Method and device for growing high-purity semi-insulating silicon carbide single crystal

Abstract

The invention relates to a method and device for growing a high-purity semi-insulating silicon carbide single crystal and belongs to the technical field of single crystal growth. A crucible and thermal insulation materials for growing a SiC single crystal are pre-processed by utilizing a specific device, specific gas is introduced in the single crystal growth process, the donor impurities N, acceptor impurities B and metal ions impurities in the SiC single crystal are effectively reduced, the specific resistance is enhanced, the power output of high-frequency and high-power devices is prevented from being affected by the deep capture center of vanadium-doped semi-insulating SiC, and the high-purity semi-insulating silicon carbide single crystal is obtained.

Description

technical field [0001] The invention relates to a method and device for growing a high-purity semi-insulating silicon carbide single crystal, belonging to the technical field of single crystal growth. Background technique [0002] The semi-insulating SiC single crystal polished wafer is the best substrate for the preparation of wide-bandgap solid-state microwave devices at this stage, and it also plays a very important role in power devices and deep submicron devices. More importantly, in terms of electrical properties and thermal conductivity, semi-insulating SiC is a new generation of wide-bandgap semiconductor materials that have great application prospects in optoelectronic and microwave power devices. [0003] Researchers usually introduce deep-level impurity vanadium into SiC crystals to form deep compensation levels, which are located near the center of the forbidden band and can well bind carriers. Currently only vanadium-doped SiC exhibits high-resistance propertie...

AI Technical Summary

Problems solved by technology

However, vanadium-doped SiC also has some problems: the solubility of vanadium in SiC is very low, and it is easy to form precipitates, which will lead to the formation of defects such as micropipes, which seriously affects the crystal quality. More importantly, the vanadium-doped SiC substrate Deep trapping centers affect the power output of high-frequency high-power devices, so the preparation of high-purity semi-insulating SiC single crystals has become a current research hotspot

[0004] The key to high-purity semi-insulating SiC single crystal growth technology is to remove the two impurities B and N in the crystal. B is an impurity that coexists with graphite, and graphite crucibles, insulation materials, and SiC source materials will all adsorb N. Therefore, removing these two impurities impurity has some difficulty

Literature data show that most of the unwanted N in the crystal growth process comes from the device and the raw material itself. Researchers have tried to minimize the release of N during high temperature growth by using high-purity source materials and extremely pure equipment components that do not have high nitrogen content. N 2 , but this method is extremely difficult

The researchers also attempted to feed H during crystal growth 2 , by adjusting the silicon-carbon ratio to prevent N elements from entering the crystal, but simply using H 2 The method can not reduce the N content in the crystal to the content required by high-purity semi-insulating SiC, and this method has basically no effect on the removal of B and other impurities.

Images