Investigatons on Initial Beta Drift During Reliability Test for MOCVD Grown C-doped InGaP/GaAs HBTs
Lance Rushing, Catherine Luo and Peter Zampardi
Skyworks Solutions Inc.,
Email: Catherine.Luo@Skyworksinc.com, Phone: 805-480-4553
Barbar Landini, Kevin Stevens, Charles Lutz and Roger Welser
Email: Roiger_Welser@Kopin.com, Phone: 508-824-6696
Keywords: HBT, reliability, beta burn-in, beta drift
We report on investigations of the initial drift in DC current gain, or beta (b), during the early stages of reliability testing of MOCVD-grown carbon doped InGaP/GaAs HBTs. The b drift is compared for different HBT structures with varying burn-in percentages. Competing mechanisms are observed in which b can either increase or decrease during the initial stages of reliability testing. This b drift behavior is found to depend upon both the b burn-in percentage and the hydrogen concentration in the base. Hydrogen-related defect mechanisms are found to adequately explain the observed b decreases, while non-hydrogen related recombination reduction mechanisms must be considered to account for the b increases observed during the initial stages of reliability testing.