JP3065780B2 - Gallium nitride based light emitting device and manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gallium nitride based semiconductor light emitting device which can be used for a light emitting diode in the ultraviolet region to the visible region and a laser diode which are most suitable for a light source of a display, an optical communication device and an OA device. It relates to a manufacturing method.

[0002]

2. Description of the Related Art Semiconductor devices are used as display devices and various light sources in a wide variety of fields. However, the ultraviolet region ~
Blue light-emitting diodes have not been put to practical use, and development for displays requiring three primary colors is urgently required. Although a laser diode is expected as a light source for an optical disk or a compact disk to increase the recording density ten times or more, it has not been put to practical use yet. GaN, ZnSe, ZnS are used as the ultraviolet to blue light emitting diode and the laser diode.
It has been considered to use a compound semiconductor such as SiC or SiC.

[0003] Gallium nitride (GaN) is mostly formed on a sapphire C-plane by MOCVD or VPE [Journal of Applied Physics].
sics) 56 (1984) 2367-2368].
However, it is necessary to raise the reaction temperature, which is not only difficult to manufacture, but also due to the lack of nitrogen, the carrier density becomes extremely large, and good semiconductor characteristics cannot be obtained. To overcome this, a buffer layer of aluminum nitride is provided on the sapphire C surface, and a GaN thin film having a relatively large thickness is formed thereon to manufacture a semiconductor light emitting device.

Further, in order to realize low-temperature film formation, there is an attempt to activate a nitrogen source by an electron shower [Japanese Journal of Applied Physics].
(Jap. J. Appl. Phys.), 20, L54.
5 (1981)], this method is said to be insufficient for improving the film quality. Further, it has been considered to form a film using a highly active nitrogen source so as not to cause a shortage of nitrogen. As nitrogen sources having high activity, there are atomic nitrogen and nitrogen ions, but a film forming technique by a gas source MBE method using a conventional plasma [Journal of Vacuum Science and Technology]
(J. Vac. Sci. Technol.), A7,7
01 (1989)], it is difficult to control the carrier density, and at present, it is impossible to produce a semiconductor thin film having good characteristics.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and to provide a light emitting device structure having good characteristics as a semiconductor light emitting device and a method of manufacturing the same.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, a gallium nitride based semiconductor thin film formed on a specific sapphire crystal plane in a high vacuum is used for a light emitting element. It has been found that a thin film has good optical and electrical characteristics, and a semiconductor light emitting device having excellent characteristics can be obtained.

That is, the present invention provides an n ⁺ -type gallium nitride-based semiconductor directly formed on a substrate surface which is 9.2 degrees rotated from the sapphire R surface by projecting the R plane of the sapphire c-axis as a rotation axis. A n-type single-crystal gallium nitride-based semiconductor layer and at least one light-emitting layer including a p-type or i-type single-crystal gallium nitride-based semiconductor layer, and applying a voltage to the light-emitting layer. A gallium nitride-based semiconductor light-emitting device comprising an electrode at a desired site, and a gas source for supplying a gaseous compound containing nitrogen in the MBE method;
Using a crystal growth apparatus having a solid source for supplying a group III element, a nitrogen-containing gaseous state is used as a substrate surface, which is a 9.2-degree rotation from the sapphire R-plane by using the R-plane projection of the sapphire c-axis as a rotation axis. Forming an n ⁺ -type gallium nitride-based semiconductor layer on a substrate by supplying a compound, a group III element and an n-type dopant; supplying a nitrogen-containing gaseous compound and a group III element to an n-type single crystal nitride Forming a gallium-based semiconductor layer, supplying a gaseous compound containing nitrogen, a group III element and a p-type dopant to form
A method for manufacturing a semiconductor light emitting device, comprising at least a step of forming a single-crystal or i-type single-crystal gallium nitride-based semiconductor layer.

