Metal oxide semiconductor field effect transistor based on multi-grid structure and preparation method thereof

Abstract

The invention discloses a metal oxide semiconductor field effect transistor based on a multi-grid structure. The metal oxide semiconductor field effect transistor comprises an N-based P channel or P-based N channel substrate. A source electrode and a drain electrode are respectively led out of the two P+ regions of the N-based P channel substrate or the two N+ regions of the P-based N channel substrate. An oxide layer is arranged between the source electrode and the drain electrode. Multiple sub-grids are arranged on the oxide layer. The sub-grids are discretely arranged in a spacing way from the source electrode to the direction of the drain electrode so as to form the multi-grid structure, wherein each sub-grid comprises a polysilicon layer and an electrode layer which is arranged on the polysilicon layer. The substrate also comprises multiple doping regions which are the same type of the channel and arranged between the two P+ regions or the two N+ regions. Each doping region is corresponding to the position below the gap of the adjacent sub-grids in a one-to-one way. Compared with the conventional single grid structure, an electric field can be effectively scattered by multiple grids so that the phenomenon of collapse voltage caused by the strong electric field generated beside the grids can be suppressed. The invention also provides a preparation method of the transistor.

Description

technical field [0001] The invention relates to a semiconductor device, in particular to a metal-oxide-semiconductor field-effect transistor based on a multiple gate structure and a preparation method thereof. Background technique [0002] In the currently popular transistors, whether silicon (Si), silicon carbide (SiC) or gallium nitride (GaN) is used as a switching device, how to suppress gate The collapse phenomenon caused by the strong electric field generated by the high voltage is the subject of many research units. [0003] Metal Oxide Semiconductor Field Effect Transistor (MOSFET) is a field effect transistor widely used in analog circuits and digital circuits. According to the polarity of the channel, it is divided into two types: N-channel and P-channel. Taking the P-based N-channel enhanced type as an example, a P-type silicon semiconductor is used as a substrate, and two N+ regions are diffused on its surface, and then covered with a silicon oxide insulating lay...

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Problems solved by technology

[0004] At present, for a MOSFET with a planar structure, the amount of current it can withstand and the breakdown voltage are related to the length and width of its channel. Therefore, in circuit design, the distance between the gate and the drain is usually elongated to Increase the breakdown voltage, but its working current will also be relatively reduced, which is difficult to meet the actual use needs

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