JPH05315210A - Gallium arsenide phosphide mixed-crystal epitaxial wafer - Google Patents

Abstract

PURPOSE:To obtain a wafer wherein one side of crosshatches is rectlinear and it is suitable for a substrate as a quaternary mixed-crystal epitaxial wafer by using a compound single-crystal substrate whose substrate surface is a specific plane orientation as the plane orientation of the surface of a single-crystal substrate and which is composed of a group IIIb element and a group Vb element of the periodic table. CONSTITUTION:HCl a group IIIb component gas for epitaxial-layer formation use is introduced into Ga in a quartz board at 8cc/min; it is reacted with the a; a-is produced. On the other hand, the flow rate of hydrogen arsenide (AsH3), at a concentration of 10% which has been diluted with H2, as a group Vb component gas for epitaxial-layer formation use, is reduced gradually down to 252cc/min from 336cc/min. At the same time, the flow rate of hydrogen phosphide (PH3), at a concentration of 10%, which has been diluted with H2, as a group V component gas for epitaxial-layer formation use, is increased gradually up to 80cc/min from 0cc/min. A GaAs1-XPX composition-graded layer is formed. After that, a GaAs1-XPX composition-definite layer is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gallium arsenide phosphide mixed crystal epitaxial wafer having a linear lattice stripe pattern, or so-called Cross hatch, formed on the surface of the epitaxial wafer. ..

[0002]

2. Description of the Related Art A gallium arsenide phosphide epitaxial wafer is a substrate for manufacturing quaternary mixed crystal epitaxial wafers such as gallium arsenide phosphide / aluminum and gallium arsenide phosphide / indium, and LED arrays. Used as. Such a quaternary mixed crystal epitaxial wafer is used to manufacture optoelectronic devices such as light emitting diodes and laser diodes. The yield (non-defective product rate) and performance of the obtained devices are gallium arsenide arsenide epitaxial substrates used as substrates. It depends on the nature of the wafer.

A gallium arsenide phosphide epitaxial wafer is manufactured by a vapor phase epitaxial growth method in which the mixed crystal ratio can be easily controlled. The surface of the wafer obtained by the vapor phase epitaxial growth method is called a cross hatch. A grid-like striped pattern appears. It has been known that, as a substrate of a quaternary mixed crystal epitaxial wafer, a substrate in which at least one of the cross hatches is linear is suitable.

[0004]

A recording light source of an LED (light emitting diode) printer, which is one type of electrophotographic printer, has a length of 7 to 8 mm and a width of 2 to 3 mm, and 64 chips or LE with 128 LEDs
A D array is used. In order to manufacture such an LED array with high yield, it is necessary to prevent chipping of the chips when separating the chips from the wafer by dicing. It has been found to be suitable for this to use a wafer in which at least one of the cross hatches is linear.

The present inventor has conducted earnest studies for the purpose of obtaining a gallium arsenide arsenide epitaxial wafer suitable for a substrate of a quaternary mixed crystal epitaxial wafer in which at least one of the cross hatches has a linear shape. As a substrate for a gallium arsenide phosphide mixed crystal epitaxial wafer, a compound consisting of a Group IIIb element and a Group Vb element of the periodic table having a specific plane orientation on the substrate surface (hereinafter referred to as "III-V compound"). The inventors have found that the object of the present invention can be achieved by using a single crystal substrate, and have reached the present invention.

[0006]

The above object of the present invention is to provide a single crystal substrate of a compound comprising a Group IIIb element and a Group Vb element of the periodic table having a zinc blende type crystal structure, and a single crystal substrate on the substrate. In the gallium arsenide phosphide mixed crystal epitaxial wafer containing the formed gallium arsenide phosphide mixed crystal epitaxial film, one of the plane orientations included in the group shown below is selected as the plane orientation of the surface of the single crystal substrate. An epitaxial wafer having a plane orientation and at least one of cross hatches on the surface of the epitaxial film being linear, a (110) plane to a [110] direction or a (-1-1)
0] direction, the plane deviated by a deviation angle of 0.5 to 10 °. [1-10] direction or [-11] from (00-1) plane
0] direction, the plane deviated by a deviation angle of 0.5 to 10 °. [011] direction from the (100) plane or [0-1-
1] The surface deviated by 0.5 to 10 degrees. [01-1] direction or [0-1] from the (-100) plane
1] The surface deviated by 0.5 to 10 degrees. From the (010) plane in the [101] direction or [-10-
1] The surface deviated by 0.5 to 10 degrees. From the (0-10) plane in the [10-1] direction or [-10
1] The surface deviated by 0.5 to 10 degrees. Reached by.

