Abnormal transconductance and transient effects in partially depleted SOI MOSFETs

A transconductance dip, observed in floating body partially depleted SOI devices, is due to transient effects 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 effects also cause an initial current ramp in I-DS-V-GS characteristics at the start of the gate voltage sweep when the back gate is inverted. The transient effect diminishes as the channel length and channel width decrease and as the back bias increases. (C) 1998 Elsevier Science Ltd. All rights reserved.