Method for stably growing GaN crystal material at high rate in HVPE

Abstract

The invention discloses a method for stably growing a GaN crystal material at high rate in HVPE. The method comprises the following steps: when the HCl gas introduced into a Ga boat containing liquid Ga goes through an improved HCl gas circulation way, the HCl gas is sufficiently mixed with metal Ga for reacting to generate a GaCl gas; and after escaping from the top liquid level of the liquid Ga, the GaCl gas is guided into a growth zone and reacts with NH3 to generate GaN for growth. In the invention, since the HCl is prevented from directly entering the growth zone and approaching the seed crystal, the growth rate of the GaN crystal material is increased; and due to the increase of reaction time, the problems of GaCl concentration change in the growth zone and consequent decrease of the GaN growth rate caused by the Ga liquid level decrease can be improved so as to enhance the growth stability of GaN crystal.

Description

technical field [0001] The invention relates to the field of semiconductor materials, in particular to a method for stably growing GaN crystal materials at a high rate in HVPE. Background technique [0002] The hydride vapor phase epitaxy (HVPE) method has become one of the mainstream GaN material growth methods due to its relatively simple equipment and relatively fast growth rate. Japan's Sumitomo and Hitachi Cable, China's Dongguan Sino Nitride and Suzhou Nanowin have grown 2-inch GaN self-supporting substrate materials using HVPE. The method uses hydrogen chloride (HCl) by reacting with liquid metal gallium (Ga): [0003] Ga(l)+HCl(g)→GaCl(g)+H 2 (g) [0004] The generated gallium chloride (GaCl) is introduced into the growth area and ammonia (NH 3 )reaction: [0005] [0006] GaN material is thus generated. [0007] In HVPE, generally, HCl gas flows through the liquid metal Ga liquid surface in the Ga boat [Chinese Patent CN 204138762U], and reacts at the gas-l...

AI Technical Summary

Problems solved by technology

This kind of HCl gas circulation path, on the one hand, as the HCl gas continues to flow in, the liquid level of the liquid metal Ga in the Ga boat continues to drop, and the time for the HCl gas to reach the Ga liquid level is prolonged, resulting in a decrease in the generated GaCl, and the growth zone V The / Ⅲ ratio changes, which ultimately affects the stability of GaN crystal growth [K.Lekhal et al.Jpn.J.Appl.Phys.,55,05FF03,2016.]

On the other hand, due to the existence of part of the HCl gas that has not contacted the metal Ga liquid surface, it is transported to the growth region before it can react, and the appearance of HCl gas in the growth region will make GaCl and NH 3 The reaction is inhibited, hindering the generation of GaN material

Chinese patent CN 101225547A pointed out that in order to increase the growth rate in the current HVPE, the flow rate of HCl must be increased to generate more reactant GaCl, but at the same time more HCl will enter the growth region, which will inevitably affect the generated GaN produces a strong corrosion effect, thus hindering the further increase of the growth rate of GaN crystal by HVPE method

It proposes to use gallium vapor to directly react with ammonia gas to form GaN to increase the growth rate, but the evaporation of gallium vapor in this scheme is not easy to control and is not suitable for industrial production

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