Charge Collection Mechanisms of Ge-Channel Bulk $p$ MOSFETs

Single-event transients in SiGe MOS devices with ultrathin quantum well channels have been shown in previous work to exhibit opposite polarities for source and drain strikes. This work reports polarity reversal in similar devices with thick Ge channels due to the favorability of prompt hole collection by either the source or drain region, depending on the strike location. A slower charge-collection mechanism is also present due to the
$n$
-well/
$p$
-substrate structure, which allows ion-generated carriers from the substrate to flood the body of the device.