JP2001313418A - GaN-BASED LIGHT-EMITTING ELEMENT AND ITS CREATION METHOD - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high quality GaN-based light-emitting element, in which a GaNP layer or a GaNAs layer is used as an active layer and to provide its formation method. SOLUTION: The GaN-based light-emitting element is constituted, in such a way that the GaNP layer which is changed into a mixed crystal by executing heat treatment is used as the active layer with reference to a multilayer film 30', which is constituted by laminating GaN layers and GaP layers. Instead of the GaP layers, the GaNP layer may be formed by laminating GaAs layers and the GaN layers.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a GaN-based light-emitting device for producing a light-emitting device composed of a GaN-based compound semiconductor and a method for producing the same.

[0002]

2. Description of the Related Art GaN (gallium nitride) is a material belonging to a group III-V nitride semiconductor according to the classification of compound semiconductors based on the periodic table, and has a hexagonal wurtzite type crystal structure. Structure. Other materials belonging to this group III-V nitride semiconductor include aluminum nitride (Al
N) and indium nitride (InN). Since all of these have direct transition energy band structures, Si
It is known as a material having essentially excellent characteristics in terms of luminous efficiency as compared with a material belonging to the indirect transition type such as C.

Further, these mixed crystals (Al, Ga,
In) N can change the band gap energy Eg in a wide range from 1.95 to 6.28 eV depending on the mixed crystal ratio. Therefore, there is a possibility that all colors in the visible region from ultraviolet to red can be realized as colored light. In addition, high melting point, high hardness,
Since features such as high thermal conductivity can be a highly reliable device having excellent environmental resistance, it is particularly promising as a material for a light emitting device.

[0004] As described above, a GaN-based compound semiconductor has a sufficient potential as a light-emitting material, and particularly has blue color light, so that an ultraviolet light-emitting diode (LED) can be realized. Therefore, by combining this with existing red and green LEDs, LE
It is also possible to realize a full-color display using D.

In general, when producing an LED or LD (laser diode), in order to obtain a thin film by epitaxial growth, a substrate to be used is required to have a lattice constant which is sufficiently high matching with a light emitting material. If this requirement is not satisfied, the crystal structure of the thin film is different from the crystal structure of the substrate, and a mismatch occurs in the lattice constant. Will be invited.

However, in the production of GaN-based LEDs, there are no commercially available substrates for epitaxial growth with matching lattice constants, and even in a sapphire substrate actually used for growth, the lattice constant is shifted by almost 15%. ing. For this reason, it is very difficult to grow a high-quality crystal, and it has been long in the past that no technological progress has been made as a light-emitting element.

In order to grow GaN, the substrate needs to be
2,000 ° C., but at this temperature the vapor pressure of GaN increases,
It is extremely difficult to improve the crystallinity of the film,
GaN also had a problem that a p-type crystal could not be formed, which made it more difficult to realize a GaN-based light emitting device.

Against this background, it has recently been found that, when a thin buffer layer is first formed of AlN or GaN on a substrate and then a GaN film is grown, the crystallinity is dramatically improved. This solves the problem of crystallinity due to lattice mismatch. In addition, it has been found that a low-resistance p-type GaN film is formed by irradiating an electron beam or performing a thermal annealing process on the Mg-doped GaN film. As a result, a pn junction of a GaN-based material is now feasible, and a mixed crystal film of InGaN or the like can be obtained.

[0009] In the following, G is used as an active layer having an n-type GaN layer.
A typical method for producing an aN-based LED will be described. G
The aN-based LED is provided as a thin-film multilayer structure.
Here, MOCVD (Me
tal-Organic Chemical Vapo
(r Deposition) method will be described.

First, when fabricating a GaN-based LED, an AlN buffer layer is grown on a semi-insulating sapphire substrate or a conductive SiC substrate using ammonia (NH ₃ ) and trimethyl aluminum (TMA).

Further, trimethylgallium (T
MG) with ammonia (NH ₃ ) and silane (SiH ₄ )
Is used as a gas source to grow a Si-doped n-type GaN layer at a growth temperature of 1050 ° C. Further, on top of that, TMA is added to the above raw material, and at a growth temperature of 1050 ° C,
An n-type AlGaN layer functioning as a cladding layer is grown. Then, an n-type GaN layer serving as an active layer is formed thereon at the same temperature using TMG, NH ₃ and SiH ₄ as gas raw materials.

