The surface recombination behavior of a series of InAlAs/InGaAsSb/InGaAs heterojunction bipolar transistors (HBTs) is investigated. It is found that the InGaAsSb base HBTs have lower emitter periphery surface recombination current density (K(SURF)) than the HBT with an InGaAs base. It is attributed to the type-I band lineup at the B-E junction and the surface pining of the antimonide base layer. A lower S(0) is deduced for the DHBT with a higher Sb content in the InGaAsSb base.
