Method for reducing 4H-SiC intrinsic deep energy level defects

Abstract

The invention discloses a method for reducing 4H-SiC intrinsic deep energy level defects, which can be used for improvement on 4H-SiC material quality and application to devices. The particular process is as follows: (1) a 4H-SiC substrate is pretreated, and an N<-> extension layer grows on the front surface of the 4H-SiC substrate; (2) a layer of SiO2 is deposited on the N<-> extension layer and taken as a blocking layer for carbon ion injection; (3) the carbon ion injection with different energies and dosages is preformed for three times on the surface of the blocking layer; and (4) the 4H-SiC sample wafer after the three times of carbon ion injection is subjected to RCA cleaning and drying, and then annealing in a high-temperature environment in the presence of hydrogen and silane, the injected carbon ions are activated, and the treatment to the intrinsic deep energy level defects of the 4H-SiC material is completed. The actual measurement shows that the invention can effectively reduce the deep energy level defects in the 4H-SiC sample wafer, and can be used for improving the quality of the 4H-SiC material and promoting the performance of devices.

Description

technical field [0001] The invention belongs to the technical field of microelectronic materials and devices, and in particular relates to a method for reducing intrinsic deep-level defects in 4H-SiC through a carbon ion implantation annealing process, which can be used for improving the quality of 4H-SiC materials and application of devices. Background technique [0002] As a third-generation semiconductor material, SiC material has considerable advantages over the first-generation semiconductor materials represented by Si and the second-generation semiconductor materials represented by GaAs. Due to its large forbidden band width, it can be used in Working at a higher temperature is conducive to the preparation of high-power devices, and the large carrier saturation drift speed and mobility provide a good foundation for the response speed of the device. At present, the development of SiC devices has become a research hotspot in the field of semiconductor device circuits. ...

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Problems solved by technology

According to the above theoretical analysis, it is proposed that high temperature annealing suppresses and reduces intrinsic deep level defects in 4H-SiC, but due to the lack of consideration of the time, temperature and surface protection of high temperature annealing, a series of problems such as Si precipitation on the surface of 4H-SiC are caused; The method of online growth to increase the flow rate of propane has also been proposed to suppress the generation of carbon vacancies, but deep-level defects are determined by various factors such as temperature and cooling rate, and only considering increasing propane cannot effectively reduce deep-level defects. On the contrary, it will affect the quality of 4H-SiC single crystal, such as crystal quality, surface roughness, etc.

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