Further, a p-type AlGaN layer serving as another clad layer is grown at the same temperature using cyclopentadienyl magnesium (CpMg) as a dopant. Finally, a p-type GaN layer is grown at the same temperature using biscyclopentadienyl magnesium (bCpMg) as a dopant.

As described above, the laminated film constituting the LED is:
A buffer layer deposited at low temperature on a sapphire substrate, n
It is general that the order is low-resistance layer, n-type cladding layer, active layer, p-type cladding layer, and p-type low resistance layer.

After laminating the above thin film, SiO ₂ or the like is deposited on the surface thereof by using a plasma CVD apparatus in order to perform patterning for forming an electrode, and then a photoresist and a photoresist are formed to form an n-type electrode. Etching and patterning using chemical etching or the like. in this case,
An n-type electrode is formed by etching a part of the n-type GaN and depositing a metal such as Ti / Al on the upper surface thereof. On the other hand, the p-type electrode is formed by evaporating a metal such as Au / Ni on the upper surface of the above-described p-type GaN.

Thus, a GaN having an active layer of GaN
The system LED has a well-established manufacturing method and can function as a light emitting element with sufficiently high luminance, but has a problem that a large number of lattice defects exist in the GaN layer. In particular, a large number of lattice defects due to nitrogen vacancies were present, which was a major problem as a non-luminescent center.

In view of this, GaN having InGaN as an active layer
System LED, the method of making it has been established,
Since high-luminance light emission can be obtained by the formation of a light emission center by addition of In, it is widely marketed as an actual product. However, L using this InGaN as an active layer
In ED, blue-violet light emission satisfies sufficient practical use,
When trying to realize other colors by changing the doping amount of In, only emission up to orange was confirmed at most on the long wavelength side, and red emission, which is one of the basic colors of RGB, was realized. It has not been done yet. That is, only the LED using InGaN as the active layer has not realized light emission of all basic colors of RGB by changing the doping ratio.

However, in recent years, phosphorus (P) or arsenic (A
It has been found that a GaN-based material added with s) is also promising as a material for a blue LED. Depending on the doping amount of the additive, GaNP or GaNAs doped with these additives can develop a wide range of colors from ultraviolet to red.
It is expected that light emission of all GB basic colors will be realized. In particular, As and P added to GaN reduce lattice defects in GaN and act as an emission center, and are effective in increasing GaN band edge emission.

For example, GaNAs has an As content of 10% or less.
By adding, color development from ultraviolet to red is possible,
GaNP can be colored from ultraviolet to infrared by adding P within 15%.

[0019]

However, GaP
And GaAs have a small energy gap with a substantially linear variation range with respect to the doping amount of P or As,
As described above, there is a problem that the energy gap of NAs and GANP changes greatly with respect to the doping amount of P and As, and the form of the change is non-linear, so that it is difficult to control the energy gap.

In the formation of a thin film, it is known that atoms and molecules that have collided with the surface of the substrate or the thin film are partially reflected, and the others remain on the surface. The atoms and molecules remaining on the surface undergo surface diffusion (migration) with their own energy and the energy of the substrate temperature, some re-evaporate (detach), and others settle in a potential valley (adsorption). . That is, in order to form a thin film, it is necessary to reduce desorption of material atoms and molecules and to sufficiently migrate and adsorb the entire substrate.

However, GaNP and GaNAs are
When a film is formed by the OCVD method or the like, when the substrate is at a high temperature of about 1000 ° C., P or As is easily desorbed, and there is a problem that it is difficult to obtain high-quality GNP or GNAs. Therefore, there has been a problem that a high quality active layer cannot be obtained and the luminous efficiency is low.

[0022] The occurrence of this desorption is caused by GaNP or GaNAs.
And the crystal structure of a sapphire substrate or the like are inconsistent. Therefore, even if a buffer layer is interposed, P and As remain on the substrate in a relatively high temperature state of about 1000 ° C. for a long time. It was due to being unable to stay in the fixed position. In the following, the term “migration” refers to a state of surface adsorption required to obtain a desired mixed crystal such as GANP or GANAs.