Group III-V compounds having a zinc blende type crystal structure used in the production of single crystal substrates are group IIIb.
The group element is any one of Al, Ga, and In, and the group Vb element is one of P, As, and Sb.
Compounds consisting of certain elements, preferably gallium arsenide (G
aAs) or gallium phosphide (GaP) are suitable.
The single crystal of the above compound can be produced by the Cz method, the boat growth method, or the like.

The gallium arsenide phosphide epitaxial film is
A single crystal substrate cut out from the above single crystal is grown by an epitaxial growth method, preferably a vapor phase epitaxial growth method. According to the vapor phase epitaxial growth method, a cross hatch is clearly observed on the surface, and the mixed crystal ratio of gallium arsenide phosphide, that is, the x value of the formula GaAs _1-x P _x (where 1>x> It is preferable because adjustment of 0) is easy. As the single crystal substrate, it is preferable to use GaP or GaAs because it is easy to match the lattice constant and is easy to obtain.

The following plane orientations are suitable for the surface of the single crystal substrate. The following six types of planes are crystallographically equivalent planes. [110] direction or [-1-1] from (001) plane
0] direction, the plane deviated by a deviation angle of 0.5 to 10 °. [1-10] direction or [-11] from (00-1) plane
0] direction, the plane deviated by a deviation angle of 0.5 to 10 °. [011] direction from the (100) plane or [0-1-
1] The surface deviated by 0.5 to 10 degrees. [01-1] direction or [0-1] from the (-100) plane
1] The surface deviated by 0.5 to 10 degrees. From the (010) plane in the [101] direction or [-10-
1] The surface deviated by 0.5 to 10 degrees. From the (0-10) plane in the [10-1] direction or [-10
1] The surface deviated by 0.5 to 10 degrees.

When a substrate cut from a GaAs single crystal is used as the single crystal substrate, a deviation angle of 1 to 3 ° is preferable, and when a substrate cut from a GaP single crystal is used, a deviation angle of 4 to 7 ° is preferable. The surface orientation is above
The use of a single crystal substrate having a plane orientation other than the plane orientations described above is not preferable because the surface cross hatch does not become linear and a good quaternary mixed crystal epitaxial film cannot be obtained. As the vapor phase or liquid phase epitaxial growth method for the gallium arsenide phosphide mixed crystal epitaxial film, any conventionally known method may be used.

[0011]

In the gallium arsenide phosphide mixed crystal epitaxial wafer according to the present invention, the crosshatch has a linear shape,
Further, it is suitable as a substrate for producing a quaternary mixed crystal epitaxial wafer, and contributes to an improvement in the yield of light emitting diodes, laser diodes and the like using the quaternary mixed crystal epitaxial wafer. Further, when an LED array is manufactured using the wafer of the present invention, unevenness in brightness due to chipping of chips does not occur, so the array yield is improved.

[0012]

EXAMPLES The present invention will be described more specifically based on Examples and Comparative Examples. Example (Production of GaAs _0.6 P _0.4 epitaxial wafer) n
Silicon (Si) was added as a type impurity at 1.0 × 10 ¹⁸ atoms / cm ³ , and the crystallographic plane orientation was deviated by 2 ° ± 0.5 ° from the (001) plane in the [1-10] direction. A single crystal substrate having a surface was prepared. The GaAs single crystal substrate was initially 41
Although the thickness was 0 μ, it was changed to a thickness of 360 μ by the mechanical-chemical polishing treatment subsequent to the degreasing step using the organic solvent.

Next, the polished GaAs single crystal substrate and a quartz boat containing high-purity Ga were set in predetermined places in a horizontal quartz epitaxial reactor having an inner diameter of 70 mm and a length of 1000 mm. Argon (Ar) was introduced into the epitaxial reactor to sufficiently replace and remove air, and then high-purity hydrogen gas (H
₂ ) was introduced at 2500 cc / min, the flow of Ar was stopped, and the temperature rising step was started. Quartz boat set area containing Ga and G
The temperature of the aAs single crystal substrate set area is 830 ° C.
And after confirming that the temperature is maintained at 750 ℃, GaAs
Vapor phase growth of _0.6 P _0.4 epitaxial film was started.

First, prior to the formation of the GaAs _0.6 P _0.4 epitaxial layer, a high-purity hydrogen chloride gas (HCl), which is an erosive gas, is introduced at 90 cc / min for a large amount of 5 minutes, and the above G
The surface of the aAs single crystal substrate was eroded. Then, the supply of HCl for substrate erosion was stopped, and a GaAs _0.6 P _0.4 epitaxial layer was formed.

