.92 N layer 45
A side ohmic electrode 48 was formed.

Next, an n-side ohmic electrode 49 and a wiring electrode 50 were formed. The steps of forming the n-side ohmic electrode 49 and the wiring electrode 50 are as follows. First, n-type GaN
After forming a nucleus pattern surrounding the mesa with a resist on the SiO ₂ film 47 on the contact layer 42,
_{2 The} film 47 is etched to form the n-type GaN contact layer 42.
To expose. Next, the resist is removed, and a lift-off pattern of the wiring electrode 50 and the n-side electrode 49 is formed using the resist again. Next, Ti / Al as an n-side ohmic electrode and a wiring electrode material was deposited. Thereafter, the wafer is immersed in an organic solvent, the resist is dissolved, and the electrode material deposited on the resist is lifted off.
And a pattern of the wiring electrode 50 were formed. Thereafter, a heat treatment is performed at 450 ° C. in a nitrogen atmosphere to form an n-side ohmic electrode 49.
Was formed.

FIG. 5 is a diagram showing another configuration example of the semiconductor device according to the present invention. In the example of FIG. 5, the semiconductor device is configured as a semiconductor laser. FIG. 5 is a sectional view taken on a plane perpendicular to the light emitting direction of the semiconductor laser.

Referring to FIG. 5, this semiconductor laser
Is an AlGaN low-temperature buffer on a sapphire substrate 60
Layer 61, n-type Al_0.03Ga_0.97N contact layer 62,
n-type Al_0.08Ga_0.92N cladding layer 63, n-type GaN
Id layer 64, In_0.15Ga_0.85N / In_0.02Ga_0.98N
Multiple quantum well active layer (2 pairs) 65, p-type Al_0.2Ga_0
.8N layer 66, p-type GaN guide layer 67, p-type Al_0.08G
a_0.92N cladding layer 68, p-type GaN contact layer 69
Are sequentially laminated.

Here, p-type Al_0.2Ga_0.8N layer 66, p
-Type GaN guide layer 67, p-type Al_{0. 08}Ga_0.92N crush
Layer 68 and p-type GaN contact layer 69
B (boron) is dopin at the same time as Mg as punt
Have been

Further, the above-mentioned laminated structure is etched from the surface of the p-type GaN contact layer 69 to the n-type Al _0.03 Ga _0.97 N contact layer 62 to form the n-type Al _0.03 Ga _0.97 N
The surface of the contact layer 62 is exposed. On the exposed n-type Al _0.03 Ga _0.97 N contact layer 62, Ti / A
An n-side ohmic electrode 72 of l is formed.

The current confinement ridge structure 400 is formed by etching from the surface of the p-type GaN contact layer 69 to the middle of the p-type Al _0.08 Ga _0.92 N cladding layer 68. The p-type Ga on the outermost surface of the ridge structure 400
On the N contact layer 69, a p-side ohmic electrode 71 made of Ni / Au is formed.

In addition, except for the electrode forming portion, the insulating protective film 70
Is deposited as SiO ₂ . Then, a wiring electrode 73 extending from the p-side electrode is formed on the insulating protective film 70.

An optical resonator end face is formed substantially perpendicular to the laminated structure and the current constriction ridge structure.

The semiconductor laser emits light when a current is injected into the electrodes 71 and 72 in the forward direction, and oscillates when the current is further increased. The oscillation wavelength is about 409 nm.

Next, an example of a manufacturing process of the semiconductor laser shown in FIG. 5 will be described. In this example of the manufacturing process, the crystal growth of the laminated structure of the semiconductor laser was performed by the MOCVD method.

In this manufacturing process example, first, the sapphire substrate 60 was set in a reaction tube, and heated at 1120 ° C. in a hydrogen gas to clean the surface of the substrate 60.

Next, the temperature was lowered to 520 ° C., the atmosphere was changed to a mixed gas atmosphere of NH ₃ , nitrogen and hydrogen, and TMG and T
MA was flowed to deposit a low-temperature AlGaN buffer layer 61.

Next, the temperature was raised to 1050 ° C., and TMG, TMI, and SiH ₄ were supplied according to the composition using hydrogen as a carrier gas, and the n-type Al _0.03 Ga _0.97 N contact layer 62 was formed to a thickness of 2 μm, _{The 0.08} Ga _0.92 N clad layer 63 was laminated to a thickness of 0.7 μm, and the n-type GaN guide layer 64 was laminated to a thickness of 0.1 μm.

Next, the supply of hydrogen gas was stopped, the atmosphere was changed to a mixed gas atmosphere of NH ₃ and nitrogen, the temperature was lowered to 810 ° C., TMG and TMI were supplied using hydrogen as a carrier gas, and In _0.15 Ga _0.85 N / In _{A 0.02} Ga _0.98 N multiple quantum well active layer 65 (two pairs) was grown.

Next, the growth atmosphere is a mixed gas atmosphere of NH ₃ , nitrogen and hydrogen, the temperature is increased to 1070 ° C., and TMG, TMA, (EtCp) _{2 is used} as a carrier gas with hydrogen.
Mg and B ₂ H ₆ are supplied according to the composition, and p-type Al _0.2 G
The a _0.8 N layer 66 has a thickness of 20 nm, the p-type GaN guide layer 67 has a thickness of 0.1 μm, the p-type Al _0.08 Ga _0.92 N cladding layer 68 has a thickness of 0.7 μm, and the p-type GaN contact layer 69 has a thickness of 0.7 μm. It was laminated to a thickness of 0.2 μm.

After completion of the crystal growth, a heat treatment was performed at 750 ° C. for 15 minutes in a nitrogen atmosphere to reduce the resistance of the p-type layer.

Next, a stripe pattern having a width of 4 μm was repeatedly formed with a resist at a pitch of 1 mm. Using this resist pattern as a mask, a depth of about 0.7 μm was dry-etched to form a ridge structure 400.

After removing the resist mask, a stripe pattern having a width of 500 μm and covering the ridge structure 400 was formed with a resist at a repetition pitch of 1 mm. Using this resist pattern as a mask, dry etching was performed to a depth of about 1.5 μm to expose the n-type Al _0.03 Ga _0.97 N contact layer 62. Next, about 0.5 μm of SiO _{2 serving} as the insulating protective film 70 was deposited on the surface of the laminated structure.

Next, a p-side ohmic electrode 71 was formed. The process for forming the p-side ohmic electrode 71 is as follows. That is, first, a nucleus stripe pattern is formed with a resist on the ridge structure 400, and then SiO ₂ is formed.
The film 70 is etched to expose the p-type GaN contact layer 69 on the ridge. Next, the resist is removed, and a Nuki stripe pattern having a width of about 450 μm is formed again with the resist, and N-type p-side ohmic electrode material is formed on the ridge.
i / Au was deposited. Thereafter, the wafer was immersed in an organic solvent, the resist was dissolved, and the electrode material deposited on the resist was lifted off to form a p-side ohmic electrode pattern only on the laminated structure of the semiconductor laser. Thereafter, heat treatment was performed at 600 ° C. in a nitrogen atmosphere to form a p-side ohmic electrode 71 on the p-type GaN contact layer 69.

