Analysis of channel-width effects in 0.3 /spl mu/m ultra-thin SOI NMOSFETs

Experiment-based new phenomena, such as LIF energy and channel width effects in ultra-thin (T/sub Si/=700 /spl Aring/) 0.3 /spl mu/m SOI NMOSFETs, are analysed using TCAD tools. The relatively higher doping profile along with the width direction silicon edge can improve the breakdown characteristics (i.e., BV/spl cong/9 V at W/L=0.4 um/0.3 um). This effect, which does not coincide with typical BV characteristics in very-small SOIs, is caused by the reduction of the impact ionization rate due to the doping and geometric effects of the silicon edge as the channel-width becomes narrower. It implies that very small SOI NMOSFETs can be well adopted for the ultra-high density DRAM cells when an optimised doping profile is provided.