Hereinafter, the present invention will be described in more detail. The sapphire R plane in the present invention refers to [1, -1,0,2] in single crystal sapphire (α-Al ₂ O ₃ ).
Plane (R-plane) surface. The R-plane projection of the sapphire c-axis is sapphire single crystal (corundum type hexagonal).
This is the projection of the c-axis of the unit vector in the unit cell onto the R plane (FIG. 1).

The reference plane in the present invention is a plane which is 9.2 degrees rotated from the sapphire R plane by using the R plane projection of the sapphire c-axis as a rotation axis (FIG. 2). This 9.
It is preferable that the off angle from the 2 degree off plane be ± 2 degrees or less in order to obtain a gallium nitride thin film having good crystallinity. By using this substrate surface, the lattice mismatch between the sapphire substrate and the gallium nitride based semiconductor thin film can be reduced, and the initial growth (less than 100 Å)
In this case, a gallium nitride-based thin film with good single crystal properties, which has a flat surface and can observe streaks of a diffraction pattern in RHEED measurement, can be obtained. The mismatch of the lattice constant is 5% or less, preferably 2% or less.

In the present invention, a single-crystal gallium nitride-based semiconductor thin film is formed on the surface of a substrate rotated 9.2 degrees with the R-plane projection of the sapphire c-axis from the R-plane of sapphire as a rotation axis. Since the semiconductor crystal is lattice-matched, it is possible to obtain a gallium nitride-based semiconductor thin film having an extremely thin film thickness, good single crystallinity, and excellent optical and electrical characteristics. In this case, a dry etching method can be used, and light extraction efficiency can be increased. The thickness of the entire gallium nitride based semiconductor light emitting device is preferably 3 μm or less, more preferably 2 μm.
Is preferably not more than 1 μm,
It becomes more preferable.

In the present invention, n⁺Gallium nitride semiconductor
The body layer is made of a gallium nitride based semiconductor layer made of Si, Ge, C, S
doping n-type dopants such as n, S, Se, Te, etc.
Semiconductor layer having a carrier density of 5 × 10¹⁸/ Cm^Three
Above, preferably 10¹⁹/ Cm ^ThreeThat is all. n⁺Type
The light emission of the device can be achieved by using a gallium arsenide based semiconductor layer.
To lower the applied voltage for
Efficient and uniform current injection into the light-emitting layer due to the anti-layer
To increase the emission intensity and improve the uniformity of the emission distribution.
Can be. And n⁺Gallium nitride based semiconductor layer
An electrode provided between the light layer and the light emitting layer to apply a voltage
It can be. From single crystal gallium nitride based semiconductor
Light emitting layer is a single bond of n-type, p-type or i-type
Gallium nitride based semiconductor, for example, n / i /
p, n / p, n / i, n / p / p⁺Has a structure like
In addition, each layer is composed of a single crystal gallium nitride
It is also possible to use an aluminum-based semiconductor thin film. Also, simply
Formation of quantum well structure composed of crystalline gallium nitride based semiconductor
At the very least, it is necessary to increase the luminous efficiency or control the luminous wavelength.
Both are possible.

[0012] The single crystal gallium nitride based semiconductor referred to in the present invention
The layer refers to Ga alone or Ga mainly as Al or
From at least one group III element selected from In
Is a compound. Changing the composition of the compound
Thus, the emission color can be changed. Light emitting device structure
Are examples of n shown in FIG.⁺-GaN (Si) / n-
GaN / i-GaN (Mg), n shown in FIG.⁺-Ga
_1-xIn_xN / n-Ga_1-xIn_xN / i-Ga_1-xI
n_xN, n shown in FIG.⁺-Al_1-xGa_xN / n-Al
_1-xGa_xN / i-Al_1-xGa_xN, n shown in FIG.
⁺-GaN / n-GaN / i-GaN or n shown in FIG.
⁺-GaN / n-Ga_1-xIn_xN / p-Ga_1-yIn
_yN (x ≧ y), FIG. 12 shows two types of light emission having different emission colors.
A light emitting layer between the light emitting layers.⁺Gallium nitride based semiconductor
This is an example of a structure in which layers are stacked, and n ⁺-GaN / n-GaN
/ P-GaN / n⁺-GaN / n-Ga_1-xIn_xN /
p-Ga_1-xIn_x3 shows a laminated structure of N. For example, electrodes
When a voltage is applied between the electrode 8 (a) and the electrode 8 (b), blue light is emitted.
Light is applied between the electrode 8 (c) and the electrode 8 (d).
Then, green light is emitted, and the electrodes 8 (a) and 8 (b) and
Simultaneous application of voltage between electrode 8 (c) and electrode 8 (d)
Then, yellow light emission can be obtained. Like this
By choosing the electrode to apply, two different emission
A light-emitting element that emits light of a color or a neutral color can be obtained.
You.