Next, an n-side ohmic electrode 72 and a wiring electrode 73 were formed. The steps of forming the n-side ohmic electrode 72 and the wiring electrode 73 are as follows. That is, first,
n-type Al _0.03 Ga _0.97 N SiO on contact layer 62
_After a nuki stripe pattern having a width of about 100 μm is formed on the _second film 70 with a resist, the SiO ₂ film 70 is etched to expose the n-type Al _0.03 Ga _0.97 N contact layer 62. After removing the resist, the resist is applied again to form a lift-off electrode pattern on the p-side electrode and on the portion where the n-side ohmic electrode is to be formed. Next, an n-side ohmic electrode material and a wiring electrode material, Ti / Al, are deposited, the wafer is immersed in an organic solvent, the resist is dissolved, and the electrode material deposited on the resist is lifted off to form an n-side ohmic electrode pattern. And a wiring electrode pattern is formed. After that, heat treatment at 450 ° C. in a nitrogen atmosphere,
An n-side ohmic electrode 72 was formed.

Next, the sapphire substrate 60 is polished thinly and divided so as to be substantially perpendicular to the ridge structure 400 to form an optical resonator end face.

[0155] FIG. 6 is first prepared in the manufacturing method III nitride semiconductor (p-type Al _x Ga _(1-x described _above) N (0 ≦
It is a figure for explaining an example of x ≦ 1)). More specifically, FIG. 6 shows the p-type Al _x Ga.sub. _(1-x) N (0 ≦ x ≦
It is a figure for explaining the cooling process after the crystal growth of 1). In this example, p-type Al _x Ga _(1-x) N (0 ≦ x
≦ 1) is p-type Al _0.08 Ga _0.92 N, and the nitrogen source contained in the cooling atmosphere after the crystal growth is monomethylhydrazine (MMHy).

Referring to FIG. 6, first, a sapphire substrate 80 is set in a MOCVD apparatus,
By heating at 0 ° C., the surface of the substrate 80 was cleaned.

Next, the temperature was lowered to 520 ° C., the atmosphere was changed to a mixed gas atmosphere of NH ₃ , nitrogen and hydrogen, and TMG (trimethylgallium) was flown using hydrogen as a carrier gas to deposit a low-temperature GaN buffer layer 81.

Then, the temperature was raised to 1070 ° C., and TMG (trimethylgallium) and TMA (trimethylaluminum) were used as group III raw materials, (EtCp) ₂ Mg was used as a p-type dopant, and monomethylhydrazine (nitromethyl) was used as a nitrogen raw material. MMHy) and B ₂ H ₆ simultaneously with the mixed gas of nitrogen gas and hydrogen gas into the reaction tube, and p-type A
A l _0.08 Ga _0.92 N layer 82 was grown.

After the crystal growth, supply of the group III raw material, the p-type dopant raw material, and B ₂ H ₆ was stopped, and hydrogen gas (about 6 wt.
%), Nitrogen gas and monomethylhydrazine (MMHy) in a mixed gas atmosphere.

After cooling, the wafer was taken out, an electrode was formed on the surface of the crystal-grown Al _0.08 Ga _0.92 N crystal 82, and a hole measurement was performed. As a result, the carrier concentration of the Al _0.08 Ga _0.92 N layer 82 was 8 × 10 ¹⁷ cm ⁻³ , indicating a low-resistance p-type.

FIGS. 7 and 8 are views for explaining an example of a semiconductor device manufactured by the above-described first manufacturing method. Note that in the examples of FIGS. 7 and 8, in the first manufacturing method, the nitrogen source contained in the cooling atmosphere is NH ₃ . 7 and 8, the semiconductor device is a photodiode, FIG. 7 is a cross-sectional view of the photodiode, and FIG. 8 is a diagram for explaining a cooling process after crystal growth of a stacked structure to be a photodiode. It is.

Referring to FIG. 7 and FIG. 8, this photodiode has a low-temperature n-type Al _0.1
Ga _0.9 N buffer layer 91, n-type Al _0.08 Ga _0.92 N
A layer 92, a p-type Al _0.08 Ga _0.92 N layer 93, and an AlN cap layer 94 are sequentially laminated to form a laminated structure.

Here, the p-type Al _0.08 Ga _0.92 N layer 93 is doped with B (boron) simultaneously with Mg as a p-type dopant.

Referring to FIG. 7, the AlN cap layer 94 is left in a circular shape having a diameter of 150 μm, the periphery thereof is etched, and the surface of the p-type Al _0.08 Ga _0.92 N layer 93 is exposed. Exposed p-type Al _0.08 Ga _0.92 N layer 93
Is formed with a p-side ohmic electrode 95.
An n-side ohmic electrode 96 is formed on the back surface of the n-type GaN substrate 90.

In the photodiode shown in FIG. 7, the circular portion surrounded by the p-side ohmic electrode 95 becomes the light receiving surface 600. When a reverse bias is applied to the photodiode and light is irradiated on the light receiving surface 600, a photocurrent corresponding to the light intensity flows. The photodiode of FIG. 7 functions as an optical sensor at a wavelength shorter than 346.1 nm.

The photodiode shown in FIG.
Since the p-type Al _0.08 Ga _0.92 N layer 93 is formed by wn, no heat treatment for p-type conversion is required. As a result, since there is almost no decomposition of the crystal surface, a crystal defect does not occur and the photodiode has a small dark current.

Next, a method for manufacturing the photodiode shown in FIG. 7 will be described. First, an n-type GaN substrate 90 is set in a reaction tube, and an n-type GaN substrate 90 is mixed with hydrogen, nitrogen and ammonia gas.
The substrate 90 was heated to 20 ° C. to clean the surface of the substrate 90.

Next, the temperature was lowered to 600 ° C._ThreeWhen
In a mixed gas atmosphere of nitrogen and hydrogen, TMA and TMG and
SiH which is an n-type dopant gas_FourGas flow, low temperature n
Type Al_0.1Ga_0.9The N buffer layer 91 has a thickness of about 50 nm.
And then raise the temperature to 1070 ° C.
And TMA and SiH_FourTo supply n-type Al_0.08Ga_{0.9 Two}
The N layer 92 was laminated to a thickness of 1 μm.

Next, the supply of SiH ₄ was stopped, and (EtC
p) ₂ Mg and B ₂ H ₆ are supplied, and p-type Al _0.08 Ga _0.92 N
The layer 93 was laminated to a thickness of 0.5 μm, and the AlN cap layer 94 was laminated to a thickness of 0.1 μm.

Next, TMG, (EtCp) ₂ Mg, B ₂
The supply of H ₆ was stopped, the inside of the reaction tube was changed to a mixed gas atmosphere of nitrogen, ammonia, and hydrogen gas (6% of the whole), cooled to room temperature, and the substrate was taken out of the reaction tube.