The present invention has been made in view of the above, and has been made in consideration of the above-mentioned problems.
It is an object of the present invention to provide a system light emitting device and a method for manufacturing the same.

[0024]

In order to achieve the above-mentioned object, the invention according to claim 1 is characterized in that a multi-layered film in which a GaN layer and a GaP layer are alternately laminated is subjected to a heat treatment. Characterized in that it has a structure in which a GaNP layer is used as an active layer.

According to the present invention, the state after heat treatment is performed on the multilayer film formed by laminating the GaN layer and the GaP layer is used as the GNP layer functioning as the active layer. Enables the multi-wavelength light emission by the GaNP layer added with.

Further, the invention according to claim 2 has a structure in which a GaNAs layer which is mixed and crystallized by performing a heat treatment on a multilayer film in which GaN layers and GaAs layers are alternately stacked is used as an active layer. It is characterized by.

According to the present invention, the state after the heat treatment is applied to the multilayer film formed by laminating the GaN layer and the GaAs layer is used as the GaNAs layer functioning as the active layer. Enables multi-wavelength light emission by the GaNAs layer to which is added.

Further, the invention according to claim 3 is a structure in which the active layer is made of a GaNAs layer mixed and crystallized by performing a heat treatment on a multilayer film in which GaN layers and GaAs layers are alternately laminated. It is characterized by.

According to the present invention, the GaN layer and the GaASP
Since the GaNASP layer functioning as an active layer after the heat treatment is performed on the multilayer film formed by stacking the layers, the multi-wavelength light emission by the GaNASP layer to which enough AS and P are added is performed. Make it possible.

According to a fourth aspect of the present invention, in the GaN-based light-emitting device according to the first, second or third aspect, the GaN layer is the other Ga mixed crystal layer constituting the multilayer film together with the GaN layer. It is characterized by being larger than the thickness.

According to the present invention, the Ga mixed crystal layer such as GaP is formed extremely thin, so that when heat treatment is performed, the decomposition of the Ga mixed crystal layer is promoted, and the group V atoms contained therein are diffused. Mixed crystal formation can be promoted.

According to a fifth aspect of the present invention, there is provided a method of manufacturing a GaN-based light-emitting device in which a GaN-based light-emitting device is formed as a laminated structure of thin films by a vapor phase growth method. Forming a first low-resistance layer, forming a mask for forming at least one opening on the first low-resistance layer, and forming the first low-resistance layer and the mask on the first low-resistance layer. Above, second
Forming a low-resistance layer, and forming a cladding layer on the second low-resistance layer.

According to the present invention, the low-resistance layer formed on the buffer layer is constituted by the first low-resistance layer serving as a base and the second low-resistance layer selectively grown by using a mask. Therefore, the occurrence of dislocations in the second low-resistance layer is reduced, and by using this second low-resistance layer as a low-resistance layer for providing an electrode, a higher-quality GaN-based light-emitting element can be obtained. Can be.

The invention according to claim 6 is the invention according to claim 5
In the method of manufacturing a GaN-based light emitting device described in the above, the second low resistance layer is thicker than the first low resistance layer.

According to the present invention, since the second low-resistance layer is thicker than the first low-resistance layer, more high-quality low-resistance layers can be obtained.

[0036]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a GaN-based light emitting device and a method of manufacturing the same according to the present invention will be described below in detail with reference to the drawings. The present invention is not limited by the embodiment.

Embodiment 1 First, a GaN-based light emitting device according to the first embodiment and a method for manufacturing the same will be described. In particular, the first embodiment relates to a gas source MBE (Mol
1 shows a GaN-based light-emitting device formed by a method according to an E. C. e.

FIG. 1 is a sectional view of a GaN-based light emitting device according to the first embodiment. In particular, the GaN-based light emitting device shown in FIG.
An LED structure with aNP is shown. As shown in FIG. 1, the GaN-based light emitting device according to the first embodiment includes an n-type AlGaN layer 26 as a cladding layer and a p-type AlGaN
The n-type GaN layer 27 and the p-type GaN layer 24 are stacked on these cladding layers, respectively.

