Hydrogen flow control N-type low-doped silicon carbide film epitaxial making method

Abstract

The invention relates to a hydrogen flow control N-type low-doped silicon carbide film epitaxial making method. The making method comprises the following steps: 1, placing a silicon carbide substrate in a reaction chamber of a silicon carbide CVD apparatus, and vacuumizing the reaction chamber; 2, introducing H2 to the reaction chamber until the pressure in the reaction chamber reaches 100mbar, maintaining the pressure in the reaction chamber unchanged, gradually increasing the H2 flow to 60L / min, and continuously introducing H2 to the reaction chamber; 3, starting 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 gradually rises to 1400DEG C; and 4, maintaining the temperature and the pressure unchanged when the temperature of the reaction chamber reaches 1580-1600DEG C, introducing C3H8 and SiH4 to the reaction chamber, introducing highly pure N2 to the reaction chamber as an N-type doping source, stopping the introduction of SiH4, C3H8 and highly pure N2 to the reaction chamber and maintaining for 1min after a first-layer N-type doping layer grows, reducing the H2 flow from 60L / min to 40L / min, and continuously introducing SiH4, C3H8 and the highly pure N2 to the reaction chamber to grow a second-layer N-type doping layer.

Description

technical field [0001] The invention belongs to the technical field of semiconductor device manufacturing, and in particular relates to a method for preparing an N-type gradient low-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 d...

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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