Power semiconductor device and manufacturing method thereof

Abstract

The invention discloses a power semiconductor device and a manufacturing method thereof. The power semiconductor device comprises a semiconductor substrate; an epitaxial layer located on the semiconductor substrate; the first dielectric groove and the second dielectric groove are located in the epitaxial layer, and the first dielectric layer is filled in the first dielectric groove and the second dielectric groove; the gate oxide layer, the control gate and the shielding gate are located in the first dielectric groove; the source region and the drain region are located on the two sides of the first medium groove and the second medium groove; wherein the control gate extends from the surface of the epitaxial layer to the upper part of the first dielectric groove, the shield gate extends from the surface of the epitaxial layer to the lower part of the first dielectric groove, and the gate oxide layer separates the control gate from the shield gate and separates the control gate from the epitaxial layer. The structure of the two medium grooves is adopted, so that the drift region is not a straight line any more, the drift region with the broken line (V-shaped or concave) morphology is formed, the effective length of the drift region can be increased, and smaller characteristic on-resistance can be achieved under the same breakdown voltage.

Description

technical field [0001] The present invention relates to the technical field of semiconductor manufacturing, in particular to a power semiconductor device and a manufacturing method thereof. Background technique [0002] Power semiconductor devices are mainly used in high-power power supply circuits and control circuits, for example as switching elements or rectifier elements. Among power semiconductor devices, power MOS (field effect transistor) devices have become one of the mainstream power devices due to their advantages of high input impedance, low loss, fast switching speed, no secondary breakdown, and good dynamic performance. At present, high-voltage power MOS devices mainly include VDMOS (Vertical-double-diffused metal oxide semiconductor, vertical double-diffused metal oxide semiconductor) devices, and superjunction devices that appear on the basis of VDMOS. [0003] For the power MOS device industry, the industry pursues better cost performance, that is, better pe...

AI Technical Summary

Problems solved by technology

[0004] However, the RSP value of VDMOS devices is relatively large, the epitaxial layer is relatively thick, more furnace tube processes are required in the production process, resulting in low production efficiency, special terminal processing structures are required, resulting in larger chip areas, etc.

Super junction devices can achieve smaller RSP by using charge balance technology, but it brings higher process cost

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