Groove type field effect transistor structure and preparation method thereof

Abstract

The invention provides a groove type field effect transistor structure and a preparation method thereof. The preparation method comprises the steps: providing a substrate, forming an epitaxial layer, forming a device groove in the epitaxial layer, and forming a shielding dielectric layer, a shielding gate layer, a first isolation dielectric layer, a gate dielectric layer, a gate layer, a second isolation dielectric layer, a body region, a source electrode, a source electrode contact hole, a source electrode structure and a drain electrode structure. In the preparation process of the groove type field effect transistor structure, a self-alignment process is adopted, so that the pitch of a cell unit is not limited by the exposure capability of a photoetching machine and the alignment precision of the photoetching machine, the pitch of the cell unit of a device can be further reduced, the cell density is improved, the channel resistance of the device is reduced, and a device structure with stable electrical parameters and low characteristic on-resistance is obtained; by arranging a T-shaped source electrode structure, the contact area between a source electrode structure and a source and the contact area between the source electrode structure and the body region are increased, so that the contact resistance of the source can be effectively reduced, and the avalanche tolerance of the device is improved.

Description

technical field [0001] The invention relates to power semiconductor technology, in particular to a trench type field effect transistor structure and a preparation method thereof. Background technique [0002] Shielded gate trench MOSFET devices have the advantages of lower on-resistance and faster switching speed than traditional trench MOSFETs, and have a wide range of applications, including switching power supplies, AC-AC conversion, motor control, radio frequency communications, uninterruptible power supplies, Inverter and other fields. In order to obtain a high conversion efficiency application system, it is necessary to continuously reduce the switching loss and conduction loss of the shielded gate trench MOSFET. Reducing the conduction loss means reducing the characteristic on-resistance of the shielded gate trench MOSFET. [0003] Reducing the device cell size (Pitch) and increasing the cell density is the most effective way to reduce the characteristic on-resistanc...

AI Technical Summary

Problems solved by technology

[0005] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a trench type field effect transistor structure and its preparation method, which is used to solve the problem of complex device preparation process and difficulty in reducing the size of device cells in the prior art. And other issues

Images