Hole tunneling from valence band and hot-carrier induced hysteresis effect in 0.13 μm partially depleted silicon-on-insulator n-MOSFETs

The hysteresis effect between forward and reverse drain-source voltage (VDS) sweeps in the transient output characteristics is studied in ultra-thin gate oxide floating-body partially depleted (PD) silicon-on-insulator (SOI) n-MOSFETs. In this study, two mechanisms including direct-tunneling and impact ionization are taken into account. The transient variation of the floating body potential during sweeps leads to the threshold voltage (VTH) unstable, hence the hysteresis delay occurs. It is proposed that hole tunneling from valence band (HVB) causes positive hysteresis at lower drain-source voltage (VDS) region, while impact ionization (II) induced floating body charging leads to opposite phenomenon at high VDS, thus causing threshold voltage unstable in drain bias switching. And our findings reveal that hysteresis effect can be a serious reliability issue in SOI devices with floating body configuration.