Next, a circular pattern having a diameter of 150 μm was formed with a resist. Dry etching is performed using this resist pattern as a mask, and A other than the mask pattern is used.
The 1N cap layer 94 was removed by etching.

Next, a p-side ohmic electrode 95 was formed. The step of forming the p-side ohmic electrode 95 is as follows. That is, first, a circular pattern having a diameter of 140 μm is formed by a resist on the circular pattern of the AlN cap layer 94, and then Ni / Au which is a p-side ohmic electrode material is formed.
Was deposited. Thereafter, the substrate was immersed in an organic solvent to dissolve the resist, lift off the electrode material deposited on the resist, and remove the electrode material of the AlN cap layer 94. Thereafter, heat treatment is performed at 600 ° C. in a nitrogen atmosphere to form p-type Al.
_A p-side ohmic electrode 95 was formed on the _0.08 Ga _0.92 N layer 93.

Next, after the back surface of the substrate 90 was polished to a thickness of about 100 μm, Ti / Al as an n-side ohmic electrode material was deposited. Thereafter, 450 ° C. in a nitrogen atmosphere
To form an n-side ohmic electrode 96.

FIGS. 9 and 10 are views for explaining another example of the semiconductor device manufactured by the above-described first manufacturing method. 9 and 10, it is assumed that in the first manufacturing method, the nitrogen source contained in the cooling atmosphere is NH ₃ . 9 and 10, the semiconductor device is a photodiode, FIG. 9 is a cross-sectional view of the photodiode, and FIG. 10 is a diagram for explaining a cooling process after crystal growth of a stacked structure to be a photodiode. It is.

Referring to FIG. 9 and FIG. 10, this photodiode has a low-temperature n-type Al
_0.1 Ga _0.9 N buffer layer 101, n-type Al _0.08 Ga
_{A 0.92} N layer 102 and a p-type Al _0.08 Ga _0.92 N layer 103 are sequentially laminated to form a laminated structure.

Here, the p-type Al _0.08 Ga _0.92 N layer 103
Is doped with B (boron) simultaneously with Mg as a p-type dopant.

This photodiode is a p-type Al
It has a 150 μm diameter mesa structure formed by etching from the _0.08 Ga _0.92 N layer 103 until the n-type GaN substrate 100 is exposed.

Then, an SiO ₂ insulating film 104 is formed on the n-type GaN substrate 100 exposed by the mesa structure and the etching.

The SiO ₂ insulating film 104 on the upper part of the mesa structure
Is formed by etching the periphery of the p-type Al
The surface of the _0.08 Ga _0.92 N layer 103 is exposed. A ring-shaped p-side ohmic electrode 105 is formed on the exposed surface of the p-type Al _0.08 Ga _0.92 N layer 103. In addition, a wiring electrode 107 extending from the p-side ohmic electrode 105 is formed on the side surface of the mesa structure and on the SiO ₂ insulating protective film 104 on the n-type GaN substrate 100 exposed by the etching.

The n-type GaN substrate 100 has n
A side ohmic electrode 106 is formed.

In the photodiode shown in FIG. 9, the portion surrounded by the ring-shaped p-side ohmic electrode 105 above the mesa structure becomes the light receiving surface 500. When a reverse bias is applied to the photodiode and light is irradiated on the light receiving surface 500, a photocurrent corresponding to the light intensity flows. The photodiode in FIG. 9 functions as an optical sensor at a wavelength shorter than 346 nm.

The photodiode of FIG. 9 is an as-gro
Since the p-type Al _0.08 Ga _0.92 N layer 103 is made of wn, no heat treatment for p-type conversion is required. As a result, since there is almost no decomposition of the crystal surface, a crystal defect does not occur and the photodiode has a small dark current.

Next, a method for manufacturing the photodiode shown in FIG. 9 will be described. First, the n-type GaN substrate 100 is set in a reaction tube, and a mixed gas of hydrogen, nitrogen, and ammonia gas,
By heating to 120 ° C., the surface of the substrate 100 was cleaned.

Next, the temperature was lowered to 600 ° C._ThreeWhen
In a mixed gas atmosphere of nitrogen and hydrogen, TMA and TMG and
SiH which is an n-type dopant gas_FourGas flow, low temperature n
Type Al_0.1Ga_0.9The N buffer layer 101 has a thickness of about 50 nm.
Deposited to a thickness, then raise the temperature to 1070 ° C.
G, TMA and SiH_FourTo supply n-type Al_0.08Ga_0
.92The N layer 102 was laminated to a thickness of 1 μm.

Next, the supply of SiH ₄ was stopped, and (EtC
p) ₂ Mg and B ₂ H ₆ are supplied, and p-type Al _0.08 Ga _0.92 N
Layer 103 was laminated to a thickness of 0.5 μm.

Subsequently, TMG, (EtCp) ₂ Mg, B ₂
The supply of H ₆ was stopped, the inside of the reaction tube was changed to a mixed gas atmosphere of nitrogen, ammonia, and hydrogen gas (6% of the whole), cooled to room temperature, and the substrate was taken out of the reaction tube.

Next, a circular pattern having a diameter of 150 μm was formed with the resist. Using this resist pattern as a mask, dry etching was performed to form a mesa shape having a height of about 2 μm, and the n-type GaN substrate 100 was exposed.

After removing the resist mask, the wafer was set in a plasma CVD apparatus, and a SiO ₂ film 10 was formed on the surface.
4 was deposited to a thickness of about 0.5 μm.

Next, a p-side ohmic electrode 105 was formed. The process for forming the p-side ohmic electrode 105 is as follows. That is, first, a ring-shaped nucleus pattern is formed on the mesa with a resist, and then the SiO ₂ film 104 is removed by a ring etching by wet etching to form p-type Al _0.08 G
a _0.92 N layer 103 is exposed. Next, Ni / Au as a p-side ohmic electrode material was deposited. Thereafter, the wafer was immersed in an organic solvent to dissolve the resist and lift off the electrode material deposited on the resist to form a p-side ohmic electrode pattern on the mesa. Thereafter, heat treatment was performed at 600 ° C. in a nitrogen atmosphere to form a p-side ohmic electrode 105 on the p-type Al _0.08 Ga _0.92 N layer 103.

Next, the wiring electrode 107 was formed. The process of forming the wiring electrode 107 is as follows. That is, first, a lift-off pattern of the wiring electrode 107 is formed using a resist. Next, Ti / Al as a wiring electrode material was deposited. Thereafter, the wafer was immersed in an organic solvent, the resist was dissolved, and the electrode material deposited on the resist was lifted off to form the wiring electrode 107.

Next, an n-type electrode 106 was formed on the back surface of the substrate 100. That is, Ti / A
Then, heat treatment was performed at 450 ° C. in a nitrogen atmosphere to form an n-side ohmic electrode 106.

Lastly, dicing was performed to separate the photodiodes into chips.

