A kind of tmos gate structure and its forming method

Abstract

The invention provides a method for forming a TMOS gate structure, comprising: providing a semiconductor substrate to roughen the surface of the semiconductor substrate; etching the semiconductor substrate to form trenches; and sequentially forming a gate oxide layer on the semiconductor substrate And the polysilicon layer, the thickness of the gate oxide layer formed outside the trench is larger than the thickness of the gate oxide layer formed in the trench; the polysilicon layer is removed by chemical mechanical polishing, and only the polysilicon layer remaining in the trench is used as the TMOS gate . The invention also provides a TMOS gate structure corresponding to the method for forming the TMOS gate structure. In the method for forming the TMOS gate structure provided by the present invention, the thickness of the gate oxide layer formed outside the trench is greater than that of the gate oxide layer formed inside the trench, so the gate oxide layer formed outside the trench and close to the trench Although the gate oxide layer is prone to wear and tear, the increase in thickness does not cause leakage of the device, which ensures the normal performance of the device.

Description

technical field [0001] The invention relates to the technical field of semiconductor manufacturing, in particular to a TMOS gate structure and a forming method thereof. Background technique [0002] Due to the development of power semiconductor devices, many electronic devices have become smaller and smaller with a corresponding increase in efficiency. As one of the main bodies of power semiconductor devices, power MOSFETs are widely used in communications, computers, automobiles and consumer electronics, and are an important part of discrete devices and smart power integrated circuits (SPIC). An ideal power MOSFET should be able to withstand a large blocking voltage in the off state, have a small forward voltage drop in the on state, and have a large current handling capability and a faster switching speed, thereby reducing its switching loss. However, in the actual design, its various indicators must be taken into account, thus limiting the power MOSFET to reach the idea...

AI Technical Summary

Problems solved by technology

[0005] The technical problem to be solved by the present invention is to provide a TMOS gate structure and its formation method to solve the problem that the gate oxide layer in the non-trench area close to the sidewall of the trench easily leads to loss and leakage

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