FIG.⁺-GaN / n-Ga_1-xIn
_xN / n-Ga_1-yIn_yN / p-Ga_1-xIn_xN
(X ≧ y) is an example of a laminated structure.⁺-GaN /
n-GaN / p-GaN, n⁺-GaN / n-Ga_1-x
In_xN / p-Ga_1-xIn _xN, n⁺-Ga_1-xAl
_xN / n-Ga_1-xAl_xN / p-Ga_1-xAl_xN,
n⁺-Ga_1-xAl_xN / n-Ga_1-xAl_xN / p-
Ga_1-yAl_yN (x ≧ y), n⁺-GaN / n-Ga
N / n-Ga_1-xIn_xN / p-Ga_1-xIn _xN,
n⁺-GaN / n-GaN / n-Al_1-yGa_yN / p
-Al_1-xGa _xN (x ≧ y), n⁺-GaN / n-G
aN / n-Ga_1-xIn_xN / p-Ga _1-xIn_xN,
n⁺-Al_1-xGa_xN / n-Al_1-xGa_xN / n-
Al_1-yGa_yN / p-Al_1-xGa_xN (x ≧ y),
n⁺-GaN / n-Ga_1-aIn _aN / p-Ga_1-bI
n_bN / n-Al_1-xGa_xN / n-Al_1-yGa_yN
/ P-Al_1-xGa_xN (x ≧ y, a ≧ b), n⁺-G
aN / n-GaN / n-Ga_1-xIn_xN / p-Ga
_1-xIn_xN, n⁺-GaN / n-GaN / p-GaN
/ N-Ga_1-xIn_xN / p-Ga_1-xIn_xN, n⁺
-Ga_1-xIn_xN / n-Ga_1-xIn_xN / n-Ga
_1-yIn_yN / p-Ga_1-xIn_xN (x ≧ y), n⁺
-GaN / n-GaN / n-Al_1-yGa_yN / p-
Al_1-xGa_xN (x ≧ y), n⁺-GaN / n-Ga
N / n-Ga_1-xIn_xN / p-Ga_1-xIn_xN, n
⁺-Al_1-xGa_xN / n-Al_1-xGa_xN / n-A
l _1-yGa_yN / p-Al_1-xGa_xN (x ≧ y), n
⁺-Ga_1-aIn_aN / n-Ga_1-aIn_aN / p-G
a_1-bIn_bN / n-Al_1-xGa_xN / n-Al _1-y
Ga_yN / p-Al_1-xGa_xN (x ≧ y, a ≧ b)
is there. However, it is not limited to these.
In addition, using various combinations of the above structures,
Light-colored elements and multi-coloring can also be performed.

As an electrode for injecting current, A
1, In, Au, Al-In, Al-Sn, In-Sn
Metal, tin oxide, indium oxide, tin oxide-indium oxide, zinc oxide, degenerated GaN, ZnSe, or the like can be used. An electrode for applying a voltage to the light emitting layer is formed at a desired portion to emit light. A device is manufactured. further,
It is more preferable to alloy or laminate a metal such as Ni on these electrodes to improve the heat resistance of the electrodes.

