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 (V_DS) 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 (V_TH) unstable, hence the hysteresis delay occurs. It is proposed that hole tunneling from valence band (HVB) causes positive hysteresis at lower drain-source voltage (V_DS) region, while impact ionization (II) induced floating body charging leads to opposite phenomenon at high V_DS, 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.