HYDROCARBON-BASED ETCHING OF INP

We used X-ray (AlKalpha) and soft X-ray (ZrMzeta) photoelectron spectroscopy to investigate some fundamental mechanisms of hydrocarbon-based etching of InP(100). In order to differentiate chemical and energetic aspects we applied two different techniques of sample treatment, the hot-filament technique and ion bombardment. In both cases, exposure to hydrogen, methane, or their mixtures, resulted in a preferential loss of phosphorus relative to indium; simultaneously, metallic indium was formed; in addition, oxygen-related species are removed in all cases. The carbon contamination only diminishes under application of the hot-filament technique; whereas methane-ion bombardment increases the carbon concentration drastically with increasing exposure. This latter behaviour is assigned to the implantation of carbon-related species into the InP lattice, the increase in linewidth of the P 2p, In 4d, and C Is core levels corroborates this. In contrast, the filament-activated processes exhibit no changes in linewidth.