new data have been generated to aid in the prediction of device reliability The first requirement under a wide variety of electrical and for a better power thermal stress conditions. Two of the most sensitive areas for acceleration transistor is lower stresses are 1) stresses to the drain on-resistance. and source terminals at different voltages and temperatures and 2) stresses GaN Reliability to the gate and source terminals at Even with uniformly superior electridifferent voltages and temperatures. cal, thermal, and mechanical characThese will be examined in the next two sections in detail. teristics, a designer cannot use a new device, especially one that uses a completely different technology, unless there is convincing evidence that the product will work reliably in Drain-Source Acceleration the application. In addition to extensive qualification inforThe dominant failure mechanism of GaN transistors of all mation on GaN transistors from different producers [3], [6], types under high-temperature reverse bias (HTRB) stress is MOSFETs. By the end of 2016, as the cost of growing the thin GaN crystal layer on top of silicon comes down due to higher utilization of the existing commercial equipment, the cost equation will uniformly favor GaN. 0 13 MTTF Versus VDS and Temperature 10100 V 90 °C 0.50 1080 0.25 MTTF (s) 0V 12 V 11 0.10 100 Probability of Failure 0.75 Weibull Plots for RDS(on) Failure (150 °C) 0V 0.99 0.96 0.90 1020 EPC2016C 100 1020 1040 TTF (s) (a) 1060 1020 0.01% FIT Rate (number/109 h) 1025 1% 1020 0.0001% 1010 20 years 105 90 100 110 120 Drain Voltage (VDS) (b) 130 140 fig 5 (a) The representative Weibull plots for R DS^onh failures under HTRB stress. (b) The TTF versus drain voltage. The 20-year line is indicated by the green horizontal line. IEEE PowEr ElEctronIcs MagazInE 100 100 110 120 Drain Voltage (VDS) (a) z March 2015 130 140 FIT Rate Versus VDS and Temperature 1 FIT 10-20 35 °C 10-40 10-60 150 °C 90 °C 10-80 80 EPC2016C 100 80 90 1080 TTF Versus VDS(on) (150 °C) 1030 1015 Ten Year Line 100 80 0.01 TTF (s) 35 °C 1040 0.05 0.02 48 150 °C 1060 90 100 110 120 Drain Voltage (VDS) (b) 130 140 fig 6 (a) The MTTF versus drain voltage and temperature during HTRB stress (EPC2001C). The dashed green line indicates ten years. (b) The FIT rate versus VDS and temperature (EPC2001C). Units are expressed in number of failures per billion device-operating hours.