Patent ID: 8114745

Claim:
A method of forming a semiconductor device, the method comprising: providing a semiconductor substrate; forming a first well of the first conductivity type near a surface of the semiconductor substrate; forming a second well of a second conductivity type near the surface of the semiconductor substrate, the first well and the second well being separated by a first distance; forming a first transistor having a first source/drain region formed in the first well and a second source/drain region formed in the second well, a first portion of the substrate below the first source/drain region having a same conductivity type as the first source/drain region, a second portion of the substrate below the second source/drain region having a conductivity type opposite of the second source/drain region; forming a first isolation structure in the semiconductor substrate between the first source/drain region and the second source/drain region; and forming a second isolation structure in the second well, the second isolation structure being on an opposing side of the second source/drain region from the first isolation structure, the second well extending completely under the second isolation structure.