Metal semiconductor field effect transistor with wide-channel deep sags

Abstract

The invention belongs to the technical field of field effect transistors, and especially discloses a metal semiconductor field effect transistor with wide-channel deep sags. The invention aims to provide a metal semiconductor field effect transistor with wide-channel deep sags which has higher output current and breakdown voltage and better frequency characteristic. The technical scheme adopted is as follows: a 4h-SiC half-insulating substrate, a P-type buffer layer and an N-type channel layer are arranged from top to bottom; a source cap layer and a drain cap layer are respectively arranged at the two sides of the N-type channel layer; a gate electrode is arranged in the middle of the N-type channel layer and close to the side where the source cap layer is arranged; the gate electrode enables a left channel sag area and a right channel sag area to be formed at the two sides of the N-type channel layer; the depths of the left channel sag area and the right channel sag area are 0.15-0.25 microns; the width of the left channel sag area is 0.5 microns, and the width of the right channel sag area is 1 micron; and a high-gate area is formed between the channel surface and the gate electrode.

Description

Technical field: [0001] The invention belongs to the technical field of field effect transistors, and particularly relates to a metal semiconductor field effect transistor with a wide channel and a deep recess. Background technique: [0002] SiC material has outstanding material and electrical characteristics such as wide band gap, high breakdown electric field, high saturated electron migration speed, high thermal conductivity, etc., making it suitable for high frequency and high power device applications, especially high temperature, high pressure, aerospace, satellite, etc. There is great potential in the application of high frequency and high power devices in harsh environments. In the SiC allomorphs, the electron mobility of the hexagonal close-packed wurtzite structure of 4H-SiC is nearly three times that of 6H-SiC. Therefore, 4H-SiC materials are used in high-frequency and high-power devices, especially in metal semiconductor fields. Effect transistor (MESFET) occupies a ...

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Problems solved by technology

[0004] Although the breakdown voltage of the double-recess structure 4H-SiC MESFET is increased due to the fact that half the length of the source side of the gate is recessed into the N-type channel layer, the saturation leakage current has not been substantially improved.

And in practice, the process of reactive ion etching (RIE) will form lattice damage on the surface of the drift region of the device, resulting in a decrease in the effective mobility of carriers in the N-type channel layer, thereby reducing the drain current. In terms of current output characteristics manifested as a degradation of the saturation current

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