Prompt Shift of On-State Resistance in LDMOS Devices: Causes, Recovery, and Reliability Implications

The present study reveals the occurrence of a sudden initial parameter shift, frequently referred as prompt shift, of the on-resistance due to operation points with high current flow during readouts. The shift is found to be partly recoverable, with recovery occurring on a logarithmic timescale. Additionally, the temperature behavior of the shift is observed to be similar to classical hot carrier injection (HCI), while its recovery is shown to diverge from classical bias temperature instability (BTI) recovery. These observations carry significant implications for the reproducibility of on-state resistance measurements and lifetime evaluation. Therefore, it is necessary to account for the immediate shift in on-state resistance measurements, which can be accurately predicted through a simple model proposed in this study, in order to conduct proper evaluation and get reliable and reproducible readouts.