Abnormal transconductance and transient eects in partially depleted SOI MOSFETs

A transconductance dip, observed in floating body partially depleted SOI devices, is due to transient eects and is reduced with a positive back bias in SOI nMOSFETs. MEDICI simulations show that both hole and electron densities near the front interface fluctuate during the turn-on transient, causing a small decrease and then an increase of the drain current that leads to the transconductance dip. Transient eects also cause an initial current ramp in IDS–VGS characteristics at the start of the gate voltage sweep when the back gate is inverted. The transient eect diminishes as the channel length and channel width decrease and as the back bias increases. # 1998 Elsevier Science Ltd. All rights reserved. 1