Patent ID: 8273627

Claim:
A semiconductor device comprising: two trenches formed in a semiconductor substrate, wherein each side surface of the two trenches is sloped; a charge storage layer as an insulator formed on each of the sloped side surfaces of the two trenches, wherein each sloped side surface of the two trenches has a separate charge storage layer, wherein the charge storage layers are separated from each other by the bottom surfaces of the two trenches, and wherein each charge storage layer extends substantially an entire length of a corresponding sloped side surface; and a bit line formed only below the bottom surface of each one of the two trenches inside the semiconductor substrate, wherein the bit lines are separated from respective side surface edges of each of the two trenches, wherein a channel region is formed in the semiconductor substrate from one side surface of one of the two trenches to that of the other trench via an upper surface of a protruding portion formed between the two trenches.