JPS62171999A - Epitaxy of iii-v compound semiconductor - Google Patents

Abstract

PURPOSE:A group-IV elementary semiconductor layer of the same as or different from the base semiconductor is allowed to grow epitaxially on the base surface, then a single atomic layer of a group V element is formed thereon, and a III-V compound semiconductor from the group V element used is allowed to grow thereon epitaxially whereby a high-purity semiconductor layer of III-V compound is formed. CONSTITUTION:A Si crystal of <100> or <111> face orientation is used as a IV-group semiconductor base, and a group-IV semiconductor layer 2 the same as or different from the base such as Si or Ge is allowed to grow epitaxially so that the thickness of the layer becomes integral times that corre sponding to double atom layer of the semiconductor. Then, a single atom layer 3 of group-V element such as P is formed by adsorption on its surface, further, a semiconductor layer 4 of III-V compound from the group V element used such as GaP is formed epitaxially thereon. The process enables the economical mass-production of high-quality III-V compound semiconductor layers free from antiphase boundary.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for epitaxial crystal growth of M-V group compound semiconductors.

(Prior art and problems to be solved by the invention) GaA
Although IV group compound semiconductors represented by s+GaP have excellent electrical and optical properties, they are not only expensive, but also have drawbacks such as being mechanically brittle and having poor thermal conductivity. Therefore, it is inexpensive and has excellent mechanical and thermal properties.
A group III semiconductor of t st +Go is used as a substrate, and J
Attempts have been made to realize a -V group compound semiconductor that is inexpensive and has excellent mechanical and thermal properties by epitaxially growing a -V compound semiconductor.

However, conventionally, a X-V group compound semiconductor layer formed on a group I semiconductor substrate has an electrical property.

It contains a large number of planar defects called anti-phase (e/4) defects that are extremely optically active, and it has not yet been possible to obtain a high-quality crystal that can be applied to device formation.

Hereinafter, the above-mentioned anti-7AIDS pandry will be explained using as an example a case where KGaP is epitaxially grown on a st substrate with a surface orientation <Zoo>.

Generally, the surface of an 81 substrate obtained by chemical surface treatment has irregular irregularities on an atomic scale. If GaP is epitaxially grown on a Si substrate with such a surface condition, since GaP has a crystal structure in which Ga atomic layers and P atomic layers are sequentially and alternately stacked, the resulting 90aP crystal will contain Crystal planes are formed in which Ga and Ga or P and P are adjacent to each other, which should not exist. This crystal plane is the above-mentioned plane defect called the anti-7AIDS pandary. As described above, antiphase pandas are planar defects that are extremely active electrically and optically, and therefore devices fabricated using GaP crystals containing many such defects are extremely difficult to put into practical use.

(Means for Solving the Problems) The present invention has been proposed in order to solve the above-mentioned problems, and its purpose is to provide an anti-7
An object of the present invention is to provide a method for epitaxial crystal growth of an IV group compound semiconductor, which allows the growth and formation of a high-quality L-V group compound semiconductor layer without AIDS pandas.

In order to achieve the above object, the present inventors conducted various experiments and found that a group IV semiconductor layer of the same type or a different type was formed on the surface of a group IV semiconductor substrate with a plane orientation of 400> or 411>. Epitaxial growth is performed so that the step generated on the growth surface is an integer multiple of the thickness equivalent to a diatomic layer of the group (1) semiconductor layer, and a single atom of a group V element is further grown on the surface of the group (1) semiconductor layer. If a group IV compound semiconductor layer having the group V element as a constituent element is epitaxially grown after forming the layer by adsorption, an anti-7
It has been discovered that a high-quality Group II' compound semiconductor layer without AIDS pandas can be obtained. In order to make this discovery, at least a 1V group semiconductor layer of the same type or a different type is grown on the surface of a 1V group semiconductor substrate with a plane orientation of 400> or 411>, and the step difference that occurs on the growth surface is monitored. However, a first step of epitaxially growing the step so that the step is an integral multiple of the thickness equivalent to a diatomic layer of the group (I) semiconductor layer, and a step of growing the group (I) semiconductor layer formed by the first step. a second step of adsorbing and forming a monoatomic layer of a group V element on the surface; and a second step of forming a l-V group compound semiconductor layer containing the group V element as a constituent element. The present invention proposes a method for epitaxial crystal growth of a group I-v compound semiconductor, which is characterized by comprising a third step of epitaxial growth on the surface of a monoatomic layer of a group element.

FIG. 2 shows an example in which the step on the Si substrate has a thickness equivalent to one atomic layer. In this case, even if P atomic layers and Ga atomic layers are alternately and correctly stacked, crystal planes in which P atoms are adjacent to each other, that is, antiphase pandries are formed.

In contrast, FIG. 3 shows an example in which the step on the St substrate has a thickness equivalent to a diatomic layer, and in this case, the P atomic layer and the G
If the a-atomic layers are stacked alternately and correctly, anti-7AIDS pandaries will not be formed.

Embodiments of the present invention will be described below, taking as an example a case where GaP is epitaxially grown on an 81 substrate using a molecular beam ♂taxial apparatus as an epitaxial growth apparatus. Note that this example is just an illustration, and other crystal growth apparatuses and other methods may be used without departing from the spirit of the present invention.
Needless to say, the present invention can also be applied to the taxial growth of group V compound semiconductor materials.