The n-type electrode 11 is formed on the upper surface of the n-type GaN layer 27, and the p-type GaN layer 24 has
A mold electrode 12 is formed. Therefore, macroscopically, the GaN-based light emitting device according to the first embodiment has an n-type low-resistance layer, an n-type cladding layer, a non-doped active layer, a p-type cladding layer, and a p-type low-resistance layer stacked in this order. The active layer of the conventional GaN-based light emitting device is made of non-doped GNP.
This is merely a structure in which the layers are replaced by layers, but as described above, Ga
Mixed crystals of N and P are difficult. Therefore, the GaN-based light emitting device according to the first embodiment is a non-doped GNP.
In forming the layer, that is, the GaNP multilayer film 30 ′,
A device for avoiding the above-described difficulty of mixed crystal formation is provided.

Next, the procedure for manufacturing the GaN-based light-emitting device shown in FIG. 1 will be described, including the above-described contrivance on the GANP multilayer film 30 '. FIG. 2 is a flowchart illustrating a procedure for manufacturing the GaN-based light emitting device according to the first embodiment. FIGS. 3 and 6 are cross-sectional views for explaining a GaN-based light emitting device created according to the flowchart shown in FIG. Note that an ultra-high vacuum apparatus having a growth chamber and a patterning chamber is used as the gas source MBE apparatus.

First, a sapphire substrate, a crystal substrate such as a SiC or silicon substrate is placed on a susceptor in a growth chamber. Here, a silicon substrate is used as the crystal substrate. Then, in this state, the temperature of the silicon substrate is maintained at 640 ° C., and the formation of the p-type GaN buffer layer is started (step S101).

This p-type GaN buffer layer 21 is made of dimethylhydrazine (DMH) having a vapor pressure of 5 × 10 ⁻⁵ Torr.
Using a molecular beam of Ga and Mg having a vapor pressure of 5 × 10 ⁻⁷ Torr, a 50 ° thick crystal structure doped with Mg is formed on the silicon substrate 20 (FIG. 3).
(A)).

Subsequently, the substrate temperature is maintained at 850 ° C.
A p-type GaN layer is formed (Step S102). The p-type GaN layer 22 is made of ammonia (NH ₃ ) having a vapor pressure of 5 × 10 ⁻⁶ Torr and Ga having a vapor pressure of 5 × 10 ⁻⁷ Torr.
And a 1 μm thick Ga doped with Mg on the p-type GaN buffer layer 21 using a molecular beam of Mg and Mg.
It is obtained as an N layer (FIG. 3B). Here, the p-type GaN layer 22 is referred to as a first p-type GaN layer.

Here, the n-type GaN layer including the above-described p-type GaN layer 22 that functions as a low-resistance layer generally needs to have a relatively large thickness for reasons such as formation of an electrode. During the growth, if so-called dislocations occur, which drag lattice defects of the underlying crystal structure,
This not only affects the clad layer laminated thereon, but also has a significant influence on the quality of the light emitting device, such as insufficient carrier injection into the clad layer.

Therefore, in the GaN-based light emitting device according to the first embodiment, an SiO ₂ mask for forming a plurality of openings is formed on the p-type GaN layer 22 (step S103), and the openings are formed. A second p-type GaN layer is regrown thereon (step S104).

The SiO ₂ mask 23 is formed by the silicon substrate 20, the p-type GaN buffer layer 21 and the first
The stacked substrate composed of the p-type GaN layer 22 is moved from the growth chamber to the patterning chamber, and is formed in the patterning chamber by a photolithography technique and an etching process (FIG. 3C).

When the formation of the SiO ₂ mask is completed, the Si 2
The laminated substrate on which O ₂ is formed is moved from the patterning chamber to the growth chamber, and again in the growth chamber, the second p-type G
aN layer is grown. This second p-type GaN layer 24
NH _{3 at a} vapor pressure of 5 × 10 ^-6 Torr and a vapor pressure of 5 × 10 ^-7
Using a molecular beam of Ga and Mg of Torr, Mg is applied to the p-type GaN layer 22 and the SiO ₂ mask 23.
Is obtained as a 50 μm-thick GaN layer (FIG. 3D).

As described above, by providing an opening and partially regrowing the p-type GaN layer, the influence of lattice defects of the underlying first p-type GaN layer 22 can be reduced. It is possible to reduce the occurrence of dislocations.

