JPH10242586A - Group iii nitride semiconductor device and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain superior crystallinity and to prevent a crack from caused, by doping an n-type AlGaInN layer adjacent to a buffer layer with first impurities and second impurities. SOLUTION: In a group III nitride semiconductor device in which a plurality of layers comprising AlGaInN are laminated over a single-crystal substrate with a buffer comprising AlN in between, an n-type AlGaInN layer adjacent to a buffer layer is doped with first impurities comprising at least one out of C, Si, Ge and O, and second impurities comprising at least one out of Mg, Ca, Zn, Cd, Hg, S or Se.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to Al _x Ga
_{The present} invention relates to a group III nitride semiconductor device such as a light emitting element formed by laminating _1-xy In _y N (0 ≦ x, y and x + y ≦ 1) semiconductor thin films, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Al _x G which is a direct transition and whose optical energy gap can be controlled in the range of 1.9 to 6.2 eV.
A group III nitride semiconductor device such as a semiconductor laser or a light emitting diode using a _y In _1-xy N (0 ≦ x, y and x + y ≦ 1) -based material has been experimentally manufactured. Since large single crystals of GaN and AlN cannot be manufactured yet, the above-mentioned group III nitride semiconductor device does not always have good matching of lattice and thermal expansion coefficient. However, sapphire (Al ₂ O ₃ ) and spinel (MgAl ₂ O ₄ ) is widely used as a substrate. And silicon (Si) and magnesium (M
g) control of n-type and p-type valence electrons by adding
_{Al x Ga y In 1-xy} N ( hereinafter, also sometimes referred to as the AlGaInN) which enables control of the optical energy gap by changing the value of x and y in.

A recent example of a group III nitride semiconductor device is as follows.
Two. Fig. 6 shows the conventional simplest double hetero (D
H) is a sectional view of a light emitting device having a structure (S. Nakamura et a.)
l. Japanese Journal of Applied Physics, vol32 (199
3), L8-L11). First, a buffer layer 2 made of low-temperature GaN formed at a low temperature of 400 to 500 ° C. is formed on a sapphire substrate 1 having a (0001) plane. Less than,
A thickness of 300 made of n-type GaN at a high temperature of about 1000 ° C.
A first cladding layer 4 also serving as an underlayer of 0 nm, p-type Ga
An active layer 5 of InN having a thickness of 20 nm and a second cladding layer 6 of p-type GaN are sequentially laminated. On the second cladding layer 6, a p-side electrode layer 7a is formed. Since the sapphire substrate 1 is an insulator, a part of the active layer 5 to the second cladding layer 6 is removed by etching or the like, and an n-side electrode layer 7b is formed on the exposed first cladding layer 4. The four sides of the etched or cut active layer are light emitting surfaces.

FIG. 7 is a cross-sectional view of a conventional multiple quantum well (MQW) laser diode (S. Nakamura et al.).
l. Japanese Journal of Applied Physics, vol32 (199
3), L74-L76). The substrate surface of the substrate 1 is made of sapphire (00
01) plane. First, the buffer layer 2 made of n-type GaN is used as an initial layer, and then, a base layer 3 made of n-type GaN, a crack suppression layer 3a made of n-type InGaN, a first clad layer 4 made of n-type AlGaN, and an n-type An optical guide layer 4a made of GaN, an active layer 5q having a multiple quantum well structure made of p-type GaInN, a decomposition suppressing layer 6b made of p-type AlGaN, an optical guide layer 6a made of p-type GaN, and a p-type G
A second cladding layer 6 made of aN and a contact layer 7 made of p-type GaN are sequentially stacked. A p-side electrode layer 8a made of Au / Cr is formed on the contact layer 7, and an n-side electrode layer 8b made of Al is formed on the back side of the substrate 1.

In either case, the buffer layer is formed on the substrate and then the underlayer is formed thick to improve the crystallinity of the underlayer.

