Method for improving doping uniformity among silicon carbide multilayer structure epitaxial material batches

Abstract

The invention relates to a method for improving doping uniformity among silicon carbide multilayer structure epitaxial material batches, which includes that a chemical vapor phase deposition growth technology serves as the base, pure silane and pure propane serve as growth sources, hydrogen gas serves as carrier gas and diluent gas, and nitrogen gas serves as a doping agent to achieve n-type dopping after a (0001) silicon surface carbonized silicon substrate which inclines to a direction (11-20) by 8 degrees is preprocessed. Nitrogen gas doping efficiency is increased by using low speed epitaxy method and combing carbon and silicon ratio at a low air inlet end, a thin epitaxial layer with high doping concentration is grown on the carbonized silicon substrate in an epitaxial mode by using lower nitrogen gas flow, when a high resistance thick layer epitaxy is grown, the C / Si ration at an air inlet end is increased, and channel layers with the needed concentration and thickness are grown by using high speed epitaxy method to reduce background memory effects. The method has the advantages that repeatability of epitaxy technique is improved, and technical support is provided for batch production of silicon carbide multilayer structure epitaxial materials and particularly Schottky diode structure epitaxial materials.

Description

technical field [0001] The invention proposes a method for improving the doping uniformity between batches of silicon carbide multilayer structure epitaxial materials, and improves the repeatability of the epitaxial process. It belongs to the technical field of semiconductor materials. Background technique [0002] Power electronics technology is the core technology in the field of energy and electric energy conversion. High-efficiency energy conversion is an important driving force for energy saving, environmental protection, and low-carbon economy. High-voltage and large-capacity power electronic devices for high-efficiency energy conversion are key components and foundations; long-term Silicon devices have been dominant in almost all applications of power electronic systems since the beginning; there is no doubt that mature process technology is the biggest advantage of silicon devices; however, the performance of silicon devices is close to the theoretical limit determin...

AI Technical Summary

Problems solved by technology

[0003] The epitaxial materials used in silicon carbide power electronic devices are generally composed of multi-layer epitaxial layers, such as silicon carbide Schottky barrier diode structure epitaxial materials, in order to ensure high blocking voltage, high-resistance thick-layer epitaxy is required, and at the same time, in order to alleviate N + Due to the lattice mismatch caused by the difference in doping concentration between the substrate and the high-resistance thick-layer epitaxy, a buffer layer needs to be added between the substrate and the high-resistance thick-layer epitaxy; at a high epitaxy rate, the required doping of the buffer layer can be achieved. It is necessary to increase the nitrogen flow rate, which will cause a strong background memory effect; under the same epitaxial process conditions, the doping concentration of the epitaxial material channel layer will gradually increase with the number of furnaces, resulting in batch-to-batch doping Concentration uniformity is reduced; if the memory effect is to be eliminated, a long time of baking is required, resulting in longer process time and lower production capacity

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