Figure 1 shows Ga formed on a Si substrate with a plane orientation of 400>.
A cross section of a P semiconductor layer is shown. In the figure, 1 is an Si substrate as an example of a group III semiconductor substrate, 2 is a group III semiconductor layer of the same type or different type, and the level difference generated on the growth surface is
As an example of the first step of epitaxially growing a Si epitaxial layer to have a thickness equivalent to a diatomic layer of the group semiconductor layer, 3 is a group semiconductor layer formed in the first step. As an example of the second step of adsorbing and forming a monoatomic layer of a group V element on the surface of the P monoatomic layer, 4 is a 1-V group compound semiconductor layer having the group V element as a constituent element. As an example of the third step of epitaxially growing the monoatomic layer of the group V element formed in the step, an epitaxial layer of GaP was formed as follows. First, after degreasing and cleaning the AT substrate (using an organic solvent), the steps of oxide film formation and etching are repeated several times to form a clean oxide film on the surface of the Sl substrate, and then it is inserted into the molecular beam Evita kinial apparatus. did. Next, the above S
One substrate is heat-treated in a temperature range of 700°C to 900°C,
The oxide film formed on the surface of the St substrate was removed. next,
Sl is evaporated using an electron beam evaporation source, and an 81-layer pitaxial layer is grown at a growth rate of 0.5X/S~IO! /8.
While observing the vibration intensity of the specular reflection point of the diffraction image due to the incidence of the reflected high-speed electron beam in the <100> direction while keeping the St substrate temperature in the range of 300° to 700°C, we observed that the steps generated on the growth surface of the Si epitaxial St was epitaxially grown on the above-mentioned Sl substrate so that the thickness was an integral multiple of the thickness corresponding to the outside of the diatomic layer. As a result, the growth rate was 3.0
/S Below, stable oscillations of the reflection high-speed electron diffraction image were obtained under the condition of the substrate temperature of 400°C to 500°C, and the step generated on the growth surface of the S1 pitaxial layer was a diatomic layer of the 81st pitaxial layer. It became clear that the epitaxial growth was made to be an integral multiple of the thickness corresponding to the outside. Next, P is evaporated using a Knudsen cell, and s
At a substrate temperature of 500° C., a monoatomic layer of P was adsorbed and formed on the surface of the Si epitaxial layer formed in the first step. Next, Ga and P were evaporated using a Knudsen cell, and the growth rate was 0.5X/S to IOX/8.
．． A GaP epitaxial layer was grown epitaxially with the SL substrate temperature in the range of 0° C. to 700° C. and the partial pressure ratio of the A-group element to the V-group element set to 10. As a result, a GaP epitaxial layer with an extremely smooth growth surface was obtained when the Si substrate temperature was 550° or less and the growth rate was 5.0X/S or less in the third step. Furthermore, the obtained GaP epitaxial layer was melted by KOHK.
As a result of etching, it was revealed that anti-7AIDS pandas do not exist in the GaP-engineered taxial layer. In addition, in order to evaluate the crystallinity of the obtained GaP epitaxial layer, we performed double-crystal X-ray diffraction and HatA measurements, and as a result, we obtained a half-value width of the (400) diffraction line and a carrier concentration comparable to that of a single crystal. It became clear that high-quality crystallinity was obtained.

In the above embodiments, epitaxial growth is performed using a molecular beam epitaxy apparatus, but for example, in the third step, a metal-organic chemical vapor deposition apparatus or a liquid phase epitaxy apparatus, which can be expected to have a higher growth rate and mass productivity, is used. It is also possible to use

Furthermore, in the above embodiments, an Sl substrate is used as the group ■ semiconductor substrate, a St epitaxial layer is used as the group ■ semiconductor layer, a P monoatomic layer is used as the monoatomic layer of the group V element, and a GaP epitaxial layer is used as the group ■-■ compound semiconductor layer. Regarding the example of the layer, 9 describes a G@substrate as a group III semiconductor substrate and 81 as a group III semiconductor layer epitaxially grown in the first step.
゜Ge*S i ,□Gex is epitaxially grown in the third step ■GaAs, 1nP was selected as the -V group compound semiconductor layer and crystal growth was attempted, and the same effect as in the previous example was obtained.

(Effects of the Invention) As explained above, according to the method for epitaxial crystal growth of layer-V group compound semiconductors according to the present invention, it is possible to grow high-quality epitaxial crystals of ■-V group compound semiconductors on group ■ semiconductor substrates. Therefore, it has the effect of bringing about great mass productivity and economic efficiency.

[Brief explanation of drawings]

Figure 1 shows Ga formed on an 81 substrate with a plane orientation of 400>.
FIG. 2 shows the atomic arrangement when the step on the Sl substrate corresponds to a monoatomic layer, and FIG. 3 shows the atomic arrangement when the step corresponds to a diatomic layer. DESCRIPTION OF SYMBOLS 1...St substrate, 2...Sl processed taxial layer formed on the St substrate in the first step, 3...St formed on the 81st layer pitaxial layer in the second step.
An epitaxial layer, 3...8i, is formed in a second step on the epitaxial layer, and a P monoatomic layer, 4...P
A GaP epitaxial layer formed in the third step on a monoatomic layer. Figure 1, -5i l pull E i deficiency. 2.--Si epitaxial layer 9 4I layer 3.Pwi layer 4.-GOP epitaxy layer

Claims (1)

[Claims] At least, a group IV semiconductor layer of the same type or a different type is grown on the surface of a group IV semiconductor substrate having a plane orientation of <100> or <111>, while monitoring the level difference occurring on the growth surface. a first step of growing epitaxially so that the thickness of the group IV semiconductor layer is an integral multiple of the diatomic layer thickness; and
a second step of adsorbing and forming a monoatomic layer of a group V element on the surface of a group V semiconductor layer; and a step of forming an atomic layer of a group V element by adsorption;
and a third step of epitaxially growing a group II-V compound semiconductor layer on the surface of the monoatomic layer of the group V element formed in the second step.
A method for epitaxial crystal growth of III-V compound semiconductors.