Patent ID: 6114723
Filing Date: 2000-09-05
Classification: H01L

Abstract:
A split gate flash memory cell comprising:(i) a floating gate and a poly oxide layer on top of said floating gate, both being etched to have a common reentrant angle such that the width of said poly oxide layer and said floating gate generally increases with increased distance from a substrate, and both said poly oxide layer and said floating gate have a sharp corner;(ii) an oxide sidewall spacer formed around a sidewall of said floating gate and said poly oxide layer, said oxide sidewall spacer being generally parallel to said reentrant angle, said oxide sidewall spacer being different from said poly oxide layer so as to allow said poly oxide layer to maintain a sharp corner;(iii) a nitride sidewall spacer formed around said oxide sidewall spacer, said nitride sidewall spacer also being generally parallel to said reentrant angle.