Structure for avalanche improvement of ultra high density trench mosfet

Abstract

A trench metal-oxide-semiconductor field-effect transistor (MOSFET) cell having a trenched gate surrounded by a source region between a body region disposed above a drain on the bottom surface of a substrate Inside. The MOSFET cell also has a source-body contact trench opened such that its sidewalls extend substantially perpendicular to the upper surface into the source and body region and are filled with contact metal plugs. forming a body-resistance reducing region doped with a body impurity to surround the source-body contact trench to reduce the body-region resistance between the source-body contact metal and the trench gate to improve avalanche ability.

Description

Technical field [0001] The present invention generally relates to the unit structure and manufacturing process of power semiconductor devices. In more detail, the present invention will introduce a new and improved cell structure and an improved manufacturing method for trench semiconductor power devices with improved avalanche capability. Background technique [0002] The traditional process of forming aluminum metal contacts between the N+ source and the P-well formed in the P base region in a semiconductor device will encounter technical difficulties with poor metal coverage and unreliable electrical contacts when the cell pitch is reduced. When the metal oxide semiconductor field effect transistor (MOSFET) cell density increases to 200 million cells per square inch (200M / in 2 ) Above, the cell pitch is reduced to 1.8 microns or even smaller, this technical difficulty is particularly significant. For the case where the cell density exceeds 200 million cells per square inch, th...

AI Technical Summary

Problems solved by technology

Therefore, for semiconductor devices such as MOSFETs, it is still difficult to achieve the design goal of increasing cell density while improving avalanche capability

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