Characterization and TCAD Modeling of Mixed-Mode Stress Induced by Impact Ionization in Scaled SiGe HBTs

Abstract

We investigate the reliability of state-of-the-art SiGe HBTs in 55-nm technology under mixed-mode stress. We perform electrical characterization and implement a TCAD model calibrated on the measurement data to describe the increased base current degradation at different collector-base voltages. We introduce a simple and self-consistent simulation methodology that links the observed degradation trend to interface traps generation at the emitter/base spacer oxide ascribed to hot holes generated by impact ionization in the collector/base depletion region. This effectively circumvents the limitations of commercial TCAD tools that do not allow impact ionization to be the driving force of the degradation. The approach accounts for self-heating and electric fields distribution allowing to reproduce measurement data including the deviation from the power-law behavior.

Characteristics and Degradation Mechanisms under High Reverse Base–Collector Bias Stress in InGaAs/InP Double HBTs

“…Several research institutes have studied the reliability of HBTs under mixed-mode stress and reverse bias stress through experiments [7,8] and TCAD modeling [8,9]. Several researchers have reported the reliability studies of InP-based HBTs.…”