Patent ID: 9214457
Filing Date: 2015-12-15
Classification: H01L

Abstract:
1. A method for forming a high voltage device and a low voltage device on a semiconductor substrate comprising: providing a semiconductor substrate of a first conductivity type; forming a deep buried implant region of a second conductivity type opposite to the first conductivity type on a top portion of the substrate in an area for the high voltage device; growing a first epitaxial layer of the first conductivity type on a top surface of the substrate, wherein forming the deep buried implant region includes diffusing first ions extending from a depth of the substrate to the top surface of the first epitaxial layer forming a deep buried lightly doped region and activating and diffusing second ions in a vicinity around an interface between the substrate and the first epitaxial layer forming a deep buried highly doped region surrounded by the deep buried lightly doped region; forming a buried implant region of the second conductivity type on a top portion of the first epitaxial layer in an area for the low voltage device; growing a second epitaxial layer of the second conductivity type on a top surface of the first epitaxial layer; forming a plurality of doped regions from a top surface of the second epitaxial layer in both the low voltage device area and the high voltage device area to form a low voltage device and a high voltage device respectively, with the dopant concentration of the first epitaxial layer being the same as the substrate, wherein the doping concentration of the deep buried lightly doped region is the same as the second epitaxial layer.