FIGS. 11 and 12 are views for explaining an example of a semiconductor device manufactured by the above-described second manufacturing method. In the examples of FIGS. 11 and 12, the semiconductor device is an edge emitting light emitting diode. FIG. 11 is a cross-sectional view of the edge emitting light emitting diode taken along a plane perpendicular to the light emitting end face.
FIG. 12 is a diagram for explaining a cooling process after crystal growth of a stacked structure that becomes an edge-emitting light emitting diode.

Referring to FIGS. 11 and 12, the light emitting diode has a substantially rectangular parallelepiped shape, and one side surface of the light emitting diode is a light emitting end surface.

Further, the laminated structure of the light emitting diode has an n-type
On a GaN substrate 110, n-type Al_{0. 07}Ga_0.93N low temperature bath
Buffer layer 111, n-type Al_0.2Ga_0.8N clad layer 1
12, Al_0.07Ga_0.93N active layer 113, p-type Al_0.2
Ga_0.8N cladding layer 114, p-type GaN contact layer
115 are sequentially laminated.

Here, B is added to the p-type Al _0.2 Ga _0.8 N cladding layer 114 and the p-type GaN contact layer 115 simultaneously with Mg which is a p-type impurity.

A p-side ohmic electrode 116 made of Ni / Au is formed on the p-type GaN contact layer 115 of the light emitting diode.

On the back surface of the substrate 110, Ti / Al
An n-side ohmic electrode 117 is formed.

The side surface of the light emitting diode is formed perpendicular to the substrate 110.

In this light emitting diode, when a forward bias is applied to the p-side and n-side ohmic electrodes 116 and 117, light is emitted to the outside from a light emitting end face 700 which is one side surface of the light emitting diode. The peak wavelength of light emission of this light emitting diode was about 350 nm.

Next, a method for manufacturing the light emitting diode of FIG. 11 will be described. The stacked structure of the light emitting diode is MOC
It was produced by crystal growth by the VD method. First, the n-type GaN substrate 110 is set in a reaction tube, and the
By heating at 0 ° C., the surface of the substrate 110 was cleaned.

Next, the temperature was lowered to 600 ° C., the atmosphere was changed to a mixed gas atmosphere of NH ₃ , nitrogen and hydrogen, and TMA and T
An n-type low-temperature Al _0.07 Ga _0.93 N buffer layer 111 was deposited by flowing MG and SiH ₄ gas as an n-type dopant gas.

Next, the temperature was raised to 1070 ° C. and TM
G, TMA and SiH ₄ as an n-type impurity gas are supplied according to the composition, and the n-type Al _0.2 Ga _0.8 N clad layer 1 is supplied.
12 is a 0.3 μm-thick Al _0.07 Ga _0.93 N active layer 1
13 was laminated to a thickness of 0.05 μm.

[0204] Then, instead of n-type impurity material is a p-type impurity material (EtCp) ₂ Mg and at the same time B ₂
H ₆ was supplied according to the composition, and the p-type Al _0.2 Ga _0.8 N cladding layer 114 was laminated to a thickness of 0.3 μm, and the p-type GaN contact layer 115 was laminated to a thickness of 0.2 μm.

After completion of the crystal growth, the reaction tube was cooled from the growth temperature to room temperature in an atmosphere containing only ammonia gas.

After cooling, if a tester is applied to the surface of the laminated structure, there is conduction and the p-type GaN contact layer 115 on the surface is provided.
Was confirmed to have low resistance.

Next, the p-side ohmic electrode material N
i / Au was deposited on the upper surface of the laminated structure. Thereafter, heat treatment is performed at 600 ° C. in a nitrogen atmosphere to form a p-type GaN contact layer 1.
The p-side ohmic electrode 116 was formed on No. 15.

Next, the back surface of the GaN substrate 110 was polished to a thickness of about 100 μm. And the GaN substrate 1
Ti / Al which is an n-side ohmic electrode material
And heat-treated at 450 ° C. in a nitrogen atmosphere to form an n-side ohmic electrode 117.

Next, the substrate is cleaved and the exit end face 70 is cut.
0 and chip separation were performed.

FIGS. 13, 14 and 15 are views for explaining another example of the semiconductor device manufactured by the above-described second manufacturing method. 13, 14, and 15, the semiconductor device is a semiconductor laser. FIG. 13 is a perspective view of the semiconductor laser, and FIG. 14 is a cross-sectional view taken along a plane perpendicular to the light emission direction of the semiconductor laser. FIG. 15 is a view for explaining a cooling process after the crystal growth of the laminated structure to be a semiconductor laser.

Referring to FIGS. 13 to 15, a laminated structure 1000 of a semiconductor laser comprises an n-type AlGaN low-temperature buffer layer 121, an n-type Al
_0.03 Ga _0.97 N high temperature buffer layer 122, n-type Al _0.07
Ga _0.93 N clad layer 123, n-type GaN guide layer 12
4, In _0.15 Ga _0.85 N / In _0.02 Ga _0.98 N multiple quantum well active layer 125, p-type Al _0.2 Ga _0.8 N layer 126, p
A GaN guide layer 127, a p-type Al _0.07 Ga _0.93 N cladding layer 128, and a p-type GaN contact layer 129 are sequentially laminated.

Then, a p-type Al _0.2 Ga _0.8 N layer 126,
The p-type GaN guide layer 127, the p-type Al _0.07 Ga _0.93 N cladding layer 128, and the p-type GaN contact layer 129 include:
B is doped simultaneously with Mg which is a p-type impurity.

The laminated structure 1000 is etched from the surface of the p-type GaN contact layer 129 to the middle of the p-type Al _0.07 Ga _0.93 N clad layer 128 to form the current confinement ridge structure 800.

On the outermost p-type GaN contact layer 129 of the ridge structure 800, a p-side ohmic electrode 131 made of Ni / Au is formed. Also, p
Except for the side electrode forming portion, SiO 2 is used as the insulating protection film 130.
₂ have been deposited.

The optical resonator end faces 801 and 802 are substantially perpendicular to the laminated structure 1000 and the current constriction ridge structure 800.
Are formed.

On the back surface of the GaN substrate 120, Ti
An n-side ohmic electrode 132 made of / Al is formed.

The electrodes 131 and 132 of this semiconductor laser
When a current was injected in the forward direction, light was emitted, and when the current was further increased, laser oscillation occurred. The oscillation wavelength was about 409 nm.

Next, a method of manufacturing the semiconductor laser shown in FIGS. 13 and 14 will be described. The crystal growth of the laminated structure 1000 of the semiconductor laser was performed by the MOCVD method. First, n
The type GaN substrate 120 was set in a reaction tube, and heated to 1120 ° C. in a mixed gas of hydrogen, nitrogen and ammonia gas to clean the surface of the substrate 120.

Next, the temperature was lowered to 600 ° C., and in a mixed gas atmosphere of NH ₃ , nitrogen and hydrogen, TMA, TMG and SiH ₄ gas as an n-type dopant gas were flowed to deposit an n-type low-temperature AlGaN buffer layer 121. .

