A 4h-sic metal-semiconductor field-effect transistor with local low doping under the gate

Abstract

The invention discloses a 4H-SiC metal semiconductor field effect transistor having under-gate local low doping. The 4H-SiC metal semiconductor field effect transistor having under-gate local low doping is characterized by including a 4H-SiC semi-insulating substrate, a P buffer layer, and N-channel layer from bottom to top, the two side surfaces of the N-type channel layer are provided with a source cap layer and a drain cap layer, a surface of the source cap layer and the drain cap layer is provided with a source electrode, a drain electrode is arranged on the surface of the drain cap layer,a gate electrode is arranged at the bottom of the channel of the N-type channel layer and near the side of the source cap layer, a low doping layer symmetrical to the center of the gate electrode isarranged at the bottom of the N-type channel layer and below the gate electrode, and the bottom of the gate electrode is in close contact with the upper end of the low doping layer. Compared with theprior art, the breakdown voltage of the field effect transistor of the invention is improved, thereby improving the output power density of the device.

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 local low doping under the gate. 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-SiCMESFET has a very large ...

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Problems solved by technology

However, due to the limitations of the traditional device structure, the device is limited by the balance of saturation leakage current and breakdown voltage. Under the condition of ensuring a large breakdown voltage of the device, it is necessary to sacrifice the saturation leakage current related to the device in exchange for a larger breakdown voltage.

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