Next, a method for manufacturing the gallium nitride based semiconductor light emitting device of the present invention will be described. As the gaseous compound used in the present invention, ammonia, nitrogen trifluoride, hydrazine or dimethylhydrazine can be used alone or a mixed gas mainly containing them. Also,
Ammonia, nitrogen trifluoride, hydrazine or dimethylhydrazine can be used after dilution with an inert gas such as nitrogen, argon or helium. As a method for supplying these gases, a valve, a flow rate control device, and a pressure control device are connected in the middle of the pipe to the cell to control the mixing ratio and supply amount of these gases, and to start and stop the supply. It is preferable to use a material which can be used. A gas cell can be used to supply these gases to the substrate surface, and the gas cell is heated to a predetermined temperature to heat a compound containing nitrogen to produce a high-quality gallium nitride-based semiconductor thin film. It is more preferable to supply it to the surface of the substrate. The gas cell is filled with a material having excellent corrosion resistance such as alumina, silica, boron nitride, silicon carbide, etc. in a fibrous, flake, crushed, or granular form in order to efficiently heat the gas cell. Alternatively, it is preferable to increase the heating efficiency by making them porous and setting them in the gas cell to increase the contact area with the gaseous compound. It is also possible to activate nitrogen using a plasma gas cell and supply it to the substrate surface. The supply amount of the gaseous compound to the substrate surface needs to be larger than that of the solid source. When the supply amount of the gaseous compound is smaller than the supply amount of the solid source, the gaseous compound is supplied from the gaseous compound from the gallium nitride-based semiconductor thin film. This makes it difficult to obtain a good gallium nitride-based semiconductor thin film. Therefore, the supply amount of the gaseous compound should be at least 10 times, preferably at least 100 times, more preferably at least 1000 times that of the solid source.

In the solid source of the present invention, a simple substance, an alloy, or a metal salt of a group III element metal can be used as the group III element. Group III elements include Al and G
It is at least one kind of element selected from a and In. Further, when the gallium nitride based semiconductor thin film of the present invention is manufactured, impurities can be doped to control the carrier density and control the p-type, i-type, n-type or n ⁺ -type conductivity. Examples of impurities to be doped to obtain a p-type or i-type gallium nitride based semiconductor thin film include Mg, Ca, Sr, Zn, Be, Cd, Hg and Li, and n-type or n ⁺ -type gallium nitride based thin films. As impurities to be doped to obtain a semiconductor thin film, Si, Ge,
C, Sn, S, Se, Te, and the like. By changing the type and doping amount of these dopants, the type of carrier and the carrier density can be changed. In this case, the doping concentration may be changed depending on the direction of the film thickness, or a δ-doping method for doping only a specific layer may be used.

In preparing the gallium nitride based semiconductor thin film by the MBE method according to the present invention, a compound containing a group III element and nitrogen is simultaneously supplied to the substrate surface, or a compound containing a group III element and nitrogen is alternately supplied. It is also possible to carry out a method of supplying to the substrate surface or interrupting the growth during the growth of the thin film to promote crystallization of the thin film. In particular,
It is preferable that the film is grown while observing the RHEED pattern and confirming that streaks are visible.

Hereinafter, MB using ammonia as an example will be described.
A method for manufacturing a gallium nitride-based semiconductor light emitting device having a gallium nitride-based semiconductor laminated structure using the E method will be described, but is not particularly limited thereto. As a device, crucibles for evaporation (knudsen cells) 22, 23, 24 and 25 are placed in a vacuum vessel 21 as shown in FIG.
A gas source MBE device equipped with a gas cell 28 and a substrate heating holder 27 was used.

Ga metal was put into the evaporating crucible 22 and heated to a temperature of 10 ¹³ to 10 ¹⁹ / cm ² · sec on the substrate surface. A gas cell 26 was used to introduce ammonia, and the ammonia was directly sprayed onto the substrate 28. The introduction amount was supplied so as to be 10 ¹⁶ to 10 ²⁰ / cm ² · sec on the substrate surface. Evaporation crucibles 23, 24, and 25 contain In, Al, and the like for producing a mixed crystal compound semiconductor.
As, Sb, etc. and dopants such as Mg, Ca, Sr, Z
n, Be, Sb, Si, Ge, C, Sn, Hg, Li,
P and the like are added, and the temperature and the supply time are controlled so as to reach a predetermined supply amount.

