A kind of fabrication method of 4h-sic metal-semiconductor field-effect transistor with partially sunken channel

Abstract

The invention discloses a 4H-SiC metal semiconductor field effect transistor having a partial sinking channel. The 4H-SiC metal semiconductor field effect transistor having a partial sinking channel, from the bottom to the top, comprises a 4H-SiC half insulation substrate, a P type buffer layer, and an N type channel layer; the N type channel layer surface is provided with a source electrode cap layer and a drain electrode cap layer; the surfaces of the source electrode cap layer and the drain electrode cap layer are provided with a source electrode and a drain electrode; a grating electrode is formed above the N type channel layer and close to one side of the source electrode cap layer; part of the grating electrode close to the source electrode cap layer concaves downwardly to form a concave grating structure; a concave grating drain drifting area is formed between the grating electrode and the drain electrode cap layer; a concave grating drain buffer layer is formed on the upper end surface of a P buffer layer and close to the portion between the drain electrode cap layer and the concave grating drain side; and the concave depth of the concave grating drain drifting area is identical to that of the concave grating drain buffer layer. The 4H-SIC metal semiconductor field effect transistor having a partial sinking channel has advantages that the drain electrode is big in output current, the breakdown voltage is high and frequency characteristic is good.

Description

technical field [0001] The invention relates to the technical field of field effect transistors, in particular to a 4H-SiC metal semiconductor field effect transistor with a partially sunken channel. Background technique [0002] SiC materials have excellent electrical properties, including wide bandgap [(2.3~3.3)eV], high breakdown electric field [(0.8~3.0)×10 6 V / cm], high saturation drift velocity (2×10 7 V / cm) and high thermal conductivity (4.9Wcm -1 K -1 ), these characteristics can make SiC devices work under special conditions of high temperature, high power and high frequency. A notable feature of SiC materials is homogeneous polytype. Among all SiC polytypes, 4H-SiC with hexagonal close-packed wurtzite structure has received a high degree of attention, because the electron mobility of 4H-SiC structure It is about twice as much as 6H-SiC. Therefore, 4H-SiC materials occupy a dominant position in high-frequency high-power devices, especially metal-semiconductor f...

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Problems solved by technology

[0004] Compared with the traditional structure, although the saturation leakage current of the double-recessed 4H-SiC MESFET structure has been improved due to the increase of the channel thickness on both sides of the gate electrode, the breakdown voltage of the device has been greatly suppressed. decline

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