High-voltage shielding gate MOSFET with floating island structure and manufacturing method

Abstract

The invention relates to the technical field of semiconductor device manufacturing, in particular to a high-voltage shielding gate MOSFET with a floating island structure and a manufacturing method. The high-voltage shielding gate MOSFET with a floating island structure includes a semiconductor substrate. The semiconductor substrate includes an N-type substrate and an epitaxial layer growing on the N-type substrate. The epitaxial layer includes a lower epitaxial layer and an upper epitaxial layer growing on the lower epitaxial layer. The lower epitaxial layer is provided with a P-type floatingisland region. The upper epitaxial layer is provided with a groove which extends from a first main surface to a second main surface. The upper part of the groove is a gate region, the lower part of the grove is a shielding gate region, and the gate region and the shielding gate region are isolated by an oxide layer. The gate region is provided with a gate layer and a gate oxide layer. The shielding gate region is provided with a shielding gate layer and a shielding gate oxide layer. High withstand voltage can be achieved, and the on resistance can be greatly reduced because of the adoption ofthe low-resistance lower epitaxial layer.

Description

technical field [0001] The invention relates to the technical field of manufacturing semiconductor devices, in particular to a high-voltage shielded gate MOSFET with a floating island structure and a manufacturing method. Background technique [0002] Shielded gate MOS is based on traditional trench gate MOS, using thick oxide layer and discrete shielded gate to achieve lateral auxiliary depletion, so that lower resistance epitaxy can be used to achieve high withstand voltage requirements and reduce on-resistance. [0003] For general low-voltage shielded gate MOSFETs (such as <100V), low-resistance single epitaxy can be directly used to achieve withstand voltage; but for high-voltage shielded gate MOSFETs (such as 100V-300V), double epitaxy is often required to increase the withstand voltage, and the lower epitaxy The resistivity is much higher than that of the upper epitaxy, which will greatly increase the on-resistance. Since the on-resistance and the breakdown voltag...

AI Technical Summary

Problems solved by technology

[0003] For general low-voltage shielded gate MOSFETs (such as <100V), low-resistance single epitaxy can be directly used to achieve withstand voltage; but for high-voltage shielded gate MOSFETs (such as 100V-300V), double epitaxy is often required to increase the withstand voltage, and the lower epitaxy The resistivity is much higher than that of the upper epitaxy, which will greatly increase the on-resistance

Since the on-resistance and the breakdown voltage are in a contradictory relationship or a compromise relationship, that is, the reduction of the on-resistance is limited by the breakdown voltage, but the means of reducing the on-resistance usually used in the prior art will also limit the endurance Compression capacity

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