The substrate 26 was heated from 200 ° C. to 900 ° C. using a surface rotated 9.2 ° from the R surface of the sapphire c-axis using the R-plane projection of the sapphire c-axis as a rotation axis. First, after heating the substrate 28 at 900 ° C. for 30 minutes, the substrate 28 is set at a predetermined growth temperature and doped with an n-type dopant at a film formation rate of 0.1 to 10 Å / sec to form a substrate of 0.05 to 2 μm.
An n ⁺ -type gallium nitride-based semiconductor layer having a thickness of m was produced.
Subsequently, a film thickness of 0.05 is formed on the gallium nitride based semiconductor layer.
An undoped gallium nitride-based semiconductor thin film of about 1 μm was produced. Further, the gallium nitride-based semiconductor layer doped with Mg of 0.01 to 1 μm was formed by opening the Mg shutter at the same time as the Ga shutter, thereby producing a gallium nitride-based semiconductor laminated structure. RHEE after film formation shown in FIG.
The streak-like D-diffraction pattern indicates that the laminated thin film is flat and has good crystallinity.

Next, by performing a lithography process on the laminated thin film, an electrode for setting an element shape and injecting a current is provided. The lithography process can be performed by a process using a usual photoresist material, and a dry etching method can be performed as an etching method. As a dry etching method, an ordinary method can be used, and ion milling,
ECR etching, reactive ion etching, ion beam assisted etching, and focused ion beam etching can be used. Particularly, in the present invention, one of the features is that these dry etching methods can be applied efficiently because the total thickness of the gallium nitride based semiconductor laminated thin film is small. As an electrode for injecting current, A
1, In, Au, Al-In, Al-Sn, In-Sn
Metal, tin oxide, indium oxide, tin oxide-indium oxide, zinc oxide, degenerated GaN, ZnSe, or the like can be used, and can be manufactured by MBE, vacuum evaporation, electron beam evaporation, sputtering, or the like. Can be.

The element obtained by this method is cut by a dicing saw or the like, and wiring is performed using a gold wire by a wire bonder to produce a product.

[0023]

The present invention will be described in more detail with reference to the following examples.

[0024]

Embodiment 1 A description will be given of an example in which a gallium nitride based semiconductor light emitting device is manufactured by the MBE method using ammonia. A crystal growth apparatus including an evaporation crucible 22, 23, 24, and 25, a gas cell 26, and a substrate heating holder 28 in a vacuum vessel 21 as shown in FIG. 3 was used. Ga metal was put into the evaporating crucible 22 and heated to 1020 ° C., and Mg and Si were put into the evaporating crucibles 24 and 25 and heated to 280 ° C. and 1200 ° C., respectively. Ammonia is used as a gas, and a gas cell 26 filled with alumina fibers is used for gas introduction. The gas is heated at 370 ° C. and supplied at a rate of 5 cc / min by directly blowing the gas onto the substrate 28. did.

As the substrate 28, from the sapphire R surface,
A sapphire substrate having a substrate surface rotated 9.2 degrees using the R-plane projection of the sapphire c-axis as a rotation axis was used. The pressure in the vacuum vessel was 2 × 10 ⁻⁶ Torr during film formation. First, the substrate 28 is heated at 900 ° C. for 30 minutes, and then the film is formed while maintaining the temperature at 750 ° C. The film is formed by simultaneously opening the crucible shutters of Ga and Si while supplying ammonia from the gas cell 28, and setting the Ga beam intensity to 5.51 × 10 ¹⁴ / cm ² · sec.
0.3 μm thickness at 0 Å / sec deposition rate
An n ⁺ -type GaN thin film doped with m Si is prepared.
Subsequently, only the shutter of the Ga crucible was opened,
A 2 μm undoped n-type GaN thin film is prepared. Further, a Ga shutter and a Mg crucible shutter were simultaneously opened on these stacked structures to form an i-type doping layer having a thickness of 0.05 μm, thereby producing a gallium nitride based semiconductor stacked structure. The RHEED diffraction pattern after film formation shown in FIG. 4 shows a streak shape, which indicates that the laminated thin film is flat and has good crystallinity.