[0006]

Generally, when a c-axis oriented film of a material having a hexagonal structure is formed or grown on a substrate, the growth rate on the substrate is not uniform depending on the direction but is three-dimensional. It is known that it tends to grow (island growth). Similar facts are observed also in the _{Al x Ga y In 1-xy} N is hexagonal. Such a film has very large surface irregularities and poor crystallinity. In order to avoid this, by using an AlN film having a relatively weak tendency or a GaN film grown at a low temperature as a buffer layer, growth in the a-axis direction is promoted to some extent, and surface flatness and
A film with good crystallinity can be obtained. However, the quality of the film obtained using the buffer layer is still insufficient as a laser diode, and when a large current is injected, grain boundaries caused by island growth (crystal grain boundaries that are collision interfaces between the grown islands) are obtained. It has also been reported that the electrode material is diffused along. Therefore, in order to obtain a good quality laser diode, it is necessary to further promote the growth in the a-axis direction.

Also, AlGaN has a strong tendency to grow three-dimensionally more than a GaN film. Therefore, the growth of the AlGaN cladding layer requires a thin buffer layer and a thick GaN layer of 1 μm or more on a substrate for the purpose of improving crystallinity. This is performed on two layers of the underlayer composed of Second conventional example (FIG. 6)
, A 100 nm GaInN layer is further formed as a crack suppression layer on the underlayer.

However, when a substrate having a thermal expansion coefficient smaller than that of a GaAlInN-based material or a substrate having a lattice constant smaller than that of a GaAlInN-based material is used, tensile stress is generated in the GaAlInN film, and Al
Cracks occur in the GaInN film depending on the overall thickness. For example, when an AlN buffer layer was formed to a thickness of 6 nm on a Si (111) substrate and a GaAlInN film was formed thereon, cracks were observed when the GaAlInN film thickness was 1.5 μm or more. When manufacturing a laser diode, the thickness of the cladding layer is set to 500 to have an optical confinement effect.
In the DH structure, the active layer is sandwiched between two layers of the n-type and p-type cladding layers. Therefore, even when the thickness of the active layer is about 50 nm, the cladding and the active layer have a thickness of 1050 nm.
nm. In the actual device structure, the GaN layer described above enters under the n-type cladding layer, and the p-type cladding layer is formed on the p-type cladding layer to improve the contact of the electrode with the p-type.
The total film thickness is 3 μm
Get closer. With this film thickness, cracks are definitely generated when Si is used for the substrate.

One of the methods for suppressing the generation of cracks is to reduce the thickness of the semiconductor device. If the n-type cladding layer can be formed directly on a thin buffer layer formed on a substrate, Cracks can be prevented.
To form the n-type cladding layer directly on the buffer layer,
It is necessary to suppress three-dimensional growth (island growth) by some method and promote two-dimensional growth (growth in the a-axis direction).

It is an object of the present invention to provide a group III nitride semiconductor device having good crystallinity and a method of manufacturing a group III nitride semiconductor device free from cracks.

[0011]

In order to achieve the above-mentioned object, Al _x Ga _{1 -xy} In _y N (however, provided on a single crystal substrate via a buffer layer made of GaN or AlN).
0 ≦ x ≦ 1, 0 ≦ y ≦ 1, and x = y = 0) in a group III nitride semiconductor device having an n-type Al _x Ga ₁ layer adjacent to the buffer layer. _-xy
In the In _y N layer, magnesium (Mg), calcium (Ca), and zinc (C), silicon (Si), germanium (Ge), and oxygen (O) together with a first impurity formed of at least one or more thereof. Zn), cadmium (C
d), mercury (Hg), sulfur (S), or selenium (S
It is assumed that at least one second impurity of e) is added.

The concentration of the first impurity is 1 × 10 ¹⁷ cm ^−3.
To 2 × 10 ¹⁹ cm ⁻³ , and the concentration of the first impurity is preferably 1 × 10 ¹⁵ cm ⁻³ to 2 × 10 ¹⁷ cm ⁻³ .
The substrate is preferably made of a single crystal of silicon, germanium, or silicon carbide. Here, when these single-crystal substrates are used as electrodes, the carrier concentration of the substrate is preferably adjusted to 10 ¹⁸ to 10 ²⁰ cm ⁻³ in order to reduce the resistance.

The group III nitride semiconductor device is a light emitting device including an n-type cladding layer such as a light emitting diode or a laser diode, an active layer and a p-type cladding layer, and the n-type cladding layer is the n-type Al _x Ga _{1. -xy} In _y N layer is preferable. In the method of manufacturing a group III nitride semiconductor device, the film of Al _x Ga _{1 -xy} In _y N is formed by molecular beam epitaxy.

