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 100Gbits/s). This work presents the results of accelerated aging tests under thermal and electrical stresses performed on HBT up to 2000h. Stress conditions consist in applying collector–emitter bias VCE from 1.3 to 2.7V and collector current densities JC of 400 and 610kA/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 1.1eV.