Trench type vertical double-diffused metal oxide transistor and manufacturing method thereof

Abstract

Disclosed is a manufacturing method of a trench type vertical double-diffused metal oxide transistor. The manufacturing method comprises the following steps of providing an N type substrate and forming an N type epitaxial layer, a P type body region and a trench in the N type substrate in sequence; forming a gate oxide layer and first polysilicon on the inner wall of the trench in sequence; forming second polysilicon on the gate oxide layer in the trench, the first polysilicon and the P type body region; performing heat treatment on the second polysilicon to enable N type impurities in the second polysilicon to enter the surface, adjacent to the polysilicon, of the P type body region so as to form an N type source region on the surface, adjacent to the second polysilicon, of the P type body region, wherein the second polysilicon on the outer side of the trench is oxidized into silicon dioxide on the N type source region; performing etching on silicon dioxide, the N type source region and the P type body region so as to form contact holes which run through silicon dioxide on the two sides of the trench and the N type source region and extend to the P type body region; and forming afront surface metal layer and back surface metal.

Description

【Technical field】 [0001] The invention relates to the technical field of semiconductor manufacturing technology, in particular to a trench-type vertical double-diffused metal oxide transistor and a manufacturing method thereof. 【Background technique】 [0002] The trench type VDMOS (vertical double diffused metal oxide transistor) is widely used in the field of switching power supply. Trench-type vertical double-diffused metal-oxide-semiconductor transistors (referred to as: trench-type VDMOS) are channeled by forming a vertical diffusion distance difference after source ion and bulk ion implantation, and are widely used in the field of switching power supply and synchronous rectification. Compared with the planar VDMOS, the internal resistance of the trench VDMOS is very small because the JFET area is eliminated. [0003] However, the existing trench-type VDMOS has problems such as relatively complicated process and high cost, which need to be improved. 【Content of invent...

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Problems solved by technology

[0003] However, the existing trench-type VDMOS has problems such as relatively complicated process and high cost, and it is necessary to improve

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