AlN single crystal substrate production apparatus and application method thereof

Abstract

The invention provides an AlN single crystal substrate production apparatus and an application method thereof. The main body of the AlN single crystal substrate production apparatus is a high temperature resistant crucible and the crucible is divided into two parts, namely a crystal growth chamber and a raw material chamber. A gas pipe of ammonia gas or nitrogen gas or mixed ammonia gas and nitrogen gas is arranged on the sidewall of the crystal growth chamber, and a gas outlet is formed in a position opposite to the gas pipe; a substrate is fixed on the top of the reaction chamber; a carrier gas pipe is arranged at the bottom of the raw material chamber; raw materials are placed at the bottom of the raw material chamber; and the growth chamber is separated from the raw material chamber by a perforated separator. The crucible can be heated by heaters around the crucible, or directly heated by use of the crucible. According to the AlN single crystal substrate production apparatus, a large-size cheap sapphire substrate is taken as seed crystal for AlN crystal growth and the problem of expensive seed crystal of the PVT apparatus is solved; and besides, compared with halide vapor phase epitaxy (HVPE) equipment, the growth temperature of the AlN single crystal substrate production apparatus is higher and closer to the balance growth temperature of the AlN crystal, and therefore, the grown crystal is higher in quality.

Description

technical field [0001] The invention relates to the technical field of semiconductor equipment manufacturing and semiconductor materials, in particular to the production equipment and usage method of AlN single crystal substrate. Background technique [0002] GaN, AlN and their alloy AlGaN are excellent materials for making light-emitting diodes (LEDs), laser diodes (LDs), detectors, and high-frequency, high-temperature, and high-power electronic devices in the ultraviolet to deep ultraviolet band. Due to the lack of homogeneous substrates, these devices are usually fabricated on heterogeneous substrates such as silicon (Si), silicon carbide (SiC), or sapphire. However, there is a large lattice mismatch and thermal mismatch between the heterogeneous substrate and the epitaxial layer, resulting in more defects such as dislocations in the epitaxial film, which in turn limits the performance and service life of the fabricated device. A better solution is to use AlN single crys...

AI Technical Summary

Problems solved by technology

However, the AlN single crystal substrate prepared by the PVT method usually uses AlN powder as a raw material, and the AlN powder currently on the market has low purity and contains a large amount of impurities, so it cannot be directly used for growth.

AlN powder is usually sintered to remove impurities before growth, which increases the complexity of the process and production costs, and is not conducive to the commercialization of AlN single crystal substrates.

One solution is to use high-purity metal Al as the source material. However, since metal Al and nitrogen will react on the surface of the raw material, the AlN generated on the surface will hinder the evaporation of metal Al, thereby limiting the growth of AlN crystals.

In addition, the working temperature of the PVT method is very high, usually above 2200 ° C, and its equipment manufacturing is very difficult. Commonly used cheap substrate materials such as sapphire are unstable at this temperature, so SiC can only be used as the substrate or self-nucleation to grow

AlN grown by self-nucleation is usually polycrystalline, and it is difficult to prepare large-sized AlN single crystal substrates; while SiC substrates are expensive, the cost of growing AlN single crystal substrates on SiC substrates is very high, and it is difficult to achieve commercial applications

[0005] Generally speaking, in the existing methods for preparing AlN single crystal substrates, the growth rate of HVPE equipment is slow, and it is easy to be corroded, and the stability of the equipment is poor; while PVT equipment is faced with problems such as low purity of raw materials and expensive substrates.

These problems restrict the commercial application of AlN single crystal substrates, and also restrict the development of AlGaN-based ultraviolet-deep ultraviolet devices

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