Next, a p-type AlGaN layer functioning as a cladding layer is formed (step S105). This p
The AlGaN layer 25 is formed of ammonia (NH ₃ ) having a vapor pressure of 5 × 10 ⁻⁶ Torr and G of a vapor pressure of 5 × 10 ⁻⁷ Torr.
Using each molecular beam of a and Al at a vapor pressure of 1 × 10 ⁻⁷ Torr, a 1000 ° -thick AlGaN layer doped with Mg is obtained on the p-type GaN layer 24 (FIG. 3 (e). )).

Then, a GaN / GaP multilayer film to be an active layer is formed on the p-type AlGaN layer 25 (Step S106). FIG. 4 is a flowchart showing a procedure for forming the GaN / GaP multilayer film. FIG.
FIG. 5 is a sectional view for explaining a GaN / GaP multilayer film formed according to the flowchart shown in FIG.

The GaN / GaP multilayer film includes a GaP layer and a GaP layer.
Characterized by a structure in which N layers are alternately stacked
I have. Therefore, first, on the p-type AlGaN layer 25 described above,
Next, a GaP layer is formed (step S121). This G
The aP layer 31 has a vapor pressure of 5 × 10 ^-7Torr Ga and steam
Atmospheric pressure 5 × 10^-6Torr's tertiary butyl phosphite
Using each molecular beam with a Ga
It is obtained as a P layer (FIG. 5 (f)).

Subsequently, on this GaP layer 31, GaN
A layer is formed (Step S122). This GaN layer 32
Is ammonia (NH ₃ ) with a vapor pressure of 5 × 10 ⁻⁶ Torr
And a GaP layer having a thickness of about 10 molecules using each molecular beam of Ga and a vapor pressure of 5 × 10 ⁻⁷ Torr (FIG. 5G).

The GaP layer 31 and the GaN layer 32
Is repeated five times (step S1).
23), a GaN / GaP multilayer film 30 in which a GaP layer 31 and a GaN layer 32 are alternately stacked a plurality of times is obtained (FIG. 5).
(H)).

When the formation of the GaN / GaP multilayer film 30 is completed, an n-type AlGaN layer functioning as another clad layer is formed (step S107).
This n-type AlGaN layer 26 has a vapor pressure of 5 × 10 ⁻⁶ Torr.
and NH ₃ in r, and Ga vapor pressure 5 × 10 ^-7 Torr, and Al vapor pressure 1 × 10 ^-7 Torr, the vapor pressure 1 × 10 ^-8 T
Using each molecular beam with orr Si, the GaN /
On the GaP multilayer film 30, a thickness 100 doped with Si
It is obtained as a 0 ° AlGaN layer (FIG. 6 (i)).

Finally, an n-type GaN layer is formed (step S108). The n-type GaN layer 27 is composed of NH ₃ having a vapor pressure of 5 × 10 ⁻⁵ Torr and a vapor pressure of 5 × 10 ⁻⁷ T.
Using a molecular beam of Ga at orr and Si at a vapor pressure of 1 × 10 ⁻⁸ Torr, a 1000 ° thick GaN layer doped with Si is obtained on the n-type AlGaN layer 26 (FIG. 6). (J)).

When a single layered film constituting the GaN-based light emitting device is formed, the GaN / G
In the aP multilayer film 30, a heat treatment for generating a mixed crystal of GaNP is performed (step S109). This heat treatment is performed by heating the substrate at 950 ° C. for 30 minutes.

By this heat treatment, thermal energy can be given to P in the GaN / GaP multilayer film 30, and the mixed crystal of P and GaN is realized. This is Ga, P
When a thin film is to be grown directly by molecular beams of H ₃ and NH ₃ , the formation of GaNP cannot be expected due to the difficulty of migration of P.
By forming a GaP multilayer film 30 ', the GaNP30
Is realized (FIG. 6 (k)).

That is, since GaN and GaP can be formed stably as independent thin films, a multilayer film in which P is confined as GaP between the GaN layers is once formed, , GaP can be decomposed, and a mixed crystal of the decomposed P and the adjacent GaN layer can be achieved.

In particular, since the thickness of the GaP layer is sufficiently smaller than the thickness of the GaN layer, G
Decomposition and extraction of P in the aP layer are facilitated, and the promotion of mixed crystal of GaN and P is promoted.

