Successful Surface Passivation of Air-Exposed AlGaAs by a Silicon Interface Control Layer-Based Technique

In order to make the silicon interface control layer (Si ICL)-based surface passivation technique applicable to air-exposed AlGaAs surfaces, various surface treatments were systematically studied. The treatments investigated include UHV thermal cleaning, ( NH4)2 S x treatment, HCl treatment and H2 plasma treatment. Chemical status and quality of the treated surfaces were evaluated by in-situ and ex-situ X-ray photoelectron spectroscopy (XPS) and photoluminescence (PL) measurements. A strong correlation was found between the band-edge PL intensity and the amount of surface oxide components, in particular Al-oxides. Marked reduction of the amount of oxide components and enhancement of PL intensity were realizable by a combination of HCl surface treatment and Si ICL formation.