Power metal oxide semiconductor field-effect transistor and manufacturing method thereof

Abstract

The invention relates to a power metal oxide semiconductor field-effect transistor and a manufacturing method thereof, wherein the power metal oxide semiconductor field-effect transistor comprises a substrate, an epitaxial layer, a body region, a source region, a grid electrode, a grid insulating layer, a contact hole and a heavily doped region, wherein the substrate has a first conduction type; the epitaxial layer is positioned on the substrate, has the first conduction type, and has a concentration lower than the doping concentration of the substrate; the body region is positioned on the epitaxial layer and has a second conduction type; the source region is positioned on the body region, has high doping concentration, and has the first conduction type; the grid electrode passes through the source region and the body region and arrives at the epitaxial layer; the grid insulating layer is arranged on the surface of the grid electrode; the contact hole passes through the source region and arrives at the body region; an inward depressed part is formed at the bottom of the contact hole; and the heavily doped region with the second conduction type is arranged on and only on the outside surface of the inward depressed part. In the invention, the adopted contact hole structure is provided with a vertical side wall and the inward depressed bottom part, thereby reducing and even avoiding avalanche breakdown, and improving the product stability.

Description

technical field [0001] The invention relates to a semiconductor device, especially a power metal oxide semiconductor field effect transistor and a manufacturing method thereof. Background technique [0002] Because the power metal oxide semiconductor field effect transistor (power MOSFET) has the characteristics of low power and fast switching speed, and when it is working in forward bias, the majority of carriers are conductive so that it is generally considered that there is no secondary breakdown phenomenon, and the power MOSFETs are widely used in switching devices for power supplies. [0003] However, when the power MOSFET is reverse-biased, avalanche breakdown is prone to occur inside the power MOSFET due to the effects of drain-source voltage and current. refer to figure 1 , in the equivalent circuit in the power MOSFET body, a parasitic triode 110 is included between its source and drain, the collector and emitter of the parasitic triode 110 are respectively the dr...

AI Technical Summary

Problems solved by technology

Therefore, on the surface of the U-shaped groove, due to the concentration of the electric field and the large reverse current density, it is easy to cause avalanche breakdown.

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