When the mixed crystal formation of the GaNP 30 is completed in this way, an electrode is formed on the laminated film (Step S).
110). FIG. 7 is a cross-sectional view of a GaN-based light emitting device for explaining electrode formation. As shown in FIG. 4, this electrode preparation first moves the laminated substrate to the patterning chamber,
The silicon substrate 20, the p-type GaN buffer layer 21, the first p-type GaN layer 22, and a part of the second p-type GaN layer 24 (thickness where the SiO ₂ mask 23 is formed) are removed by etching. (FIG. 6 (l)).

Subsequently, the exposed p-type GaN layer 24 and n
After depositing a patterning mask such as SiO _{2 on} each surface of the type GaN layer 27 using a plasma CVD apparatus,
As shown in FIG. 7 (m), the n-type electrode 11 and the p-type
Are respectively formed.

The surface of the n-type GaN layer 27 has Ti /
The n-type electrode 11 is formed by depositing a metal such as Al / Au, and the p-type electrode 12 is formed by depositing a metal such as Au / Ni on the surface of the p-type GaN layer 24.

When a voltage was applied to the GaN-based light-emitting device manufactured in this manner and light emission was examined, an applied voltage of 4 V
, An extremely strong emission peak was observed at a band edge of 380 nm. Other peaks were not observed. That is, it was confirmed that a high-intensity ultraviolet LED was produced.

As described above, according to the GaN-based light-emitting device of the first embodiment, when the GaN-based light-emitting device is manufactured according to the gas source MBE method, GaP layers and GaN layers are alternately stacked. The active layer as the active layer,
By subjecting this to a heat treatment, GaNP is mixed, so that it is difficult to mix P by adding P in the gas phase.
aNP can be obtained with sufficiently high luminous efficiency and the like.

Further, a p-type GaN layer of a low resistance layer, which is positioned lower in the stacking order, is provided with a relatively thin first GaN layer and a mask such as SiO ₂ on the first GaN layer. Since it is composed of the second GaN layer partially regrown through the plurality of openings, the occurrence of dislocations can be reduced, and as a result, deterioration of the light emitting element can be prevented. Can be.

In the above-described example, the active layer is made of
In the case of GaNAs, a GaN / GaAs multilayer film is formed in the same manner, and mixed crystal formation of GaNAs can be achieved by a subsequent heat treatment.

Embodiment 2 Next, a GaN-based light emitting device according to the second embodiment and a method for forming the same will be described. Embodiment 2 is different from Embodiment 1 in that the gas source MB is used.
While a GaN-based light-emitting device was fabricated using the E method,
A GaN-based light-emitting element having the same configuration is formed using an OCVD method. The structure of the finally obtained GaN-based light-emitting device is the same as that shown in FIG. 1, and the description is omitted here.

FIG. 8 is a flowchart showing a procedure for manufacturing a GaN-based light emitting device according to the second embodiment. MOC
In the VD method, first, a crystal substrate such as a silicon substrate is placed on a susceptor in a growth chamber. Then, in this state, the temperature of the silicon substrate is maintained at 640 ° C., and the p-type G
The formation of the aN buffer layer is started (Step S20)
1).

This p-type GaN buffer layer has a thickness of 200 sc
cm dimethylhydrazine (DMH) and 20 sc
By supplying TMG of about cm and cyclopentadienyl magnesium (CpMg) of about 3 sccm, a crystal structure having a thickness of 50 ° is formed on the silicon substrate.

Subsequently, the substrate temperature is maintained at 850 ° C.
Form a first p-type GaN layer (Step S20)
2). The first p-type GaN layer includes TMG of about 20 sccm, NH _{3 of} about 1500 sccm, and ₃ sccc.
m of biscyclopentadienyl magnesium (bC
pMg) is grown on the p-type GaN buffer layer described above, and Mg-doped G
Obtained as an aN layer.

Next, multiple layers are formed on the n-type GaN layer 22 described above.
SiO for forming a number of openings _TwoForm a mask
(Step S203) A second p-type Ga is formed on the opening.
The N layer is grown again (step S204). Note that Si
O_TwoRegarding mask creation and its effects,
Since it is the same as in the first embodiment, the description is omitted here.

