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

　　Solid-State Electronics Volume 52, Issue 7, July 2008, Pages 1088-1091

　　Authors：Z. Jin ,  X. Liu, W. Prost and F.-J. Tegude

　　Abstract

　　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.