Next, the temperature was raised to 1070 ° C. and hydrogen was removed.
TMG, TMA, n-type impurity gas as carrier gas
And SiH_FourIs supplied according to the composition, and n-type Al_0.03G
a_{0.9 7}N high temperature buffer layer 122 is 1 μm thick, n-type
Al_0.07Ga_0.93The thickness of the N cladding layer 123 is 0.5 μm.
Now, the n-type GaN guide layer 124 is formed to a thickness of 0.1 μm.
Layered.

Next, the supply of hydrogen gas was stopped, the atmosphere was changed to a mixed gas atmosphere of NH ₃ and nitrogen, the temperature was lowered to 810 ° C., TMG and TMI were supplied using hydrogen as a carrier gas, and In _0.15 Ga _0.85 N / In _{A 0.02} Ga _0.98 N multiple quantum well active layer 125 (two pairs) was grown.

Then, the growth atmosphere is a mixed gas atmosphere of NH ₃ , nitrogen and hydrogen, the temperature is raised to 1070 ° C., and TMG, TMA and (EtCp) ₂ Mg, B ₂ H ₆ is supplied according to the composition, and the p-type Al _0.2 Ga _0.8 N layer 126 is formed to a thickness of 20 nm,
The p-type GaN guide layer 127 has a thickness of 0.1 μm,
The l _0.07 Ga _0.93 N cladding layer 128 was laminated to a thickness of 0.5 μm, and the p-type GaN contact layer 129 was laminated to a thickness of 0.2 μm.

After completion of the crystal growth, the inside of the reaction tube was set to an atmosphere containing only ammonia gas, and cooled from the growth temperature to room temperature.

After cooling, applying a tester to the surface of the laminated structure provides conduction and the p-type GaN contact layer 129 on the surface.
Was confirmed to have low resistance.

Next, a stripe pattern having a width of 4 μm was repeatedly formed with a resist at a pitch of 300 μm, and a depth of about 0.7 μm was dry-etched using the resist pattern as a mask to form a ridge structure 800.

Thereafter, the resist mask is removed, and the
Later, SiO which becomes the insulating protective film 130 _TwoThe laminated structure of the surface
Was deposited to a thickness of about 0.5 μm.

Next, a p-side ohmic electrode 131 was formed. The process for forming the p-side ohmic electrode 131 is as follows. That is, first, on the upper part of the ridge structure 800,
After forming a nuclei stripe pattern with resist,
The O ₂ insulating protective film 130 is etched to expose the p-type GaN contact layer 129 on the ridge 800. Next, the resist was removed, and Ni / Au as a p-side ohmic electrode material was deposited on the surface of the wafer. Thereafter, heat treatment was performed at 600 ° C. in a nitrogen atmosphere to form a p-side ohmic electrode 131 on the p-type GaN contact layer 129.

Next, after the back surface of the substrate 120 was polished to a thickness of about 100 μm, Ti / Al as an n-side ohmic electrode material was deposited on the back surface of the substrate 120. afterwards,
Heat treatment was performed at 450 ° C. in a nitrogen atmosphere to form an n-side ohmic electrode 132.

Next, the wafer on which the semiconductor laser structure was formed was cleaved so as to be substantially perpendicular to the ridge 800, and optical resonator end faces 801 and 802 were formed.

FIGS. 16, 17 and 18 are views for explaining an example of a semiconductor light emitting device manufactured by the above-described second manufacturing method. 16, 17, and 18
In the example shown in FIG. 1, the semiconductor light emitting device is a semiconductor laser, and FIG.
6 is a perspective view of the semiconductor laser, FIG. 17 is a cross-sectional view taken along a plane perpendicular to the light emitting direction of the semiconductor laser, and FIG. 18 is a view for explaining a cooling process after crystal growth of a laminated structure that becomes the semiconductor laser. .

Referring to FIG. 16 to FIG. 18, the stacked structure 2000 of the semiconductor laser includes an n-type AlGaN low-temperature buffer layer 141 and an n-type Al
_0.03 Ga _0.97 N high temperature buffer layer 142, n-type Al _0.15
Ga _0.85 N cladding layer 143, n-type Al _0.1 Ga _0.9 N guide layer 144, GaN / Al _0.1 Ga _0.9 N multiple quantum well active layer 145, p-type Al _0.2 Ga _0.8 N layer 146, p-type A
l _0.1 Ga _0.9 N guide layer 147, p-type Al _0.15 Ga _0.85
The N cladding layer 148 and the p-type GaN contact layer 149 are sequentially laminated.

Then, a p-type Al _0.2 Ga _0.8 N layer 146,
p-type Al _0.1 Ga _0.9 N guide layer 147, p-type Al _0.15 G
a _0.85 N cladding layer 148, p-type GaN contact layer 1
49 is doped with B simultaneously with Mg which is a p-type impurity.

The layered structure 2000 is etched from the surface of the p-type GaN contact layer 149 to the middle of the p-type Al _0.15 Ga _0.85 N clad layer 148 to form the current confinement ridge structure 900.

Then, on the p-type GaN contact layer 149 on the outermost surface of the ridge structure 900, a p-side ohmic electrode 151 made of Ni / Au is formed. Also, p
Except for the side electrode forming portion, SiO 2 is used as the insulating protective film 150.
₂ have been deposited.

Then, the optical resonator end faces 901 and 902 are substantially perpendicular to the laminated structure 2000 and the current confinement ridge structure 900.
Are formed.

On the back surface of the GaN substrate 140, Ti
An n-side ohmic electrode 152 made of / Al is formed.

The electrodes 151 and 152 of this semiconductor laser
When a current was injected in the forward direction, light was emitted, and when the current was further increased, laser oscillation occurred. The oscillation wavelength was about 365 nm.

Next, a method of manufacturing the semiconductor laser shown in FIGS. 16 and 17 will be described. The crystal growth of the laminated structure 2000 of the semiconductor laser was performed by the MOCVD method. First, n
The GaN substrate 140 was set in a reaction tube and heated to 1120 ° C. in a mixed gas of hydrogen, nitrogen and ammonia gas to clean the surface of the substrate 140.

Then, the temperature was lowered to 600 ° C., and in a mixed gas atmosphere of NH ₃ , nitrogen and hydrogen, TMA, TMG and SiH ₄ gas as an n-type dopant gas were flown to deposit an n-type low-temperature AlGaN buffer layer 141. .

Next, the temperature was raised to 1070 ° C. and hydrogen was removed.
TMG, TMA, n-type impurity gas as carrier gas
And SiH_FourIs supplied according to the composition, and n-type Al_0.03G
a_{0.9 7}N high temperature buffer layer 142 is 1 μm thick, n-type
Al_0.15Ga_0.85The thickness of the N cladding layer 143 is 0.5 μm.
Now, n-type Al_0.1Ga_0.90.1 μm for the N guide layer 144
GaN / Al_0.1Ga_0.9
N multiple quantum well active layers 145 (three pairs) were stacked.

