Patent ID: 6309940
Filing Date: 2001-10-30
Classification: H01L

Abstract:
A method of fabricating a semiconductor device comprising:forming a field oxide layer on a semiconductor substrate having a first conductivity type where the semiconductor substrate includes first and second MOS transistor regions and first and second contact regions;forming a first well having a second conductivity type in the semiconductor substrate, wherein the first well includes the first MOS transistor region and the first contact region;forming a heavily doped region of buried layer having the second conductivity type at a portion spaced corresponding to the first contact region in the first well;forming a second well having the first conductivity type in the semiconductor substrate, wherein the second well includes the second MOS transistor region and the second contact region; andforming a heavily doped region of buried layer having the first conductivity type at a portion spaced corresponding to the second contact region in the second well, wherein the heavily doped region of the second conductivity type does not extend under a first MOS transistor in the first well, and wherein the heavily doped region of the first conductivity type does not extend under a second MOS transistor in the second well.