Pseudo-MOSFET Drain-Current Transients: Influence of the Substrate

The pseudo-MOSFET drain-current transient time is used to determine the generation/recombination lifetimes of SOI wafers. We have analyzed this transient for p-films on p-substrates experimentally and through simulation and show the substrate, not the Si film, to dominate this transient. For negative-substrate-voltage pulses, the substrate is driven into deep depletion, and electron-hole pair generation influences the film potential and, subsequently, the drain current.