Next, TMG, TMA, p-type impurity raw materials (EtCp) ₂ Mg and B ₂ H ₆ are supplied according to the composition, and the p-type Al _0.2 Ga _0.8 N layer 146 is formed to a thickness of 20 nm.
The p-type Al _0.1 Ga _0.9 N guide layer 147 has a thickness of 0.1 μm and the p-type Al _0.15 Ga _0.85 N cladding layer 148 has a thickness of 0.5 μm.
μm thickness, 0.2 μm p-type GaN contact layer 149
m in order.

After completion of the crystal growth, the reaction tube was cooled from the growth temperature to room temperature by setting the atmosphere in the reaction tube to only ammonia gas.

After cooling, if a tester is applied to the surface of the laminated structure, there is conduction and the p-type GaN contact layer 149 on the surface is provided.
Was confirmed to have low resistance.

Next, a stripe pattern having a width of 4 μm was repeatedly formed with a resist at a pitch of 300 μm, and a depth of about 0.7 μm was dry-etched using the resist pattern as a mask to form a ridge structure 900.

Thereafter, the resist mask is removed, and the
Later, SiO which becomes the insulating protective film 150 _TwoThe laminated structure of the surface
Was deposited to a thickness of about 0.5 μm.

Next, a p-side ohmic electrode 151 was formed. The step of forming the p-side ohmic electrode 151 is as follows. That is, first, on the upper part of the ridge structure 900,
After forming a nuclei stripe pattern with resist,
The p-type GaN contact layer 149 on the ridge 900 is exposed by etching the O ₂ insulating protective film 150. Next, the resist was removed, and Ni / Au as a p-side ohmic electrode material was deposited on the surface of the wafer. Thereafter, heat treatment was performed at 600 ° C. in a nitrogen atmosphere to form a p-side ohmic electrode 151 on the p-type GaN contact layer 149.

Next, after the back surface of the substrate 140 was polished to a thickness of about 100 μm, Ti / Al as an n-side ohmic electrode material was deposited on the back surface of the substrate 140. afterwards,
Heat treatment was performed at 450 ° C. in a nitrogen atmosphere to form an n-side ohmic electrode 152.

Next, the wafer on which the semiconductor laser structure was formed was cleaved so as to be substantially perpendicular to the ridge 900, and optical resonator end faces 901 and 902 were formed.

[0249]

As described above, according to the first aspect of the present invention, p-type Al _x Ga.sub. _(1-x) N to which Mg is added.
(0 ≦ x ≦ 1), the p-type Al _x Ga _(1-x) N
In (0 ≦ x ≦ 1), B is added simultaneously with Mg, so that the instability of the crystal due to the addition of Mg is reduced, and the carrier concentration is reduced even if Mg is added at a high concentration. Not
As a result, p-type Al _x G with a higher carrier concentration than ever before
a _(1-x) N (0 ≦ x ≦ 1) can be obtained.

According to the second aspect of the present invention, since the semiconductor device has the semiconductor multilayer structure including the group III nitride semiconductor according to the first aspect, the semiconductor device having the conventional group III nitride semiconductor multilayer structure can be used. P-type A that caused the increase in resistance
Since the carrier concentration of l _x Ga _(1-x) N (0 ≦ x ≦ 1) is high and the resistance is low, the operating voltage is low, heat is hardly generated, and the characteristics of the semiconductor device are improved and the reliability is improved. Can be.

In particular, when the semiconductor device is a light receiving element,
Low resistance wide gap p-type Al _xGa_(1-x)N (0 ≦
x ≦ 1) can be used, so the wavelength range is shorter than before.
(Ultraviolet region). Also semiconductor
When the device is a light-emitting device, the wavelength is shorter than
The light emitting element emits light.

According to the third aspect of the present invention, in the semiconductor device according to the second aspect, the group III nitride semiconductor according to the first aspect is used for the contact layer for forming the p-side ohmic electrode. The contact resistance of the p-side ohmic electrode, which has caused the increase in the resistance of the semiconductor device having the group III nitride semiconductor laminated structure, is reduced, the operating voltage is low, and the electrode is hardly damaged by heat generation. And improve reliability.

According to a fourth aspect of the present invention, in the semiconductor device according to the second or third aspect, the semiconductor device is a semiconductor light emitting element and has a high carrier concentration.
Type AlGaN is used for semiconductor light emitting devices,
The element resistance is lower than that of the conventional one, so that even when a high output operation is performed, heat generation is small and deterioration of the element is small.
In addition, since p-type AlGaN shows p-type characteristics as-grown, time and cost for special processing for p-type conversion are not required. Therefore, it is possible to provide a low-cost semiconductor light-emitting device having a lower operating voltage, higher output, longer life, higher reliability, and lower reliability than conventional ones.

According to a fifth aspect of the present invention, in the semiconductor device according to the fourth aspect, the semiconductor light emitting element is a semiconductor laser element, and a p-type A with a high carrier concentration.
Since 1GaN is used for the semiconductor laser, the device resistance is lower than that of the conventional device, and therefore, even when high output operation is performed, heat generation is small, and deterioration of the device can be reduced.

In the conventional group III nitride semiconductor laser, since the carrier concentration of the p-type AlGaN cladding layer is low, electrons overflow from the active layer to the p-type cladding layer, resulting in a decrease in luminous efficiency. The semiconductor laser of the present invention can use a p-type AlGaN layer having a high carrier concentration for the cladding layer, and thus has high luminous efficiency.

Further, p-type AlGaN is as-grown.
Since n indicates a p-type characteristic, no special processing time and cost for p-type conversion is required. Therefore, it is possible to provide a low-cost semiconductor laser having a lower operating voltage, higher output, longer life, higher reliability and higher reliability than the conventional one.

According to the sixth aspect of the present invention, in the semiconductor device according to the fourth or fifth aspect, the semiconductor light emitting element has an emission wavelength of 400 nm or less;
Al composition ratio in the AlGaN cladding layer is large,
Since p-type AlGaN having a high carrier concentration can be used, high-efficiency light emission in a wavelength region of 400 nm or less, which has been conventionally difficult, can be realized.

According to a seventh aspect of the present invention, in the semiconductor device according to the fifth aspect, the semiconductor laser element as the semiconductor device is formed by using at least a group III nitride semiconductor according to the first aspect in a cladding layer. P-type Al _x Ga.sub. _(1-x) N (0.ltoreq.x ₎ having one pn junction and having a higher carrier concentration than the conventional group III nitride semiconductor laser device.
Since <1) is used for the p-type cladding layer, a semiconductor laser device having a low operating voltage, a high output, a long life and a high reliability can be provided. Further, since it is not necessary to manufacture a superlattice structure, the time required for crystal growth and the apparatus cost can be reduced, and a low-cost semiconductor laser device can be provided.

