Comprehensive Reliability Investigation of the Voltage-, Temperature- and Device Geometry-Dependence of the Gate Degradation on state-of-the-art GaN-on-Si HEMTs

In this work, the gate degradation of GaN-based HEMTs is analyzed. We find that the gate degradation does not occur only beyond a critical voltage, but it has a strong voltage accelerated kinetics and a weak temperature dependence. By means of a statistical study we show that the time-to-failure can be fitted best with a Weibull distribution. By using the distribution parameters and a power law model it is possible to perform lifetime extrapolation based on the gate degradation at a defined failure level and temperature for the first time. From this elaboration, the lifetime of a given device geometry can also be extracted. Eventually, the strong bias dependence of the gate degradation reported here implies that this phenomenon should be assessed by means of a voltagebased accelerated investigation as described in this work.