Preferably, among the first impurities, silicon (Si) and germanium (Ge) and the second impurity are supplied from an effusion cell. Preferably, the carbon (C) is evaporated by electron beam irradiation. The oxygen (O) is preferably introduced into the same high-frequency-excited radical generating source as the group III nitride raw material nitrogen (N).

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION In relation to GaN growth, in particular, from the simulation of the relationship between the respective amounts of fluxes of Ga and N supplied to the substrate surface and the crystal surface during crystal growth and the mechanism of crystal growth, the Ga flux It has been reported that when the amount is larger than the amount of N flux, two-dimensional growth is promoted (K. Wang et al, Journal Applied Physics vol.
76 (1994), 3502-3510). This is because considering the migration of particles on the substrate at a constant substrate temperature, the non-polar Ga single particles are more likely to have polar G particles.
It is described that the substrate surface and the crystal surface during the crystal growth are less affected by the aN molecule particles than the state of the aN molecules, and therefore the migration becomes easier.

However, if the amount of Ga flux is excessive, it will deposit on the film surface in the state of Ga metal. The present invention is intended to flux a metal having a high vapor pressure so as not to be deposited on the film by re-evaporation even if it is supplied in an excessive amount, and another metal which does not cause a defect in the crystal even when incorporated in the film, simultaneously with Ga. It is based on the finding that the above-mentioned precipitation of Ga can be prevented by supplying, and two-dimensional growth can be promoted. In addition, such a crystal growth situation is that the same crystal structure of Al
There is no change in N, InN and their mixed crystal (AlGaInN) system.

Elements satisfying the above two conditions include magnesium (Mg), calcium (Ca), zinc (Zn), cadmium (Cd), mercury (Hg), sulfur (S), and selenium (Se). FIG. 5 is a graph showing the temperature dependence of the vapor pressure of the added element (REHonig and DAK).
ramer, RCA Review vol 30,285 (1969)). AlGaInN
At around 800 ° C., which is the film forming temperature of the system material, since the vapor pressure of these elements is higher than Ga by 10 ⁴ or more, most of them easily re-evaporate even when they reach the substrate. Also, AlG
Even if a small amount of these elements are mixed in the aInN-based film,
Since g, Ca, Zn, Cd, and Hg substitute as Ga sites and act as acceptors, and S and Se act as donors, it is considered that the crystallinity of the base material does not deteriorate. Example 1 As Example 1 of the present invention, A
GaN with Si and Mg added via 1N buffer
A film was formed. The film formation method is a molecular beam epitaxy (MBE) method, and Al metal, Ga metal, Si, Mg
Each metal was charged into a separate effusion cell as a starting material, and heated to obtain each metal vapor flux. In addition, a nitrogen radical flux was obtained using a nitrogen radical source excited by high frequency. First, S
Al vapor flux and nitrogen radical flux are simultaneously irradiated on the i (111) plane substrate to form an AlN film having a thickness of about 6 nm.
A buffer layer was formed. The substrate temperature was 840 ° C. Next, the shutters of the respective effusion cells for Ga, Si, and Mg were simultaneously opened and irradiated simultaneously with the nitrogen radical flux to form a GaN film to which Si and Mg were added. Substrate temperature is 840 ° C which is the same as AlN buffer layer
And the cell temperatures of Ga, Si and Mg are 1080
° C, 1150 ° C, and 420 ° C. For comparison,
Conventional film formation without adding Mg was also performed. In each case, the GaN film thickness was 670 nm.

FIG. 1 is a photomicrograph (SEM photograph) showing a cross section of a GaN film on an AlN buffer layer according to the present invention. FIG. 1A shows a case where both Mg and Si according to the present invention are added. (B) is a case where only conventional Si is added. In (b), the GaN film surface has irregularities, but in (a), it is flat. It can be seen that simultaneous addition of Si and Mg promotes the growth in the a-axis direction and flattens the film surface. In the measurement of the half-width of the rocking curve of the (0001) plane by X-ray diffraction of these films, the half-width of the film to which Mg was not added was 15 minutes, whereas the half-width of the film to which Mg was added was 7 minutes. It was confirmed that the addition improves the crystallinity even when the film thickness is 1 μm or less.

