Manufacture of lateral semiconductor devices

Abstract

A method of manufacturing a lateral semiconductor device comprising a semiconductor body (2) having top and bottom major surfaces (2a, 2b), the body including a drain drift region (6a) of a first conductivity type. The method includes the steps of forming a vertical access trench (20) in the semiconductor body which extends from its top major surface (2a) and has a bottom and sidewalls; forming at least one horizontal trench (16) extending within the drain drift region (6a) which extends from a sidewall of the vertical trench (20) in the finished device; and forming a RESURF inducing structure (22) extending within the at least one horizontal trench. In this way, vertically separated lateral RESURF inducing structures are formed without encountering problems associated with known techniques for forming RESURF structures.

Description

Technical field [0001] The present invention relates to methods of manufacturing lateral semiconductor devices, such as insulated gate field effect power transistors (commonly referred to as "MOSFETs"). The present invention also relates to a semiconductor device manufactured by this method. Background technique [0002] Lateral semiconductor devices are mainly used in integrated circuits and not in vertical devices, because the connection to the drain region of the lateral device can be made directly at the top surface of the semiconductor body. In contrast, in a vertical device, the drain region is typically formed at the bottom of the structure, and a separate peripheral contact region extending from the surface to the depth of the buried drain region must be provided, thereby substantially increasing the overall conduction of the device Resistance and complicate the manufacture of the device. [0003] The breakdown voltage of a simple p-n junction depends on the doping level ...

AI Technical Summary

Problems solved by technology

In contrast, in vertical devices, the drain region is typically formed at the bottom of the structure, and a separate perimeter contact region must be provided extending from the surface to the depth of the buried drain region, thereby substantially increasing the overall conduction of the device. resistance and complicates fabrication of the device

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