ABSTRACT
We report the first fabrication of AlGaAs/GaAs HBTs using InGaAs layer as dry-etching stopper. Various HBTs with different location of the etch-stop layer were fabricated to examine the influence of emitter-periphery guardring thickness on surface recombination. We show that it is vital to control the thickness to optimum 50 nm by selective etching technique, when the emitter periphery recombination current can be effectively reduced. We also discuss the current suppression effect caused by charge accumulation in the InGaAs quantum well. Simulation suggests that the undesirable side-effects can be minimized by appropriate epitaxial layer design.