As a result of composition analysis by SIMS, it was found that the concentration of Mg in the film was 2 × 10 ¹⁷ cm ⁻³ , while the concentration of Si in the film was 2 × 10 ¹⁹ cm ⁻³ . Further, as a result of the carrier concentration measurement by the hole measurement, the carrier concentration was about 2 × 10 ¹⁹ cm regardless of whether Mg was added or not.
^{Was -3} . Further, the Mg concentration with respect to the Si concentration is 1%.
An experiment was performed in which the Si concentration was changed while
In the range of i concentration of 1 × 10 ^{17 to} 2 × 10 ¹⁹ cm ⁻³ , the improvement of the film quality by the addition of Mg as described above was observed.

Further, as a result of an experiment conducted by changing only the Mg concentration, when the Mg concentration exceeds 2 × 10 ¹⁷ cm ⁻³ , the electron mobility is reduced, and the Mg concentration is 2 × 10 ¹⁵ cm ⁻³ or less. No remarkable improvement in film quality due to the addition of Mg could not be observed. Example 2 Using carbon (C) instead of Si as a donor impurity, a GaN film was formed by adding Mg and C at the same time. Note that carbon was heated and evaporated by electron beam irradiation. In the case where C is used as the donor impurity,
Mg concentration 2 × 10 ¹⁵ cm ⁻³ to 2 × 1
In the range of 0 ¹⁷ cm ^-3 , an improvement in the GaN film quality due to the addition of Mg was observed.

When the Mg concentration exceeds 2 × 10 ¹⁷ cm ⁻³ , the electron mobility decreases, and the Mg concentration is 2 × 10 ¹⁵ cm ^−3.
Below ^-3 , no remarkable improvement in film quality due to the addition of Mg could not be observed. Example 3 As a donor impurity, germanium (G) was used instead of Si.
Using e), a GaN film to which Mg and C were added simultaneously was formed. Ge was heated by an effusion cell like Si. When Ge is used as the donor impurity, similarly to the case of Si, the Mg concentration is 2 × 10 ¹⁵ cm ⁻³ to 2 ×.
In the range of 10 ¹⁷ cm ^-3 , the improvement of the GaN film quality due to the addition of Mg was observed. When the Mg concentration was 2 × 10 ¹⁵ cm ⁻³ or less, no remarkable improvement in film quality due to the addition of Mg could not be observed.

When the Mg concentration is 2 × 10¹⁷cm^-3Cross over
And the electron mobility decreased, and the Mg concentration was 2 × 10^Fifteencm
^-3Below, a remarkable improvement in film quality due to the addition of Mg can be observed.
Did not. Example 4 Using oxygen (O) instead of Si as a donor impurity
To form a GaN film with simultaneous addition of Mg and C
Was. Oxygen is supplied to the nitrogen radical source via a flow meter.
And irradiate the film as oxygen radicals with nitrogen radicals.
Fired. When oxygen is used as the donor impurity,
As in the case, the Mg concentration is 2 × 10^Fifteencm^-3~ 2 × 10¹⁷cm^-3
In the range, the improvement of the GaN film quality due to the addition of Mg was observed.
Was. Example 5 Calcium (Ca) was used instead of Mg, and Ca and Si
Was simultaneously added to produce GaN. Using Ca
Also in the case, similarly to Mg, the Ca concentration is 2 × 10^Fifteen~ 2 × 1
0¹⁷cm^-3Improvement of film quality by addition of Ca was observed in the range of
Was. Example 6 Instead of Mg, zinc (Zn) was used, and Zn and Si were simultaneously
A GaN film added to the substrate was formed. When using Zn
Also, like Mg, the Zn concentration is 2 × 10^Fifteen~ 2 × 10¹⁷
cm^-3Improvement of film quality by addition of Zn was observed in the range of
Was. Example 7 Cd and Si were replaced by cadmium (Cd) instead of Mg.
Was simultaneously added to produce GaN. Using Cd
Also in the case, similarly to Mg, the Cd concentration is 2 × 10^Fifteen~ 2 × 1
0¹⁷cm^-3Improvement of film quality by addition of Cd was observed in the range of
Was. Example 8 Mercury (Hg) was used instead of Mg, and Hg and Si were simultaneously used.
Was formed. When using Hg
Also has an Hg concentration of 2 × 10^Fifteen~ 2 × 10¹⁷cm
^-3The improvement of the film quality by the addition of Hg was observed in the range of. Example 9 S (Si) was used instead of Mg, and S and Si were added simultaneously.
A film of the added GaN was formed. When S is used, M
g, S concentration 2 × 10^Fifteen~ 2 × 10¹⁷cm ^-3Range
As a result, an improvement in film quality due to the addition of S was observed. Example 10 Selenium (Se) was used instead of Mg, and Se and Si were the same.
A film of GaN that was sometimes added was formed. Using Se
In this case, similarly to Mg, the Se concentration is 2 × 10^Fifteen~ 2 × 1
0¹⁷cm^-3Improvement of film quality by addition of Se was observed in the range of
Was. Example 11 In this example, the n-type clad material Al_0.2Ga
_0.8Regarding the N film, the same as the GaN film in Example 1
A film was formed.

