Epitaxial preparation method of P type heavily-doped silicon carbide film by controlling flow rate of hydrogen gas

Abstract

The invention relates to an epitaxial preparation method of a P type heavily-doped silicon carbide film by controlling a flow rate of a hydrogen gas. The preparation method comprises the following steps: (1) placing a silicon carbide substrate into a reaction chamber of silicon carbide CVD (chemical vapor deposition) equipment, and vacuating the reaction chamber; (2) introducing H2 into the reaction chamber until the gas pressure of the reaction chamber reaches 100mbar, keeping the gas pressure of the reaction chamber constant, gradually increasing the flow rate of the H2 to 60 L / min, and continuously introducing H2 into the reaction chamber; (3) switching on a high-frequency coil induction heater RF, gradually increasing the power of the heater, and carrying out in-situ etching when the temperature of the reaction chamber is greatly increased to 1400 DEG C; and (4) keeping the temperature and the pressure intensity constant while the temperature of the reaction chamber is 1580-1600 DEG C, and introducing C3H8 and SiH4 into the reaction chamber; placing liquid-state trimethyl aluminum into a bubbler as a doping source, introducing a certain amount of H2 into the bubbler and introducing the H2 into the reaction chamber along with the trimethyl aluminum.

Description

technical field [0001] The invention belongs to the technical field of semiconductor device manufacturing, and in particular relates to a method for preparing a P-type gradient doped silicon carbide epitaxial layer by utilizing the existing MOCVD growth process of silicon carbide material. Background technique [0002] Silicon carbide has the advantages of wide band gap, high thermal conductivity, high breakdown strength, high electron saturation drift velocity, high hardness, etc., and also has strong chemical stability. These excellent physical and electrical properties make silicon carbide have many advantages in application. The forbidden band allows silicon carbide intrinsic carriers to maintain a low concentration at high temperatures, so it can work at very high temperatures. The high breakdown field strength enables silicon carbide to withstand high electric field strength, which allows silicon carbide to be used to make high-voltage, high-power semiconductor device...

AI Technical Summary

Problems solved by technology

However, due to the high bond strength of silicon carbide, the doping in the device manufacturing process cannot use the diffusion process, and can only be controlled by epitaxy and high-temperature ion implantation.

High-temperature ion implantation will cause a lot of lattice damage and form a large number of lattice defects, which are difficult to completely eliminate even with annealing, seriously affecting the performance of the device, and the efficiency of ion implantation is very low, so it is not suitable for large-area doping

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