Next, an electrode for injecting a current is provided by performing a lithography process on the laminated thin film. The lithography process can be performed by a process using a normal photoresist material. As an etching method, a window for forming an electrode into which current is injected is formed by performing ion milling. Then, Al
The electrodes were formed by a vacuum deposition method.

The device obtained by this method was cut with a dicing saw, and wiring was performed using a gold wire with a wire bonder. FIG. 5 shows the device structure of the present invention, and FIG. 6 shows the results of measuring the diode characteristics. When a voltage of 15 V was applied to the electrode of this element and a current of 30 mA was injected, blue light emission of 70 mcd was observed. The emission spectrum is shown in FIG.

[0028]

[Embodiment 2] Ga by the MBE method using ammonia
_{An example in which a 1-x} In _x N-based semiconductor light emitting device is manufactured will be described. A gas source MBE including an evaporation crucible 22, 23, 24, and 25, a gas cell 26, and a substrate heating holder 27 in a vacuum vessel 21 as shown in FIG. 3 was used.

Ga metal is put into the evaporating crucible 22.
The mixture was heated to 020 ° C., the In crucible 23 was charged with In metal and heated to 950 ° C., and the crucibles 24 and 25 were charged with Mg and Si and heated to 280 ° C. and 1200 ° C., respectively. Ammonia is used as a gas, and a gas cell 26 filled with alumina fibers is used for gas introduction. The gas is heated at 370 ° C. and supplied at a rate of 5 cc / min by directly blowing the gas onto the substrate 28. did.

As the substrate 28, from the sapphire R surface,
A sapphire substrate having a substrate surface rotated 9.2 degrees using the R-plane projection of the sapphire c-axis as a rotation axis was used. The pressure in the vacuum vessel was 2 × 10 ⁻⁶ Torr during film formation. First, the substrate 28 is heated at 900 ° C. for 30 minutes, and then the film is formed while maintaining the temperature at 750 ° C. The film is formed by supplying Ga, In and Si while supplying ammonia from the gas cell 26.
The shutter of the crucible was simultaneously opened, and the film was formed at a film thickness of 0.3 μm at a film forming speed of 1.2 angstroms / sec.
n ⁺ -type Ga _{1 -x} In _x N doped with i (X = 0.1
2) Prepare a thin film. Subsequently, the shutter of the crucible of Ga and In is opened, and the operation is performed, and the thickness is 1.2 Å / sec.
Undoped n-type Ga with a film thickness of 0.3 μm
_{A 1-X} In _X N (X = 0.12) thin film is prepared. Further, the shutter of the Mg crucible is simultaneously opened simultaneously with the shutter of the Ga and In crucibles to form an i-type Ga _1-X In _X N (X = 0.12) doped layer having a thickness of 0.05 μm. As a result, a gallium nitride based semiconductor multilayer structure was manufactured. The RHEED diffraction pattern after film formation shows a streak shape, indicating that the laminated thin film is flat and has good crystallinity.

Next, an electrode for injecting current is provided by performing a lithography process on the laminated thin film. The lithography process can be performed by a process using a normal photoresist material. As an etching method, a window for forming an electrode into which current is injected is formed by performing ion milling. Then, Al
The electrodes were formed by a vacuum deposition method.

The device obtained by this method was cut with a dicing saw, and wiring was performed using a gold wire with a wire bonder. FIG. 8 shows an element structure of the present invention. When a voltage of 15 V was applied to the electrodes of the device and a current of 40 mA was injected, blue-green light emission of 60 mcd was observed.

