A DHTOL Test-Based Methodology to Investigate the Switching Reliability of GaN HEMTs Under Repeated Drain Voltage Ringing

The dynamic high-temperature operating lifetime (DHTOL) test is used to validate the product level robustness of a device in interaction with other system components and various product operating modes. This article presents a DHTOL-based test methodology for investigating the switching reliability of gallium nitride high electron mobility transistors in applications involving large drain-to-source voltage ringing. To conduct this study, a highly scalable, modular and reconfigurable test bench architecture is presented that can simultaneously test multiple devices under realistic stress conditions. The test vehicles are designed to replicate the switching stress typical of a quasi-resonant flyback converter while optimizing overall power consumption. In addition, the setup includes features for inline dynamic <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$R_{DS,\text{ON}}$</tex-math></inline-formula> monitoring, enabling user-friendly tracking of the changes of this key parameter throughout the test duration. This real-time monitoring capability is highly beneficial for understanding and gaining valuable insights into the evolution of the devices’ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$R_{DS,\text{ON}}$</tex-math></inline-formula> under continuous stress conditions. Using a prototype of the proposed test bench, multiple samples from three different device vendors are stressed under two distinct test conditions each. All tests are conducted over an intended duration of 1000 h and a detailed description of the results observed is also presented in this article.