According to the eighth aspect of the present invention, Mg
At the same time, p-type Al _x Ga _(1-x) N (0
≤ x ≤ 1), a crystal is grown in a reaction system containing hydrogen gas, and cooling from the crystal growth temperature immediately after the crystal growth is performed in a cooling atmosphere containing a nitrogen raw material. Al _x Ga _(1-x) N with high carrier concentration
By combining the crystal growth of (0 ≦ x ≦ 1) and cooling in an atmosphere gas containing a nitrogen source, it is difficult to form Al _x Ga _(1-x) N (0 ≦ x ≦ 1), which has been conventionally difficult. A p-type crystal in a grown state is obtained.

According to the ninth aspect of the present invention, in the method of manufacturing a group III nitride semiconductor according to the eighth aspect, the nitrogen source contained in the cooling atmosphere is NH _3. In addition to the effect, the hydrogen generated by the decomposition of NH ₃ can be expected to have a cleaning effect due to the unreacted organic raw material adsorbed on the crystal surface and the hydrogen of the organic substance, thereby preventing an increase in surface resistance due to surface contamination. it can.

According to the tenth aspect of the present invention, M
p-type Al _x Ga _(1-x) N to which B is added at the same time as
(0 ≦ x ≦ 1) is grown in a reaction system containing hydrogen gas, and cooling from the crystal growth temperature immediately after the crystal growth is performed by N
Since the cooling is performed in a cooling atmosphere of H ₃ , and the cooling atmosphere is NH ₃ gas, the effect of suppressing the decomposition of the crystal surface by the atomic nitrogen generated by the decomposition and the cleaning effect by the hydrogen can be reduced. As a result, p-type Al _x Ga.sub. _(1-x) N (0.ltoreq.x.ltoreq.1 ₎ having a higher carrier concentration than before can be obtained.
-Grown.

Further, according to the eleventh aspect of the present invention, M
p-type Al _x Ga _(1-x) N to which B is added at the same time as
The semiconductor multilayer structure including (0 ≦ x ≦ 1) is crystal-grown in a reaction system containing hydrogen gas, and cooling from the crystal growth temperature immediately after the crystal growth is performed in an atmosphere containing a nitrogen source. , Mg and B are simultaneously added, and crystal growth of Al _x Ga.sub. _(1-x) N (0.ltoreq.x.ltoreq.1 ₎ with high carrier concentration is combined with cooling in an atmosphere gas containing a nitrogen source. As a result, a p-type crystal of Al _x Ga _(1-x) N (0 ≦ x ≦ 1), which has been difficult in the past, can be obtained as-grown.

Al _x Ga _(1-x) N (0 ≦ x ≦ 1) is a single layer,
Alternatively, when the crystal is grown on the outermost surface of the laminated structure, the nitrogen source contained in the cooling atmosphere generates atomic nitrogen that contributes to the formation reaction of AlGaN.
Dissociation of nitrogen from the GaN crystal surface is prevented, and as a result, generation of nitrogen vacancies serving as donor defects is suppressed, and the surface is prevented from increasing in resistance.

The suppression of decomposition by the nitrogen raw material is controlled by p-type AlG
Since it is effective not only for aN but also for other group III nitride crystals, deterioration of the outermost surface of the group III nitride laminated structure constituting the semiconductor device due to thermal decomposition is prevented, and a crystal having good crystal quality can be used for the semiconductor device. Can be used for Accordingly, a highly reliable semiconductor device having excellent electric characteristics as compared with the related art can be manufactured.

Further, since heat treatment for p-type conversion is not required, the manufacturing process of the semiconductor device can be simplified, and equipment cost and energy consumption for heat treatment can be reduced. Can be.

According to the twelfth aspect of the present invention, in the method of fabricating a semiconductor device according to the eleventh aspect, the nitrogen source contained in the cooling atmosphere is NH _3. Thus, the cleaning effect of the unreacted organic raw material adsorbed on the crystal surface or the organic hydrogen can be expected by the hydrogen generated by the decomposition of NH ₃ , and an increase in surface resistance due to surface contamination can be prevented.

Therefore, the carrier concentration of p
Type Al _x Ga _(1-x) N (0 ≦ x ≦ 1) as-grown
In addition to being able to be manufactured, the electrical characteristics are better than before,
A highly reliable semiconductor device can be manufactured at low cost.

Further, according to the thirteenth aspect, M
p-type Al _x Ga _(1-x) N to which B is added at the same time as
The semiconductor laminated structure including (0 ≦ x ≦ 1) is crystal-grown in a reaction system containing hydrogen gas, and cooling from the crystal growth temperature immediately after the crystal growth is performed in a cooling atmosphere of NH _3. Since the cooling atmosphere is NH ₃ gas, the effect of suppressing the decomposition of the crystal surface by the atomic nitrogen generated by the decomposition and the cleaning effect by hydrogen can be obtained more effectively than in the case of the mixed gas atmosphere. result,
P-type Al _x Ga _(1-x) N with higher carrier concentration than before
(0 ≦ x ≦ 1) can be produced as-grown. Thus, a highly reliable semiconductor device which has better electric characteristics than a conventional semiconductor device can be manufactured at low cost.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a group III nitride semiconductor according to the present invention.

FIG. 2 is a diagram illustrating an example of a semiconductor device according to the present invention.

FIG. 3 is a diagram illustrating an example of a semiconductor device according to the present invention.

FIG. 4 is a diagram showing another configuration example of the semiconductor device according to the present invention.

FIG. 5 is a diagram showing another configuration example of the semiconductor device according to the present invention.

FIG. 6 shows a p-type Al _x Ga.sub. _(1-x) N (0 ≦ x ≦ 1) of the present invention.
FIG. 5 is a diagram for explaining a cooling process after crystal growth of FIG.

FIG. 7 illustrates an example of a photodiode.

8 is a diagram for explaining a cooling process after crystal growth of a stacked structure that becomes the photodiode of FIG. 7;

FIG. 9 illustrates an example of a photodiode.

FIG. 10 is a diagram for explaining a cooling process after crystal growth of a stacked structure that becomes the photodiode of FIG. 9;

FIG. 11 is a diagram illustrating an example of an edge-emitting light emitting diode.

FIG. 12 is a diagram for explaining a cooling process after crystal growth of a stacked structure that becomes the edge emitting light emitting diode of FIG. 11;

FIG. 13 is a perspective view showing an example of a semiconductor laser.

14 is a cross-sectional view taken along a plane perpendicular to the light emission direction of the semiconductor laser in FIG.

FIG. 15 is a view for explaining a cooling process after crystal growth of a laminated structure which becomes the semiconductor laser of FIGS. 13 and 14;

FIG. 16 is a perspective view showing an example of a semiconductor laser.

17 is a cross-sectional view taken along a plane perpendicular to the light emission direction of the semiconductor laser in FIG.

FIG. 18 is a diagram for explaining a cooling process after crystal growth of the laminated structure that becomes the semiconductor laser of FIGS. 16 and 17;

FIG. 19 is a view showing a conventional semiconductor laser.

