A 4h-sic metal-semiconductor field-effect transistor with multiple recessed buffer layers

Abstract

The invention discloses a 4H-SiC MSFET with a multi-recess buffer layer, belongs to the technical field of field effect transistors, and aims at improving the breakdown voltage and transconductance parameter of the field effect transistor and improving a DC characteristic. The MSFET comprises a 4H-SiC semi-insulating substrate, a P type buffer layer and an N type trench layer from bottom to top, a source cap layer and a drain cap layer are arranged at the two sides of the N type trench layer respectively, a source electrode and a drain electrode are arranged in the surfaces of the source cap layer and the drain cap layer respectively, a gate electrode is formed on the N type trench layer at the side close to the source cap layer, the upper end surface of the buffer layer is provided with three buffer-layer recess regions respectively in positions under the gate electrode and a gate source, under a gate-drain at the side close to the gate electrode and under the gate-drain at the side close the drain cap layer, the depths of the three buffer-layer recess regions are all 0.15 micron, and the lengths of the three buffer-layer recess regions are 1.2, 0.1 and 0.5 microns respectively.

Description

technical field [0001] The invention belongs to the technical field of field effect transistors, in particular to a 4H-SiC metal-semiconductor field effect transistor with multiple recessed buffer layers. Background technique [0002] Silicon carbide (SiC) has attracted people's attention due to its excellent electrical properties such as wide band gap, high critical electric field, high saturation drift velocity and high thermal conductivity, and has become the third-generation semiconductor material. These excellent properties make silicon carbide (SiC) often used in working conditions such as high pressure, high temperature, high frequency, and high power. SiC plays a major role in the application of microwave power devices, especially metal semiconductor field effect transistors (MESFETs), and has become a research hotspot in the field of microwave power devices in recent years. [0003] Among power devices in the microwave frequency band, 4H-SiC MESFETs have extremely ...

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Problems solved by technology

[0005] Chinese patent (application number 201410181931.6) discloses 4H-SiC metal-semiconductor field effect transistor, but its structure has a great influence on the saturation leakage current while increasing the breakdown voltage

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