Transient behavior of the kink effect in partially-depleted SOIMOSFET's

The behavior of transients in the drain current of partially-depleted (PD) SOI MOSFET's down to L_eff=0.2 μm is examined as a function of drain bias, gate pulses of varying magnitude (V_GS), pulse duration, and pulse frequency. At fixed V_DS, the gate is pulsed to values ranging from 0.1 V above V_T to V_GS=V_DS. A slow transient is seen when the drain is biased at a V_DS where the current kink is observable. This slow transient can be on the order of microseconds depending on the relative magnitude of the impact ionization rate. For short times after the pulse edge or for very short pulses at low frequencies, it is shown that the subthreshold drain current value can be very different from the corresponding DC, and that the kink characteristic of PD MOSFET's disappears. However, the kink values can be approached when the pulse frequency and/or duration applied to the gate is increased, due to the latent charge maintained in the floating body at higher frequencies. No transient current effects were observed in fully-depleted SOI MOSFET's