[Explanation of symbols]

10, 20, 40, 60, 80 Sapphire substrate 11, 41, 81 Low-temperature GaN buffer layer 12, 82 p-type Al _0.08 Ga _0.92 N layer 21, low-temperature AlN buffer layer 22, 62 n-type Al _0.03 Ga _0.97 N contact layer 23 , 123 n-type Al _0.07 Ga _0.93 N cladding layer 24 In _0.17 Ga _0.83 N active layer 25, 128 p-type Al _0.07 Ga _0.93 N cladding layer 26, 69, 115, 129, 149 p-type G
aN contact layer 27, 47, 70, 104, 130, 150
Insulating protective film 28, 48, 71, 95, 105, 116, 131, 1 made of SiO ₂
51, 170p side ohmic electrode 29, 49, 72, 96, 106, 117, 132, 1
52,171n side ohmic electrode 30,50,73,107 wiring electrode 42 n-type GaN contact layer 43 cold n-type Al _0.1 Ga _0.9 N buffer layer 44,92,102 n-type Al _0.08 Ga _0.92 N
Layers 45, 93, 103 p-type Al _0.08 Ga _0.92
N layer 46,94 AlN cap layer 61 AlGaN low temperature buffer layer 63 n-type Al _0.08 Ga _0.92 N cladding layer 64,124,164 n-type GaN guide layer 65,125 In _0.15 Ga _0.85 N / In _0.02
Ga _0.98 N multiple quantum well active layer (2 pairs) 66,126 p-type Al _0.2 Ga _0.8 N layer 67,127,167 p-type GaN guide layer 68 p-type Al _0.08 Ga _0.92 N cladding layer 90,100,110,120 , 140,160
n-type GaN substrate 91, 101 low-temperature n-type Al _0.1 Ga _0.9 N buffer layer 111 n-type Al _0.07 Ga _0.93 N low-temperature buffer layer 112 n-type Al _0.2 Ga _0.8 N cladding layer 113 Al _0.07 Ga _0.93 N active layer 114 p-type Al _0.2 Ga _0.8 N cladding layer 121, 141 n-type AlGaN low temperature buffer layer 122, 142 n-type Al _0.03 Ga _0.97 N high temperature buffer layer 143 n-type Al _0.15 Ga _0.85 N cladding layer 144 n-type Al _0.1 Ga _0.9 N guide layer 145 GaN / Al _0.1 Ga _0.9 N multiple quantum well active layer 146 p-type Al _0.2 Ga _0.8 N layer 147 p-type Al _0.1 Ga _0.9 N guide layer 148 p-type Al _0.15 Ga _0.85 N cladding layer 161 second buffer made of n-type GaN layer 162 n-type In _0.1 Ga _0.9 n anti-cracking layer 163 n-type Al _0.2 Ga _0.8 n / G Cladding layer made of N superlattice _{165 In 0.05 Ga 0.95 N / In} 0.2 Ga 0.8
N multiple quantum active layer well structure 166 p-type Al _0.3 Ga _0.7 N cap layer 168 p-type Al _0.2 Ga _0.8 N / GaN superlattice cladding layer 169 p-type GaN contact layer 201,202,700 light emitting facet 203,300, 500,600 Light receiving surface 400,800,900 Current constriction ridge structure 401,402,801,802,901,902
Optical cavity facet 1000,2000 Stacked structure of semiconductor laser

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tsuyoshi Miki 1-3-6 Nakamagome, Ota-ku, Tokyo F-term in Ricoh Co., Ltd. (Reference) 5F041 AA03 AA21 AA43 CA40 CA57 CA65 FF13 FF14 5F045 AA04 AB14 AB17 AC08 AC12 AD12 AD14 AF04 BB16 CA12 DA53 DA55 5F073 AA13 AA45 AA74 BA01 BA05 CA07 CB05 DA05 DA11 DA21 DA31 EA28

Claims (13)

[Claims] 1. A p-type Al _x Ga.sub. _(1-x) N doped with Mg.
(0 ≦ x ≦ 1), the p-type Al _x Ga _(1-x) N
(0 ≦ x ≦ 1), wherein B is added simultaneously with Mg. 2. A semiconductor device having a semiconductor multilayer structure including the group III nitride semiconductor according to claim 1. 3. The semiconductor device according to claim 2, wherein p
A semiconductor device comprising the group III nitride semiconductor according to claim 1 used for a contact layer forming a side ohmic electrode. 4. The semiconductor device according to claim 2, wherein said semiconductor device is a semiconductor light emitting element. 5. The semiconductor device according to claim 4, wherein said semiconductor light emitting device is a semiconductor laser device. 6. The semiconductor device according to claim 4, wherein the semiconductor light emitting element has an emission wavelength of 400.
a semiconductor device characterized by having a diameter of not more than nm. 7. A semiconductor device according to claim 5, wherein the semiconductor laser device as a semiconductor device has at least one pn junction using the group III nitride semiconductor according to claim 1 for a cladding layer. A semiconductor device. 8. A p-type A in which B is added simultaneously with Mg.
Crystal growth of l _x Ga _(1-x) N (0 ≦ x ≦ 1) is performed in a reaction system containing hydrogen gas, and cooling from the crystal growth temperature immediately after the crystal growth is performed in a cooling atmosphere containing a nitrogen source. A method for manufacturing a group III nitride semiconductor, comprising: 9. The method for manufacturing a group III nitride semiconductor according to claim 8, wherein the nitrogen source contained in the cooling atmosphere is N
A method for manufacturing a group III nitride semiconductor, which is H ₃ . The 10. p-type Mg simultaneously B is added _{Al x Ga (1-x)} N (0 ≦ x ≦ 1), and crystal growth in a reaction system containing a hydrogen gas, immediately after the crystal growth A method for producing a group III nitride semiconductor, wherein cooling from a crystal growth temperature is performed in a cooling atmosphere of NH ₃ . 11. A semiconductor laminated structure containing p-type Al _x Ga.sub. _(1-x) N (0.ltoreq.x.ltoreq.1 ₎ to which B is added simultaneously with Mg is crystal-grown in a reaction system containing hydrogen gas. A method for manufacturing a semiconductor device, wherein cooling from a crystal growth temperature immediately after the crystal growth is performed in an atmosphere containing a nitrogen source. 12. The method for manufacturing a semiconductor device according to claim 11, wherein the nitrogen source contained in the cooling atmosphere is NH _3.
A method for manufacturing a semiconductor device. 13. A semiconductor laminated structure containing p-type Al _x Ga.sub. _(1-x) N (0.ltoreq.x.ltoreq.1 ₎ to which B is added simultaneously with Mg is crystal-grown in a reaction system containing hydrogen gas. A method for manufacturing a semiconductor device, wherein cooling from a crystal growth temperature immediately after the crystal growth is performed in a cooling atmosphere of NH ₃ .