Separation methods for semiconductor charge accumulation layers and structures thereof

Abstract

Devices and methods for isolating adjacent charge accumulation layers in a semiconductor device are disclosed. In one embodiment, a semiconductor device comprises a bit line formed in a semiconductor substrate, a charge accumulation layer formed on the semiconductor substrate, a word line formed on the charge accumulation layer across the bit line, and a channel region formed in the semiconductor substrate below the word line and between the bit line and its adjacent bit line. For the semiconductor device, the charge accumulation layer is formed above the channel region in a widthwise direction of the word line, and a width of the word line is set to be narrower than a distance between an end of the channel region and a central part of the channel region in a lengthwise direction of the word line.