FIG. 3 shows a conventional AlG buffer on an AlN buffer layer.
It is a microscope photograph (SEM photograph) which shows a section of aN film.
The Al _0.2 Ga _0.8 N film has a strong tendency to grow in an island shape more than GaN, and when formed directly on a Si (111) plane substrate via an AlN buffer layer, the unevenness is severe as shown in FIG. A film is obtained. To avoid this unevenness,
Normally, as described in the example of the prior art, GaN is first deposited on the AlN buffer layer, and Al _0.2 Ga
_{A 0.8} N film was formed. However, with a donor impurity such as Si, a concentration of 1 × 10 ¹⁵ to 2 × 10 ¹⁷ cm ⁻³ of M
It was found that when g was added at the same time, the effect of improving the crystallinity obtained in the GaN film formation can be achieved also in the Al _0.2 Ga _0.8 N film. FIG. 2 is a micrograph (SEM) showing a cross section of the AlGaN film of the present invention in which Si and Mg are simultaneously added.
Photo). It can be seen that there is no severe unevenness and the surface is extremely flat.

This effect is similar to that of the first embodiment.
In addition to i, C, Ge and O were obtained in combination with calcium (Ca), zinc (Zn), cadmium (Cd), mercury (Hg), sulfur (S), or selenium (Se). Based on the results, the following laser diodes were prototyped. FIG. 4 is a cross-sectional view of a laser diode having a DH structure using an AlGaN film in which Si and Mg are simultaneously added according to the present invention. 500 nm thick n-type Al _0.2 Ga _0.8 N obtained by simultaneously adding Si and Mg to an n-type Si (111) substrate 1 via an AlN buffer 2 having a thickness of 6 nm
First cladding layer 4 having a thickness of 50 made of undoped GaN
nm active layer 5, p-type Al _0.2 Ga doped only with Mg
_A 500 nm thick second cladding layer 6 made of _0.8 N, Mg
A 100-nm-thick contact layer 7 made of p-type GaN to which only N was added was laminated. The contact layer 7 has Cr
The p-side electrode 8a of / Au was formed, and the n-side electrode 8b of Al was formed on the back side of the substrate 1. By cleaving the (111) plane of the Si substrate, the (1-100)
The surface was cleaved, and this cleaved surface was used as an optical resonance surface of the optical resonator.
In this DH device, the thick GaN layer, which was conventionally required, could be omitted, so that the entire film thickness could be reduced to 1150 nm, and no crack was generated in the film.

When a pulse current was passed from p-type GaN to the Si (111) substrate at room temperature, laser oscillation could be observed at a current of 800 mA or more. Example 12 The same DH structure as in Example 11 was produced by using an n-type Ge (111) or SiC (0001) plane instead of the Si (111) substrate in Example 11, and similar results were obtained. Was.

