Patent ID: 9666666
Date: 2017-05-30
CPC Classifications: H01L

Claim:
1. A method of manufacturing an insulated gate bipolar transistor (IGBT) device comprising: preparing a semiconductor substrate with an epitaxial layer of a first conductivity type supported on the semiconductor substrate of a second conductivity type; applying a gate trench mask to open a first trench and second trench followed by forming a gate insulation layer to pad the trench and filling the trench with a polysilicon layer to form the first trench gate and the second trench gate; implanting dopants of the first conductivity type to form an upper heavily doped region in the epitaxial layer; and forming a planar gate on top of the first trench gate and apply implanting masks to implant body dopants and source dopants to form a body region and a source region near a top surface of the semiconductor substrate; and implanting through the second trench to form a floating buried ring below a trench bottom surface of the second trench gate.