A SELF-ALIGNED PATTERING METHOD BY USING NON-CONFORMAL FILM AND ETCH BACK FOR SONOS MEMORY

摘要

A method for fabricating a memory device with a self-aligned trap layer (1301, 1308) which is optimized for scaling is disclosed. In the present invention, a non-conformal film (1406, 1407) is deposited over the charge trapping layer (1104) to form a thick film on top of the core source/drain region (1302) and a pinch off (1111) and a void (1107) or a narrow channel (1112) at the top of the STI trench (1103). An etch is performed on the non-conformal film (1406, 1407) to open pinch-off (1111) or widen the narrow channel (1112) in the non-conformal (1406, 1407). The trapping layer (1104) is then completely or partially etched between the core cells. The non-conformal film (1406, 1407) is removed. And a top oxide is formed. The top oxide converts the remaining trap layer (1104) to oxide if the trapping layer (1104) is partially etched and thus isolate the trap layer.