The current-carrying corner inherent to trench isolation

Abstract

It is shown how the characteristics of the corner MOSFET inherent to trench isolation can be extracted from hardware measurements and how the corner device must be taken into account when extracting MOSFET channel characteristics. For NFETs it is found that the corner's threshold voltage, substrate sensitivity, and sensitivity to well doping are all smaller than the channel's. The results imply that for low-standby-power logic applications requiring high performance, it may become necessary to locally control the well doping at the corner. However, the corner's reduced substrate sensitivity and width independence can provide a significant advantage in a DRAM cell.