JPH0684796A - Method for growing semiconductor crystal - Google Patents

Abstract

PURPOSE:To grow a high-quality crystal by suppressing the elimination of group V molecules during the course of molecular beam epitaxy of a III-V compound semiconductor. CONSTITUTION:In the title method by which a III-V compound crystal containing arsenic or phosphorus is grown on a compound semiconductor substrate having its plane orientation in (100) plane by molecular beam epitaxy the crystal is grown by using such a substrate that its plane orientation is inclined by 0.5 deg.-6 deg. in an arbitrary direction under a growing condition where the elimination of group V molecules occurs on the surface of a substrate having accurate plane orientation in (100) plane. On the surface having accurate plane orientation in (100) plane, a high-quality crystal in which the elimination of group V molecules hardly occurs can be obtained even under a growing condition where the surface morphology of the substrate becomes rough.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crystal growth method for a compound semiconductor, and more particularly to a crystal growth method by a molecular beam epitaxy method.

[0002]

2. Description of the Related Art In crystal growth using a molecular beam epitaxy method, group V molecules and group III atoms are supplied from separate leasing sources and irradiated onto a substrate. At this time, the crystal quality is V / III, which is the ratio of the number of irradiated group V molecules and group III atoms.
It depends largely on the ratio and the substrate temperature. When the number of group V molecules is small, the stoichiometry of the crystal is not maintained and the surface becomes rough. In this case, increasing the V / III ratio results in V
It is well known that the detachment of the tribe is suppressed (for example, Journal, Of, Applied Physics, Asahi K, et al., 1981, 52, 2852).

[0003]

In this conventional growth method, the required V / III ratio must be made very large when the substrate temperature is high. For example, in the selective growth using the molecular beam epitaxy method, a large crystal growth selectivity between SiO ₂ and a semiconductor is indispensable, but high temperature growth is indispensable for this, and a high V / III ratio is required. Is required (Aptide Physics Letter, 1987, Volume 51, 1
512 pages, Akira Okamoto, et al.). However, there is an upper limit on the number of group V molecules that can be irradiated due to the device configuration, so the upper limit of high temperature growth is limited by the desorption temperature of this group V molecule. Thus, there is a problem in obtaining high quality crystals at high temperature.

An object of the present invention is to provide a growth method capable of growing a high-quality compound semiconductor crystal with little group V elimination even at high temperatures in the molecular beam epitaxy method.

[0005]

A method for growing a semiconductor crystal according to the present invention is a method for growing a group III-V compound crystal on a compound semiconductor substrate by a molecular beam epitaxy method. It is characterized in that the growth is performed using a substrate whose substrate plane orientation is tilted in an arbitrary direction from the (100) plane within a range of 0.5 to 6 degrees under a growth condition that causes group V desorption.

[0006]

Embodiments of the present invention will now be described with reference to the drawings. 1 and 2 are a micrograph showing a surface morphology of a semiconductor crystal film grown using the present invention name and a micrograph showing a surface morphology of a semiconductor crystal film grown using a conventional technique, respectively. The sample of FIG.
As the nP substrate, a substrate tilted by 2 ° in the (111) A direction in the (100) plane direction was used, and the sample of the conventional example in FIG. 2 was a substrate having an accurate (100) plane direction. Each substrate was fixed on the same substrate holder with In after ordinary surface chemical etching and introduced into a molecular beam epitaxial growth apparatus, and then an InP crystal was grown to 1 μm. The growth of the InP crystal is performed by using a gas source molecular beam epitaxy method to grow fixed In
Sauce and phosphine in cracking cell at 950 ℃
Was carried out using the P ₂ molecule decomposed in step 1. The phosphine flow rate is 13 sccm, the substrate temperature is 545 ° C., and the growth rate is
It was 0.4 μm / hour.

In the semiconductor crystal film of FIG. 2, surface roughness which is considered to be due to desorption of phosphorus molecules was observed, but in the semiconductor crystal film of FIG. 1, such surface roughness was not observed and mirror surface growth was observed. . As described above, according to the present invention, even under the growth condition in which the surface morphology is deteriorated due to the elimination of the group V atom in the crystal growth on the substrate having the accurate (100) plane orientation,
It is clear that high quality epitaxial films with a mirror surface morphology can be grown.

In this embodiment, InP on the InP substrate has been described as an example, but the substrate is a GaAs substrate or InA.
The epitaxial growth film is not limited to InP, but may be GaAs, InAs, InG.
Any III-V group compound semiconductor containing arsenic or phosphorus such as aAs or InAlAs may be used. The growth method is not limited to the gas source molecular beam epitaxy method, and may be a molecular beam epitaxy method such as a solid source molecular beam epitaxy method or a chemical beam epitaxy method. In addition, the fine tilt angle is 0.5
The above high-quality Tr film can be grown in the range of 6 to 6 degrees.

[0009]

As described above, according to the present invention, by using a substrate having a plane orientation inclined in the range of 0.5 to 6 degrees from the accurate (100) plane orientation, III-V compound semiconductor growth is achieved. High quality crystals can be grown up to high temperature.

[Brief description of drawings]

FIG. 1 is a view showing a microscope photograph of surface morphology of a semiconductor crystal film according to the present invention.

FIG. 2 is a view showing a micrograph of a surface morphology of a semiconductor crystal film according to a conventional technique.

Claims (1)

[Claims] 1. An element constituting a III-V group compound semiconductor crystal is supplied to the surface of the compound semiconductor substrate in the form of an atom or a molecule, and the III-V group compound semiconductor crystal is placed on the compound semiconductor substrate by a molecular beam epitaxy method. In the method of growing by (10), the substrate plane orientation is (10)
(0) A method for growing a semiconductor crystal, which comprises supplying a group III or V group atom or molecule to a compound semiconductor substrate tilted in an arbitrary direction with respect to the (0) plane within a range of 0.5 to 6 degrees.