Device Design of SONOS Flash Memory Cell with Saddle Type Channel Structure

摘要

Saddle-type SONOS flash memory device with recess channel and side-gate was proposed and designed in terms of recess depth, doping profile, and side-gate length for sub-50 nm flash memory technology. The key features of the devices were characterized through 3-dimensional device simulation. This cell structure can store 2-bit or more in a cell when it is applied to NOR flash memory. It was shown that channel doping profile needs to be different depending on application (NOR or NAND). In NOR flash memory application, the localized channel doping under the source/drain junction is very important in designing V{sub}(th) and suppression of DIBL. Although this cell structure was very useful in NOR flash memory application, we also studied device design of the cell for NAND flash application.