Patent ID: 7449737
Filing Date: 2008-11-11
Classification: H01L

Abstract:
1. An integrated circuit comprising: a photodiode formed in a semiconductor substrate and including an upper pn junction comprising a buried semiconductor region having a first type of conductivity and an overlying surface layer having a second type of conductivity; a transfer transistor associated with the photodiode comprising an insulated gate; and lateral spacers for the insulated gate at least one of which overlies a lateral surface extension portion of the overlying surface layer having the second type of conductivity; wherein the lateral surface extension portion has a first constant thickness extending for a first distance underneath the at least one lateral spacer; wherein the overlying surface layer further has a second constant thickness extending for a second distance outside the lateral spacer; and wherein the buried semiconductor region of the photodiode is also a source region for the transfer transistor, and further wherein the buried semiconductor region does not contact an insulating layer associated with the insulated gate.