DC and microwave reliability of discrete GaAs HBT devices

This paper details the first direct comparison of DC and microwave reliability for GaAs Heterojunction Bipolar Transistor (HBT) devices. We use a two-temperature constant-stress lifetest with unbiased transistors. We project a median-time-to-failure (MTTF) of 9.7×10 ⁷ hours at 125°C with an activation energy of 1.56 eV, based on a failure criterion of 1 dB reduction of DC current gain, β. Our measurements indicate that the microwave properties degrade much more slowly. For a failure criterion of 1 dB reduction of |S₂₁ | at 5 GHz, we project an MTTF of 1.6×10¹⁰ hours with an activation energy of 1.92 eV. Our results confirm that these GaAs HBT devices are highly reliable for microwave applications