Manufacturing method for trench-type power semiconductor

Abstract

The invention provides a manufacturing method for a trench-type power semiconductor, which comprises the following steps: firstly, providing a substrate, and defining a drain region in the substrate; then, forming a gate trench in the substrate; subsequently, forming a dielectric layer covering the inner surface of the gate trench; then, forming a clearance wall in the gate trench, wherein the clearance wall covers the dielectric layer located on the side wall of the gate trench; then, forming a plug structure at the bottom part of the gate trench, wherein the plug structure is located in a space defined by the clearance wall; then, removing the redundant clearance wall by utilizing the dielectric layer and the plug structure as masking; subsequently, removing the redundant dielectric layer by utilizing the etched clearance wall as the masking to enable the inner surface of the upper section of the gate trench to be bared outside; then, keeping the etched clearance wall, and directly forming a gate dielectric layer covering the inner surface of the upper section of the gate trench; and subsequently, forming a gate polycrystalline silicon structure in the upper section of the gate trench.

Description

technical field [0001] The invention relates to a method for manufacturing a trench type power semiconductor, in particular to a method for manufacturing a trench type power semiconductor structure with low gate charge. Background technique [0002] Compared with the traditional planar power semiconductor, the conduction current flows along the direction parallel to the surface of the substrate, while the trench power semiconductor sets the gate in the trench to change the position of the gate channel, so that the conduction Current flows in a direction perpendicular to the substrate. Therefore, the size of the components can be reduced, and the integration of the components can be improved. Common power semiconductors include metal oxide semiconductor field effect transistors (MOSFETs), insulated gate bipolar transistors (IGBTs), and the like. [0003] The main energy loss of power semiconductors during operation includes conduction loss from on-resistance and switching l...

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Problems solved by technology

As the frequency of operation increases, the

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