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., 2427 W. Hillcrest Drive, Newbury Park, CA91320

Email:, Phone: 805-480-4553

Barbar Landini, Kevin Stevens, Charles Lutz and Roger Welser

Kopin Corporation, 695 Myles Standish Blvd, Taunton, MA  02780

Email:, 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.


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