LDMOS TRANSISTOR AND METHOD OF FORMING THE LDMOS TRANSISTOR WITH IMPROVED RDS*CGD

摘要

The Rds*Cgd figure of merit (FOM) of a laterally diffused metal oxide semiconductor (LDMOS) transistor is improved by forming the drain drift region with a number of dopant implants at a number of depths, and forming a step-shaped back gate region with a number of dopant implants at a number of depths to adjoin the drain drift region.

主权项

1. A laterally diffused metal oxide semiconductor (LDMOS) transistor comprising:
a semiconductor material; a drain drift region that lies within the semiconductor material, the drain drift region having a first conductivity type, a first horizontal dopant concentration peak at a first depth and a second horizontal dopant concentration peak at a second depth, the first depth being measured a distance down from a top surface of the semiconductor material, the second depth being measured a distance down from the first depth; a back gate region that lies within the semiconductor material to touch the drain drift region, the back gate region having a second conductivity type, a third horizontal dopant concentration peak at a third depth, a fourth horizontal dopant concentration peak at a fourth depth, and a fifth horizontal dopant concentration peak at a fifth depth, the third depth being measured a distance down from the top surface of the semiconductor material, the fourth depth being measured a distance down from the third depth, and the fifth depth being measured a distance down from the fourth depth; a gate dielectric layer that touches the top surface of the semiconductor material; and a gate that touches and lies over the gate dielectric layer directly over the drain drift region and the back gate region.