Enhanced Gate Stack Reliability Test Framework for Gan Hemt in High-Stress Environments Leveraging on Ramp and Constant Voltage Stress Protocols

This study proposes an enhanced reliability testing framework for GaN transistors, utilizing two distinct reliability test protocols. The first protocol, a successive multi-stage compliance ramp voltage sweep (MSCRVS), incrementally increases the voltage to the gate breakdown threshold with varying current compliance, allowing a detailed analysis of failure progression in GaN devices. MSC-RVS enables modeling of the physics of failure mechanisms as functions of temperature and voltage through stage-specific electrical and physical failure analysis. The second protocol employs a constant voltage stress (CVS) scheme, applying fixed current compliance while varying voltage levels. CVS testing under different voltage and temperature conditions supports parameter fitting of the physics of failure models, calibration, and subsequent device lifetime predictions (extrapolation). This study, conducted at room temperature, highlights a multimodal failure mechanism within the device, revealing different regions susceptible to degradation. Three primary failure regions were identified: Schottky, Passivation, and PiN, each associated with unique failure modes: (A) Schottky-only breakdown, (B) Schottky with passivation breakdown, and (C) combined Schottky with PiN/passivation breakdown. The findings provide valuable insights into the multimodal failure pathways in p-GaN gate HEMTs, advancing the understanding of their reliability under varied stress conditions.