This second p-type GaN layer has a thickness of 20 sccm.
About TMG, about 1500 sccm NH ₃ ,
The raw material gas of bCpMg of about sccm
Grown on a p-type GaN layer and a SiO ₂ mask,
g is obtained as a doped GaN layer with a thickness of 50 μm.

Next, a p-type AlGaN layer functioning as a cladding layer is formed (step S205). This p
The type AlGaN layer has a TMG of about 20 sccm,
About 00 sccm of NH ₃ , about ₃ sccm of cyclopentadienyl magnesium (CpMg), and 5 scc
A raw material gas of TMA of about m is grown on the p-type GaN layer, and Mg-doped Al
Obtained as a GaN layer.

Then, a GaN / GaP multilayer film to be an active layer is formed on this p-type AlGaN layer (step S).
206). The GaN / GaP multilayer film is first formed by the above-mentioned p
A GaP layer is formed on the p-type AlGaN layer, and then a GaN layer is formed thereon.
It is obtained by repeatedly forming a set composed of the aN layer about five times.

In this case, the GaP layer has a thickness of 20 scc.
m of TMG and about 500 sccm of phosphine (PH ₃ ) source gas of GaP having a thickness of about 1 to 2 molecules.
Obtained by growing as a layer. The GaN layer has a thickness of 20
TMG of about sccm and NH of about 1500 sccm
It is obtained by growing the source gas of No. ₃ as a GaN layer having a thickness of about 10 molecules.

When the formation of the GaN / GaP multilayer film is completed, n
A mold AlGaN layer is formed (step S207). This n-type AlGaN layer has a TMG of about 20 sccm,
About 1500 sccm NH ₃ and about 2 sccm S
iH ₄ and a source gas of TMA of about 5 sccm are grown on the above-mentioned GaN / GaP multilayer film to obtain an AlGaN layer doped with Si and having a thickness of 1000 °.

Finally, an n-type GaN layer is formed (Step S208). This n-type GaN layer has a thickness of 20 sc
cm of TMG and 1500 sccm of NH
A SiH ₄ source gas of about ₃ and 2 sccm is grown on the n-type AlGaN layer to obtain a Si-doped GaN layer having a thickness of 1000 °.

Then, once the laminated film constituting the GaN-based light emitting device is formed, the GaN / G
In the aP multilayer film, a heat treatment for generating a mixed crystal of GaNP is performed (step S209). This heat treatment is performed by heating the substrate at 950 ° C. for 30 minutes. By this heat treatment, a mixed crystal of P and GaN is realized, and GaNP is generated.

When the mixed crystal of the GaNP is completed in this way, an electrode is formed on the laminated film (step S21).
0). Since the formation of the electrodes is the same as that of the first embodiment, the description is omitted here.

As described above, according to the GaN-based light-emitting device according to the second embodiment, the same effect as that of the first embodiment can be obtained when the GaN-based light-emitting device is manufactured according to the MOCVD method. Can be enjoyed.

In addition to the vapor phase growth methods shown in Embodiments 1 and 2, a chloride type vapor phase growth using a chloride such as gallium chloride or a halide type vapor phase growth using a hydride as a raw material can be used. A GaN-based light emitting device according to the present invention can also be produced.

Further, in the first and second embodiments described above, the active layer is described by taking as an example the mixed crystal of GaNP or GaNAs. However, other active layers such as GaAsP / GaN may be used.
It goes without saying that the present invention can be applied to a case where a multilayer film is formed by a combination of aN multicomponent compound semiconductors.

Further, in Embodiments 1 and 2 described above, a light emitting element having a double hetero structure is described as an example. However, the present invention is not limited to this. The present invention can be similarly applied to a device having a single hetero junction, a device having a pn junction, or a device having one or a plurality of quantum well structures, and the same effects can be obtained.

[0084]

As described above, according to the first aspect of the present invention, the state after heat treatment is performed on a multilayer film formed by laminating a GaN layer and a GaP layer is defined as an active layer. Since it is a functioning GANP layer, it is possible to obtain the effect of obtaining the original light emission characteristics of a GaNP layer to which a sufficiently large amount of P is added.

