Method for preparing P-type lightly-doped silicon carbide thin film epitaxy by controlling hydrogen flow

Abstract

The invention relates to a method for preparing a P-type lightly-doped silicon carbide thin film epitaxy by controlling hydrogen flow. 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 vacuumizing the reaction chamber; (2) introducing H2 into the reaction chamber till the air pressure of the reaction chamber reaches 100 mbar, keeping the air pressure of the reaction chamber constant, then gradually increasing the H2 flow to 60 L / minute, and continuously introducing the H2 into the reaction chamber; (3) starting a high-frequency coil induction heater RF, greatly enhancing the power of the high-frequency coil induction heater RF, and etching in situ when the temperature of the reaction chamber is gradually increased to 1400 DEG C; and (4) when the temperature of the reaction chamber reaches 1580-1600 DEG C, keeping the temperature and pressure constant, introducing C3H8 and SiH4 into the reaction chamber, placing liquid trimethyl aluminum used as a doped source into a bubbler, and introducing a certain amount of H2 into the bubbler so that the H2 carried with the trimethyl aluminum is introduced into the reaction chamber.

Description

technical field [0001] The invention belongs to the technical field of semiconductor device manufacture, and in particular relates to a method for preparing a P-type gradient low-doped silicon carbide epitaxial layer by using 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 devices....

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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