Patent ID: 8389341
Filing Date: 2013-03-05
Classification: H01L

Abstract:
1. A method comprising: performing an implantation to form a pre-high-voltage well (pre-HVW) in a semiconductor substrate, wherein the pre-HVW is of a first conductivity type; forming a high-voltage well (HVW) over and in contact with the pre-HVW, wherein the HVW is of the first conductivity type, and wherein the HVW has a higher impurity concentration than the pre-HVW; performing an implantation to form a field ring in the HVW and occupying a top portion of the HVW, wherein the field ring is of a second conductivity type opposite the first conductivity type; forming an insulation region over and in contact with the field ring and a portion of the HVW; forming a gate electrode partially over the insulation region; forming a drain region in the HVW, wherein the drain region is of the first conductivity type; and wherein the HVW horizontally extends further toward the drain region than the pre-HVW; and forming a source region adjacent to, and on an opposite side of the gate electrode than the drain region.