[0033]

Embodiment 3 n was obtained by MBE using ammonia.
An example in which a gallium nitride-based light emitting device is manufactured by sequentially stacking ⁺ -type, n-type, and i-type Al _1-x Ga _x N will be described.
An evaporation crucible 2 is placed in a vacuum vessel 21 as shown in FIG.
A gas source MBE equipped with 2, 23, 24 and 25, a gas cell 26 and a substrate heating holder 27 was used.

The evaporating crucible 21 is filled with Ga metal.
The mixture was heated to 020 ° C, the Al crucible 23 was charged with Al metal and heated to 800 ° C, and the crucibles 24 and 25 were charged with Mg and Si and heated to 280 ° C and 1200 ° C, respectively. Ammonia is used as a gas, and a gas cell 26 filled with alumina fibers is used to introduce the gas. The gas is heated at 370 ° C. and supplied at a rate of 5 cc / min by directly blowing the gas onto the substrate 26. did.

As the substrate 28, from the sapphire R surface,
A sapphire substrate having a substrate surface rotated 9.2 degrees using the R-plane projection of the sapphire c-axis as a rotation axis was used. The pressure in the vacuum vessel was 2 × 10 ⁻⁶ Torr during film formation. First, the substrate 28 is heated at 900 ° C. for 30 minutes, and then the film is formed while maintaining the temperature at 750 ° C. The film is formed by supplying Ga, Al and Si while supplying ammonia from the gas cell 26.
Simultaneously open the crucible shutters, set the Ga beam intensity to 5.51 × 10 ¹⁴ / cm ² · sec, and deposit 0.2 μm-thick Si at a deposition rate of 1.2 Å / sec. Doped n ⁺ -type Al _1-x Ga _x N
(X = 0.90) A thin film is prepared. Further, Ga and Al
Open only the shutter, to form an undoped n-type Al _{1 over} X Ga _x N layer of 0.1μm in thickness of the (X = 0.90). Thereafter, the shutters of the crucibles of Ga, Al and Mg were simultaneously opened, and an i-type Al1 _{-X having} a thickness of 0.05 μm was opened.
A gallium nitride-based semiconductor laminated structure was manufactured by forming a doping layer having a Ga _X N (X = 0.90) composition. The RHEED diffraction pattern after film formation shows a streak shape, indicating that the laminated thin film is flat and has good crystallinity.

Next, an electrode for injecting a current is provided by performing a lithography process on the laminated thin film. The lithography process can be performed by a process using a normal photoresist material. As an etching method, a window for forming an electrode into which current is injected is formed by performing ion milling. Then, Al
The electrodes were formed by a vacuum deposition method.

The device obtained by this method was cut with a dicing saw, and wiring was performed using a gold wire with a wire bonder. FIG. 9 shows an element structure of the present invention. When a voltage of 15 V was applied to the electrodes of the device and a current of 30 mA was injected, ultraviolet light emission of 1.2 mW was observed.

[0038]

The gallium nitride based semiconductor light emitting device according to the present invention has good crystallinity due to small lattice mismatch between the gallium nitride thin film and the substrate, and has an n ⁺ -type gallium nitride based semiconductor layer. Since a uniform electric field can be applied to the light-emitting layer, it is possible to obtain a high-performance light-emitting element having a uniform light-emission intensity distribution at a low voltage.

[Brief description of the drawings]

FIG. 1. Corundum hexagonal crystal of sapphire and R of the crystal
It is sectional drawing which shows a surface and a c-axis.

FIG. 2 is a cross-sectional view showing a plane obtained by rotating the sapphire R plane by 9.2 degrees using the R plane projection of the sapphire c-axis as a rotation axis.

FIG. 3 is a schematic view of an MBE apparatus used for producing a thin film.

FIG. 4 is an observation result of a RHEED diffraction pattern after film formation.

