3 Factor Accelerated Lifetime Testing in Lateral GaN Power HEMTs: A Tutorial

This work introduces a novel accelerated lifetime testing (ALT) methodology for Lateral GaN-on-Si high electron mobility transistors (HEMTs) called “Three Factor Acceleration Testing.” By introducing 2DEG density (Ns) as a third acceleration factor, this method enables accurate characterization of the Lateral Gate-Drain failure mode while avoiding the Vertical buffer breakdown failure mode that often dominates at high voltages. To validate this method, intentionally fabricated “weak” parts with increased Ns were used to accelerate the Lateral Failure mode under reasonable voltage and temperature conditions. Time-to-failure experiments confirmed that the same Lateral Failure mode was dominant across a wide range of Ns values. Acceleration factors were extracted for temperature, voltage, and the new third variable Ns. From these acceleration factors a lifetime model was built which can predict the operational lifespan of our GaN HEMT under specific operating conditions. This methodology provides a more accurate and reliable framework for lifetime prediction, ensuring that reliability assessments better reflect real-world operation. By adopting this approach, the industry can significantly improve the accuracy of lifetime modeling in GaN-on-Si HEMTs, reducing the risk of unexpected field failures.