Double-trench sic MOSFET structure and manufacturing method for high-frequency applications

Abstract

The invention discloses a double-groove SiC MOSFET structure and a manufacturing method for high-frequency applications, wherein the double-groove SiC MOSFET structure is built on N ++ N on SiC substrate ‑ type SiC epitaxial layer, including: gate trench, source trench, N + Source region, P-type base region, P + shielded area, N-type current extension area, and N ‑ type epitaxial layer, where N + The source region and the P-type base region are arranged from top to bottom, P + The shielding area is located under the P-type base area and the source trench, and the N-type current expansion area is located in the P-type + Outside the shielded area, N ‑ The N-type epitaxial layer is located under the middle region of the bottom of the gate trench and the N-type current extension region. This structure not only has the excellent static quality factor of the traditional double-trench SiC MOSFET, but also can significantly reduce the switching loss and improve the short-circuit withstand capability.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a double-groove SiC MOSFET structure for high-frequency applications and a manufacturing method thereof. Background technique [0002] SiC is a typical third-generation semiconductor material. Compared with Si, it has a larger band gap, higher critical breakdown field strength and higher thermal conductivity. Therefore, compared with traditional Si-based power semiconductor devices, SiC-based power semiconductor devices can achieve high temperature, high voltage and high frequency operation, significantly improve system energy conversion efficiency, reduce system volume and improve system reliability. [0003] Although Si-based IGBT power devices have been widely used in industrial production and living equipment, they have obvious tail current, which increases switching loss on the one hand and limits the maximum operating frequency on the other hand. Therefore, it may b...

AI Technical Summary

Problems solved by technology

Although this double-trench structure can achieve a better compromise between breakdown voltage and on-resistance, the electric field at the bottom of the trench is still high, and there are still gate oxide reliability issues

At the same time, it also has high gate-to-drain capacitance, which will also reduce the switching speed of the device and increase switching loss, which is not conducive to high-frequency applications

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