Surface-recombination-free InGaAs/InP HBTs and the base contact recombination

In: Solid-State Electronics, Jg. Vol. 52 (2008) ; No. 7, S. 1088-1091
ISSN: 0038-1101
Zeitschriftenaufsatz / Fach: Elektrotechnik
Surface-recombination-free InGaAs/InP HBTs with graded base have been demonstrated. The HBTs were passivated by ammonium sulfide. The current gain of the nonself-aligned HBTs was independent of the emitter periphery, indicating that the surface recombination was removed by the  passivation. For the self-aligned HBTs, the current gain was still dependent on the emitter periphery after the passivation due to the base contact recombination. A surface leakage channel has been identified to result in a significant increase in the base contact recombination. The passivation has two effects: one is the surface  recombination velocity reduction and the other is the surface leakage channel elimination.