JPS62138399A - Production of single crystal film - Google Patents

Abstract

PURPOSE:To grow the titled single crystal film having excellent crystallinity by previously nitriding the surface of a GaAs crystal substrate when the single crystal film of GaN or AlN is grown on the GaAs crystal substrate. CONSTITUTION:The GaAs crystal substrate is arranged in a reaction tube, the inside of the reaction tube is evacuated, then the substrate is heated, and a gaseous hydrogen current contg. hydrazine is introduced to nitride the surface of the substrate. Then a gaseous hydrogen current contg. hydrazine and a gase ous hydrogen current contg. trimethylgallium a trimethylaluminum are intro duced to grow the single crystal of GaN or AlN on the nitrided substrate. Consequently, a single crystal film having excellent crystallinity can be grown at a comparatively low temp. with a simple device without necessitating the use of electron cyclotron resonance plasma, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention provides a method for depositing gallium nitride (CG&N) or aluminum nitride (Am) on a gallium arsenide (GaAs) crystal substrate.
The present invention relates to a method for forming a single crystal film.

[Conventional technology]

Conventionally, in the case of a cell in which a GaN or AIN single crystal film is grown on a GaAm substrate, a method using ECR (electron cyclotron resonance) plasma has been mainly adopted.

This is because GaNe AIN is grown at a low temperature that does not degrade the surface of the GaAs substrate. However, this method tends to introduce impurities and requires a microwave oscillator capability to generate ECR plasma in the manufacturing equipment. Therefore, G at a sufficiently low temperature without using plasma
As a method for growing aN and AJN, a growth method using hydrazine (N2H4) as the nitrogen raw material has been considered.

[Problem that the invention seeks to solve]

However, even if GaN or AJN is grown directly on a GaAm substrate, a film with good crystallinity cannot be obtained.
An object of the present invention is to provide a method for manufacturing a single crystal film of aNe AIN.

[Means for solving problems]

In the present invention, after nitriding the surface of the gallium arsenide crystal substrate,
This method of manufacturing a single crystal film is characterized by growing a single crystal film of gallium nitride or aluminum nitride thereon.

[Effect]

At present, no clear knowledge regarding the principle of operation of the present invention has been obtained. However, when the GaAs crystal surface is nitrided, Ga-N bonds are formed in the nitrided part.
Then, GaN is applied to the nitrided GaAs surface.

When AJN is grown, it is presumed that the growth is performed using nitrogen as a common element and also by relaxing the lattice mismatch between GaAs, GaN, and AJN.

〔Example〕

Examples of the present invention are shown below.

In this example, trimethylgallium (TMG) is used as a gallium raw material, trimethylaluminum (TMA) is used as an aluminum raw material, and hydrazine (N2H4) is used as a nitrogen raw material and G
It was used as a gas for nitriding aAs.

Etched GaAs (1
11) After introducing the substrate, the inside of the tube was evacuated to 1X10 Torr using an ion pump and a liquid pump. Thereafter, hydrazine was poured into the tube and heat treatment was performed at a substrate temperature of 500° C. for 4 hours at normal pressure. At this time, the temperature of hydrazine is 2
At 0℃, the flow rate of hydrogen to bubble hydrazine is 500 per minute.
cc, and in addition hydrogen was flowed through the reaction tube at 11 per minute.

This resulted in approximately 150X nitridation of the GaAs surface.

Following the nitriding treatment of the substrate, GaN or AIN was grown. The growth conditions were a substrate temperature of 500°C;
The flow rate of hydrogen to bubble hydrazine is 1000cc per minute.
The flow rate of hydrogen bubbled through TMG (-15°C) was set to 10 cc per minute, or the flow rate of hydrogen bubbled through TMA (20°C) was set to 2 Qcc per minute, and hydrogen was added to make the total flow rate 31 cc per minute. . Further, the pressure was maintained at 20 Torr.

Through this growth, approximately 1 μm of GaN or AJN is formed in 91 hours.
A single crystal film was obtained. Growth is C for both GaN and AJN
Proceeded along the axial direction.

The normalized yield determined from the backscattered ion intensity of 2RhV helium ions in the C-axis and the direction tilted from the C-axis is 5% for GaN and 7% for AIN when nitriding is performed.
It was confirmed that nitriding is effective in improving the crystallinity, with 18% for GaN and 22% for AJN when nitriding was not performed.

〔Effect of the invention〕

As described above, according to the method of the present invention, GaN with good crystallinity,
AA! This has the effect that N crystal can be manufactured on a GaAg substrate.

Claims (1)

[Claims] (1) A method for producing a single crystal film, which comprises nitriding the surface of a gallium arsenide crystal substrate and then growing a single crystal film of gallium nitride or aluminum nitride thereon.