Semiconductor Device and Method of Forming High Voltage SOI Lateral Double Diffused MOSFET with Shallow Trench Insulator

摘要

A semiconductor device has a buried oxide layer formed over a substrate. An active silicon layer is formed over the buried oxide layer. A drain region is formed in the active silicon layer. An LDD drift region is formed in the active silicon layer adjacent to the drain region. The drift region has a graded doping distribution. A co-implant region is formed in the active silicon. A source region is formed in the co-implant region. A shallow trench insulator is formed along a top surface of the LDD drift region. The shallow trench isolator has a length less than the LDD drift region. The shallow trench insulator terminates under the polysilicon gate and within the LDD drift region. A polysilicon gate is formed above the active silicon layer between the source region and LDD drift region and at least partially overlapping the shallow trench insulator.