Method for preparing gallium nitride single crystal film

Abstract

The present invention is epitaxial growth method of monocrystal GaN film on heterogenous substrate. Monocrystal GaN film is grown on heterogenous substrate or sapphire substrate inside chemical vapor deposition apparatus. The growth process includes introducing hydrogen into reactor, heating the substrate to 1200; lowering the temperature after 10 min, leading in ammonia in the flow rate of 3000-8000 ml / min and hydrogen carried trimethyl gallium in the flow rate of 1-10 ml / min to grow GaN or AlN nucleating layer; in-situ annealing; maintaining substrate temperature at 700-1300 deg.c, leading trimethyl gallium into reactor to grow 1-500 nm GaN layer; lowering the molar V / III ratio to 0.5-2 and further growing GaN to 1-10000 nm thickness. The said process suppresses default generation, provides optimal monocrystal GaN film growing condition and thus has greatly raised crystal quality and photoelectronic characteristic.

Description

Technical field [0001] The invention relates to a method for growing a III-N compound film on a heterogeneous substrate with a large mismatch, in particular to a method for growing a GaN film on a heterogeneous substrate with a three-step growth method with a large mismatch. Background technique [0002] Wide band gap materials represented by III-N compounds such as GaN are the third-generation semiconductor materials after Si and GaAs and have received extensive attention. However, due to the limitations of GaN single crystal drawing technology, GaN-based films that are currently used in large numbers are grown on non-GaN substrates by epitaxial methods, using a two-step growth method, that is, nucleation layer growth at low temperature and GaN at high temperature. The layer grows normally. The specific operation is as follows: first grow a layer of 10-50nm GaN or AlN at 400-650°C, and then grow GaN at 900-1200°C after annealing at high temperature (900-1200°C). See: J. Cryst. G...

AI Technical Summary

Problems solved by technology

The two-step growth method is to grow GaN under N-rich conditions. The problem is that the optimal conditions for GaN growth cannot be guaranteed, which limits the further improvement of the optoelectronic properties of GaN single crystal thin films.

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