Shield gate mosfet and method for fabricating the same

Abstract

A shield gate MOSFET includes an epitaxial layer having a first conductivity type, a plurality of trenches in the epitaxial layer, a shield gate disposed in the trenches, a control gate on the shield gate in the trenches, an insulating layer between the shield gate and the epitaxial layer, a gate oxide layer between the control gate and the epitaxial layer, an inter-gate oxide layer between the shield gate and the control gate, a first doped region in the epitaxial layer at the bottom of the trenches, and a second doped region between the bottom of the trenches and the first doped region. The first doped region has a second conductivity type, and the second doped region has the first conductivity type, and thus the leakage path may be reduced in the presence of the second doped region so as to improve breakdown voltage.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This application claims the priority benefit of Taiwan application serial no. 108125082, filed on Jul. 16, 2019. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.BACKGROUNDTechnical Field[0002]The disclosure relates to a semiconductor structure and a method for fabricating the same, and more particularly, to a shield gate MOSFET and a method for fabricating the same.Description of Related Art[0003]The shield gate MOSFET is an improved structure of the trench gate MOS structure. Compared with the conventional MOS structure, the shield gate MOSFET may effectively reduce the capacitance of the gate to the drain (Cgd), thereby improving switching loss. With advancements in terminal consumer products, there is still a great need in related industries for novel semiconductor structures that may further improve the performance of various components.[0004]Howeve...

AI Technical Summary

Benefits of technology

The disclosure describes a new type of MOSFET that can improve the breakdown voltage. This is achieved by creating two regions in the epitaxial layer, one with a different conductivity type and another with the same conductivity type. The first region helps to create a uniform field distribution, while the second region reduces leakage pathways, resulting in a higher breakdown voltage.

Problems solved by technology

However, as components get smaller and operating voltage is increased, there is a need to seek a technical solution to increase component breakdown voltage.

Images