Multistage super junction structure and self-alignment preparation method thereof

Abstract

The invention relates to a multistage super junction structure and a self-alignment preparation method thereof. The multi-stage super junction structure comprises an epitaxial layer and a multi-stage super junction column region, the multi-stage super junction column region comprises a plurality of single-stage column regions, the plurality of single-stage column regions correspond to a plurality of single-stage grooves, and the self-alignment preparation method of the multi-stage super junction structure comprises the following steps: growing a surface etching mask and forming a groove side wall protection layer for multiple times, and using the surface etching mask and the trench side wall protection layer to perform multiple times of self-alignment etching to form a multi-stage trench. According to the multistage super junction structure and the self-alignment preparation method thereof provided by the invention, the inclination angle of the side wall of the super junction groove can be regulated and controlled, and the influence caused by a side etching effect during deep groove etching can be effectively reduced in a manner of forming the side wall protection layer of the groove and then performing multistage etching; therefore, the super-junction deep groove is kept relatively high in perpendicularity, and the performance of a super-junction device is improved.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a multilevel super junction structure and a self-alignment preparation method thereof. Background technique [0002] In recent years, more and more attention has been paid to energy saving and emission reduction in the world, which puts forward higher requirements for loss control and efficiency improvement of large power electronic equipment. As an important part of power electronic equipment, semiconductor power devices have received extensive attention from the industry. Super junction devices can break through the one-dimensional theoretical performance limit of ordinary devices, and have great performance advantages and application potential in the medium and high voltage fields. [0003] The current mainstream super junction device manufacturing technology route includes multiple epitaxy and trench epitaxy backfilling processes. Among them, the super junction devic...

AI Technical Summary

Problems solved by technology

For silicon carbide materials, the etching options under non-metallic masks are relatively low, and it is difficult to etch super-junction deep trenches. How to etch deep trenches with high aspect ratio and controllable sidewall inclination angles has become a challenge for this type of process. difficulty

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