Patent ID: 7919347
Filing Date: 2011-04-05
Classification: H01L

Abstract:
1. A method of fabricating a diode, comprising the steps of: (a) forming an opening in a hardmask layer on a top surface of a silicon substrate; (b) forming a trench in said silicon substrate in said opening; (c) forming a doped region of a first dopant type in said substrate, said doped region abutting sidewalls and a bottom of said trench; (d) growing an intrinsic epitaxial silicon layer on said sidewalls and said bottom of said trench, said intrinsic epitaxial silicon later not completely filling said trench; (e) depositing a doped polysilicon layer after (d) to fill remaining space in said trench, said doped polysilicon layer doped a second dopant type, said second dopant type different from said first dopant type; (f) performing a chemical mechanical polish, after said chemical-mechanical-polish, top surfaces of said intrinsic epitaxial silicon layer and said doped polysilicon layer and said hardmask layer are coplanar; (g) forming, after (f), a dielectric isolation layer in said substrate, said isolation layer completely covering said doped region intrinsic epitaxial silicon layer, and a less than whole portion of said doped polysilicon layer and not covering a second less than whole portion of said doped polysilicon layer, after said forming said isolation layer, a new top surface of said doped region and a new top surface of said intrinsic epitaxial silicon layer are coplanar; (h) forming a dielectric layer on top of said isolation layer and said second less than whole portion of said doped polysilicon layer not covered by said isolation layer; and (i) forming, after(h), a first metal contact to said doped polysilicon layer and a second contact to said doped region, said first contact extending from a top surface of said dielectric layer to said top surface of said doped polysilicon layer, said second contact extending from a top surface of said dielectric layer, through said isolation layer to said new top surface of said doped region.