That is, diethyl tellurium ((C ₂ H ₅ ) ₂ Te) gas diluted to a concentration of 10 ppm with H ₂ gas is supplied at a rate of 15 minutes per minute.
cc was introduced, and HCl was introduced into Ga in an 18 cc quartz boat per minute as a group IIIb component gas for forming an epitaxial layer in the same direction as the substrate erosion gas flow (HCl).
GaCl is produced by reacting with Ga, while H _{2 is used} as a Vb group component gas for forming the epitaxial layer.
The flow rate of 10% hydrogen arsenide (AsH ₃ ) diluted with was gradually decreased from 336 cc / min to 252 cc for the first 80 minutes, and at the same time diluted with H ₂ which is a group V component gas for forming the epitaxial layer. 10% concentration of hydrogen phosphide (P
H ₃ ) flow rate is gradually increased from 0 cc to 80 cc per minute G
aAs _1-X P _X composition gradient layer (epitaxial layer in which x gradually increases from 0 to 0.4) is formed, and then GaAs is formed.
_1-X P _X (x = 0.4) The process proceeded to form a constant composition layer.

That is, for the next 60 minutes, the above (C ₂ H ₅ ) ₂ T
The formation of the epitaxial wafer was completed by growing a GaAs _0.6 P _0.4 constant composition layer while introducing HCl, AsH ₃ and PH ₃ in contact with e and Ga in a constant amount of 15 cc, 18 cc, 252 cc and 80 cc, respectively. When observing the surface of the taken out epitaxial wafer with a microscope,
As shown in the figure, it was found that the horizontal direction of the cross hatch was straight.

Comparative Example 1 As a GaAs substrate used in the same manner as in Example, n
A single crystal substrate having silicon (Si) added as a type impurity of 1.0 × 10 ¹⁸ atoms / cm ³ and having a crystallographic plane orientation deviated by 2 ° in the [110] direction from the (001) plane is used. I was there. As a result of observing the surface of the epitaxial wafer obtained as a result, it was found that the cross hatch was wavy as shown in FIG.

Comparative Example 2 As a GaAs substrate used in the same manner as in Example, n
Silicon (Si) was added as a type impurity at 1.0 × 10 ¹⁸ atoms / cm ³ and the crystallographic plane orientation was deviated from the (001) plane by 1 ° in the [110] direction by 1 ° in the [-110] direction. A single crystal substrate having a surface was used. As a result of observing the surface of the epitaxial wafer obtained as a result, it was found that the cross hatch was wavy as shown in FIG.

[Brief description of drawings]

FIG. 1 is a photomicrograph (magnification: 50 times) showing the crystal structure of the surface of a gallium arsenide phosphide mixed crystal epitaxial wafer according to the present invention.

FIG. 2 is an example of a micrograph (magnification: 50 times) showing a crystal structure of a surface of a gallium arsenide phosphide mixed crystal epitaxial wafer according to a conventional technique.

FIG. 3 is another example of a micrograph (magnification: 50 times) showing the crystal structure of the surface of a gallium arsenide phosphide mixed crystal epitaxial wafer according to the prior art.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H01S 3/18

Claims (3)

[Claims] 1. A single crystal substrate of a compound comprising a Group IIIb element and a Group Vb element of the periodic table having a zinc blende type crystal structure, and a gallium arsenide phosphide mixed crystal epitaxy formed on the substrate. In a gallium arsenide phosphide mixed crystal epitaxial wafer containing a yar film, the surface orientation of the single crystal substrate has one of the plane orientations included in the group shown below. An epitaxial wafer, wherein at least one of the surface cross hatches is linear. [110] direction or [-1-1] from (001) plane
0] direction, the plane deviated by a deviation angle of 0.5 to 10 °. [1-10] direction or [-11] from (00-1) plane
0] direction, the plane deviated by a deviation angle of 0.5 to 10 °. [011] direction from the (100) plane or [0-1-
1] The surface deviated by 0.5 to 10 degrees. [01-1] direction or [0-1] from the (-100) plane
1] The surface deviated by 0.5 to 10 degrees. From the (010) plane in the [101] direction or [-10-
1] The surface deviated by 0.5 to 10 degrees. From the (0-10) plane in the [10-1] direction or [-10
1] The surface deviated by 0.5 to 10 degrees. 2. A patent in which the compound consisting of a Group IIIb element and a Group Vb element of the periodic table having a zinc blende type crystal structure is gallium arsenide, and the deflection angle is 1 to 3 °. The epitaxial wafer according to claim 1. 3. A patent in which the compound consisting of a Group IIIb element and a Group Vb element of the periodic table having a zinc blende type crystal structure is gallium phosphide and the deflection angle is 4 to 7 °. The epitaxial wafer according to claim 1.