Reliability of submicron InGaAs/InP DHBT under thermal and electrical stresses

We report on the reliability of InGaAs/InP DHBT technology which has applications in very high-speed ICs (over 100 Gbits/s). This work presents the results of accelerated aging tests under thermal and electrical stresses performed on HBT up to 2000 h. Stress conditions consist in applying collector-emitter bias VCE from 1.3 to 2.7 V and collector current densities JC of 400 and 610 kA/cm2. The corresponding junction temperatures TJ extends from 83 to 137 °C. The base current ideality factor ηB increase and the current gain β decrease have revealed a degradation of the base-emitter junction. The normalized current gain βnorm drop has occurred earlier for higher VCE and/or higher TJ. A 20% decrease of βnorm chosen as the failure criterion leads to an activation energy of 1.1 eV.