Method for improving channel mobility of SiC metal-oxide-semiconductor field-effect transistor (MOSFET)

Abstract

The embodiment of the invention relates to a method for improving the channel mobility of a SiC metal-oxide-semiconductor field-effect transistor (MOSFET). The method comprises the following steps: before gate-oxide is carried out, carrying out ultraviolet oxidation treatment on the epitaxy surface of SiC epitaxial wafer; carrying out rubisco activase (RCA) cleaning, and forming an Si interface structure on the epitaxy surface; carrying out plasma enhanced chemical vapor deposition (PECVD) pretreatment on the SiC epitaxial wafer in oxygen atmosphere, and oxidizing the Si interface structure of the epitaxy surface into an SiO2 interface layer; carrying out gate-oxide oxidizing deposition growth on the SiO2 interface layer by PECVD, and carrying out annealing; and preparing a polycrystalline silicon gate and source and drain metal electrodes, so as to form the SiC MOSFET.

Description

technical field [0001] The invention relates to the technical field of microelectronics, in particular to a method for improving SiC MOSFET channel mobility. Background technique [0002] SiC has become one of the most advantageous semiconductor materials for manufacturing high-temperature, high-power electronic devices due to its excellent physical, chemical and electrical properties, and has a power device quality factor much greater than that of Si materials. The research and development of SiC power device Metal-Oxide-Semiconductor Field-Effect Transistor (Metal-Oxide-Semiconductor Field-Effect Transistor, MOSFET) began in the 1990s. It has high input impedance, fast switching speed, high operating frequency, and high temperature and high pressure resistance. The advantages of the series have been widely used in switching regulated power supplies, high-frequency heating, automotive electronics, and power amplifiers. [0003] However, at present, the main material of the...

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Problems solved by technology

[0003] However, at present, the main material of the gate dielectric of SiC power MOS devices is SiO2 generated by thermal oxidation, but the quality of the contact interface between SiC and SiO2 is poor, and the high density of interface states and interface roughness lead to serious degradation of device channel mobility and on-resistance , even making the performance of SiC-based devices fall short of those of Si-based devices

Although the interface state can be partially reduced by introducing nitride components during the annealing process through process improvement, the problem of C atom complexes at the interface between SiC and SiO2 during the oxidation process cannot be fundamentally solved, which also makes the channel of SiC The mobility has been very low, seriously restricting the development of SiC power devices

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