FIG. 5 is a schematic view of an MBE apparatus used for producing a thin film having a GaN-MIS type element structure produced in Example 1.

FIG. 6 shows a current-voltage measurement result of the GaN-MIS type structure element manufactured in Example 1.

FIG. 7 is a graph showing light emission characteristics of the GaN-MIS structure element manufactured in Example 1.

FIG. 8 shows a GaInN-MIS type device structure manufactured in Example 2.

FIG. 9 shows an element structure of an AlGaN-MIS type structure manufactured in Example 3.

FIG. 10 is a diagram showing a cross-sectional structure of a gallium nitride semiconductor light emitting device.

FIG. 11 is a diagram showing a cross-sectional structure of a GaInN-based light emitting device.

FIG. 12 is a diagram showing a cross-sectional structure of a GaN / GaInN-based multilayer light emitting device.

FIG. 13 is a diagram showing a cross-sectional structure of a GaN / Ga _1-x In _x N-based light emitting device.

[Explanation of symbols]

Reference Signs List 1 sapphire R surface 2 sapphire c-axis 3 sapphire c-axis R-plane projection 4 surface 9.2 degrees rotated from sapphire R-plane with sapphire c-axis R-plane projection as rotation axis 5 sapphire substrate 6 n-GaN layer 7 i-GaN layer 8 Al electrode 9 n-Ga _1-x In _x N layer 10 n ⁺ -Ga _1-x In _x N layer 11 i-Ga _1-x In _x N layer 12 p-Ga _1-x In _x n layer 13 p-GaN layer _{14 n-Ga 1-y In} y n layer _{15 p-Ga 1-y In} y n layer 16 Mg doped · i-GaN layer 17 n ⁺ -GaN layer 18 n ⁺ -Al _{1- x} Ga _x N layer 19 n-Al _1-x Ga _x N layer 20 i-Al _1-x Ga _x N layer 21 vacuum vessel 22 evaporating crucible 23 evaporating crucible 24 evaporating crucible 25 evaporating crucible 26 gas cell 27 substrate Heating holder 28 Substrate 29 Quadrupole mass spectrometer 30 Iopaneru 31 valve 32 cold trap 33 an oil diffusion pump 34 oil rotary pump 35 substrate heater 36 shutter 37 shutter 38 shutters

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-323880 (JP, A) JP-A-5-315647 (JP, A) JP-A-4-299876 (JP, A) JP-A-5-299876 190903 (JP, A) JP-A-59-228766 (JP, A) JP-A-51-126040 (JP, A) JP-A-56-59699 (JP, A) JP-A-4-321280 (JP, A) JP-A-2-229475 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 33/00 H01L 21/203 H01L 21/86 JICST file (JOIS)

Claims (2)

(57) [Claims] 1. A sapphire c-axis R
An n ⁺ -type gallium nitride-based semiconductor layer directly formed on a surface rotated by 9.2 degrees about the plane projection as a rotation axis is used as a substrate surface. Characterized in that it has at least one light-emitting layer made of a single-crystal or i-type single-crystal gallium nitride-based semiconductor layer, and has an electrode at a desired site for applying a voltage to the light-emitting layer. Gallium based semiconductor light emitting device. 2. In the MBE method, a crystal growth apparatus having a gas source for supplying a gaseous compound containing nitrogen and a solid source for supplying a Group III element is used to project a sapphire R plane to a sapphire c-axis R plane. As a rotation axis;
Forming a n ⁺ -type gallium nitride-based semiconductor layer on a substrate by supplying a gaseous compound containing nitrogen, a group III element, and an n-type dopant with the surface rotated twice as a substrate surface; Forming an n-type single-crystal gallium nitride-based semiconductor layer by supplying a gaseous compound and a group III element, and supplying a gaseous compound containing nitrogen, a group III element and a p-type dopant to form a p-type or i-type A method for manufacturing a semiconductor light emitting device, comprising at least a step of forming a single crystal gallium nitride-based semiconductor layer made of: