GASB-OXIDE REMOVAL AND SURFACE PASSIVATION USING AN ELECTRON-CYCLOTRON RESONANCE HYDROGEN SOURCE

We describe the use of a low-temperature technique, which is based on H atoms from a microwave electron cyclotron resonance (ECR) H-2 plasma, to remove surface oxides and carbon from a single-crystal GaSb surface. Our experiments indicate that oxide removal occurs at a temperature of approximately 250-degrees-C, much lower than that for thermal evaporation of the oxide. In addition, we have found that subsequent exposure to N atoms from a N2 PlasMa leaves a thin nitride layer, which prevents degradation of the H-cleaned surface. To demonstrate this technique, we have applied it to the processing of an AlGaSb PIN photodiode, which is fabricated with molecular-beam epitaxy material. Our electrical measurements show that the leakage current, after surface Sb-oxide removal, is significantly reduced from that before the ECR-H treatment.