Reduction of surface recombination in InGaAs/InP heterostructures using UV-irradiation and ozone

In this paper we report the effects of dielectric films, hydrofluoric acid (HF) chemical treatments and UV-ozone on InGaAs/InP heterostructures. To ev aluate the passivation efficacy of these treatments, the heterojunction bip olar transistor (HBT) was chosen as a test vehicle, due to its sensitivity to surface recombination effects. We show that a surface treatment consisti ng of UV-ozone followed by HF etching allows plasma-enhanced chemical vapor deposition to be used to deposit a protective layer for InGaAs/InP HBTs wi thout degrading the electrical characteristics. This approach leads to bett er stoichiometry of the semiconductor surface following the UV-ozone treatm ent. Compared with untreated HBTs, the UV-ozone/HF treated devices shown lo wer base leakage currents and consequently less low frequency noise.