Patent ID: 9502547
Filing Date: 2016-11-22
CPC Classification: H01L

Claim Text:
1. A method for forming an IGBT device, comprising: forming one or more trenches for trench gates in a substrate including a bottom semiconductor layer of a first conductivity type and an upper semiconductor layer of a second conductivity type located above the bottom semiconductor layer, wherein each of the one or more trenches is provided with a gate insulator on each side of the trench and filled with polysilicon and wherein the trench extends vertically into the upper semiconductor layer; forming a floating body region of the first conductivity type between two neighboring trenches and over the substrate, wherein a bottom of the floating body region is close in depth to but above a bottom of the polysilicon in the trench; forming a top region of the second conductivity type over the floating body region, wherein the top region of the second conductivity type is heavily doped; and forming a body region of the first conductivity type over the top region, wherein the body region extends from one of the two neighboring trenches to the other of the two neighboring trenches, wherein a doping concentration of the floating body region of the first conductivity type is lower than that of the body region of the first conductivity type; and forming a heavily doped source region of the second conductivity type disposed over the body region of the first conductivity type and proximate a sidewall of each of the one or more trenches.