According to the second aspect of the present invention, G
The state after heat treatment is performed on the multilayer film formed by laminating the aN layer and the GaAs layer is referred to as a GaNAs layer functioning as an active layer. There is an effect that characteristics can be obtained.

According to the third aspect of the present invention, G
Since the GaNASP layer functioning as the active layer is formed after the heat treatment is performed on the multilayer film formed by laminating the aN layer and the GaASP layer, the GaNASP layer to which enough AS and P are added originally It is possible to obtain the effect that the light emission characteristics can be obtained.

According to the fourth aspect of the present invention, G
Since the Ga mixed crystal layer of aP or the like is formed extremely thin, the decomposition of the Ga mixed crystal layer is promoted when heat treatment is performed, and the group V atoms contained therein are diffused. This has the effect that it can be performed.

According to the fifth aspect of the present invention, the low-resistance layer formed on the buffer layer is formed by the first low-resistance layer serving as a base and the second low-resistance layer selectively grown by using a mask. Since the second low-resistance layer is composed of the second low-resistance layer, the second low-resistance layer is used as a low-resistance layer for providing an electrode. There is an effect that a GaN-based light emitting device having more preferable characteristics can be obtained.

Further, according to the invention of claim 6, since the second low-resistance layer is thicker than the first low-resistance layer, more high-quality low-resistance layers can be obtained. To play.

[Brief description of the drawings]

FIG. 1 is a sectional view of a GaN-based light emitting device according to a first embodiment.

FIG. 2 is a flowchart illustrating a procedure for manufacturing the GaN-based light emitting device according to the first embodiment.

FIG. 3 is a cross-sectional view for explaining a GaN-based light-emitting device manufactured according to the method for manufacturing a GaN-based light-emitting device according to the first embodiment.

FIG. 4 is a flowchart showing a procedure for forming a GaN / GaP multilayer film in the GaN-based light emitting device according to the first exemplary embodiment;

FIG. 5 is a cross-sectional view illustrating a GaN / GaP multilayer film formed according to the method of manufacturing a GaN-based light emitting device according to the first embodiment.

FIG. 6 is a cross-sectional view for explaining a GaN-based light-emitting device manufactured according to the method for manufacturing a GaN-based light-emitting device according to the first embodiment.

FIG. 7 is a cross-sectional view of the GaN-based light emitting device according to the first embodiment, illustrating the formation of an electrode.

FIG. 8 is a flowchart showing a procedure for manufacturing a GaN-based light emitting device according to the second embodiment.

[Explanation of symbols]

Reference Signs List 11 n-type electrode 12 p-type electrode 20 silicon substrate 21 buffer layer 22, 24 p-type GaN layer 23 SiO ₂ mask 25 p-type AlGaN layer 26 n-type AlGaN layer 27 n-type GaN layer 30 GaP / GaN multilayer film 30 ′ GaNP layer 31 GaN layer 32 GaP layer

Claims (6)

[Claims] 1. A mixed crystal obtained by performing a heat treatment on a multilayer film in which GaN layers and GaP layers are alternately stacked.
G having a structure in which an aNP layer is an active layer.
aN-based light-emitting element. 2. A GaN-based light-emitting device characterized in that a GaN-based light-emitting element has a structure in which a mixed GaN layer is formed by performing heat treatment on a multilayer film in which GaN layers and GaAs layers are alternately stacked. . 3. A GaN-based light emitting device having a structure in which a GaAsP layer mixed and mixed by performing a heat treatment on a multilayer film in which GaN layers and GaAsP layers are alternately stacked is used as an active layer. . 4. The G according to claim 1, wherein the GaN layer is larger than a thickness of another Ga mixed crystal layer constituting the multilayer film together with the GaN layer.
aN-based light-emitting element. 5. A method for producing a GaN-based light-emitting device in which a GaN-based light-emitting device is formed as a laminated structure of thin films by a vapor deposition method, wherein a first low-resistance layer is formed on a buffer layer formed on a thin-film formation substrate. Forming; forming a mask for forming at least one opening on the first low resistance layer; and forming a second low resistance on the first low resistance layer and the mask. Forming a layer; and forming a clad layer on the second low-resistance layer. 6. The Ga according to claim 5, wherein the second low resistance layer is thicker than the first low resistance layer.
Method for producing N-based light emitting element.