[0026]

According to the present invention, GaN is formed on a single crystal substrate.
Alternatively, Al _x Ga is applied through a buffer layer made of AlN.
_1-xy In _y N (where 0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x
= Y = 0) III
In the group nitride semiconductor device, at least one of carbon (C), silicon (Si), germanium (Ge), and oxygen (O) is provided in the Al _x Ga _{1 -xy} In _y N layer adjacent to the buffer layer. And at least one of magnesium (Mg), calcium (Ca), zinc (Zn), cadmium (Cd), mercury (Hg), sulfur (S), or selenium (Se) together with a first impurity of Since the second impurity is added, the crystallinity and morphology of the film are improved, and a high-quality Group III nitride semiconductor device such as an LED or a semiconductor laser can be obtained.

[Brief description of the drawings]

FIG. 1 is a micrograph (SEM photograph) showing a cross section of a GaN film on an AlN buffer layer according to the present invention, wherein (a) shows a case where both Mg and Si according to the present invention are added, and (b)
Is the case with only conventional Si addition

FIG. 2 shows the AlGa with simultaneous addition of Si and Mg according to the present invention.
Micrograph (SEM photograph) showing a cross section of the N film

FIG. 3 is a micrograph (SEM photograph) showing a cross section of an AlGaN film on a conventional AlN buffer layer.

FIG. 4 shows the AlGa with simultaneous addition of Si and Mg according to the present invention.
Sectional view of a laser diode having a DH structure using an N film

FIG. 5 is a graph showing the temperature dependence of the vapor pressure of an additive element.

FIG. 6 is a cross-sectional view of a conventional simplest light emitting element having a double hetero (DH) structure.

FIG. 7 is a sectional view of a conventional laser diode having a multiple quantum well (MQW) structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Buffer layer 3 Underlayer 3a Crack suppression layer 4 First clad layer 4a First light guide layer 5 Active layer 6 Second clad layer 6a Second light guide layer 6b Decomposition suppression layer 7 Contact layer 8a P-side electrode 8b n Side electrode

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Hideaki Matsuyama 1-1, Tanabe-Nitta, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Inside Fuji Electric Co., Ltd. (72) Inventor Hiroshi Kamijo 1st Tanabe-Nita, Kawasaki-ku, Kawasaki-ku, Kanagawa Prefecture No. 1 Fuji Electric Co., Ltd.

Claims (8)

[Claims] An Al _x Ga _{1 -xy} In _y N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x = y = 0) is provided on a single crystal substrate via a buffer layer made of GaN or AlN. ), The n-type Al _x Ga adjacent to the buffer layer.
_1-xy In _y N is the layer of carbon (C), silicon (S
i) magnesium (Mg), calcium (Ca), zinc (Zn), cadmium (Cd), mercury (Hg), together with a first impurity comprising at least one of germanium (Ge) and oxygen (O). A group III nitride semiconductor device, wherein a second impurity comprising at least one of sulfur (S) and selenium (Se) is added. 2. The method according to claim 1, wherein the concentration of the first impurity is 1 × 10 ¹⁷ cm ^-3.
To a 2 × 10 ¹⁹ cm ^-3, III nitride according to claim 1 the concentration of said first impurity, characterized in that 1 × 10 ¹⁵ cm ^-3 to a 2 × 10 ¹⁷ cm ^-3 Object semiconductor device. 3. The group III nitride semiconductor device according to claim 1, wherein said substrate is made of a single crystal of silicon, germanium, and silicon carbide. 4. The group III nitride semiconductor device is a light emitting device including an n-type cladding layer such as a light-emitting diode or a laser diode, an active layer and a p-type cladding layer, wherein the n-type cladding layer is the n-type Al _x 4. The group III nitride semiconductor device according to claim 1, wherein the group III nitride semiconductor layer is a Ga _1-xy In _y N layer. 5. The method of manufacturing a group III nitride semiconductor device according to claim 1, wherein said Al _x Ga _{1 -xy} I
method for producing a group III nitride semiconductor device, wherein the deposition of the n _y N is by molecular beam epitaxy. 6. The group III nitride according to claim 6, wherein, among said first impurities, silicon (Si) and germanium (Ge) and said second impurity are supplied from an effusion cell. A method for manufacturing a semiconductor device. 7. The method for manufacturing a group III nitride semiconductor device according to claim 6, wherein said carbon (C) is evaporated by electron beam irradiation. 8. The group III nitride semiconductor device according to claim 6, wherein said oxygen (O) is introduced into a radical generator of the same high frequency excitation as nitrogen (N) as a source of group III nitride. Manufacturing method.