Surface compositional changes of InP due to krypton ion bombardment

Abstract

AbstractSputtering of the (110) and (100) surfaces of InP by Kr+ ions resulted in a preferential loss of the phosphorus species leaving an In‐enriched surface. The equilibrium Kr+‐sputtered surface composition of InP was determined by means of Auger electron spectroscopy. The sputtered surface composition ratio was independent of crystal orientation and ion energy (between 0.5 and 5 keV). Owing to a lack of other experimental krypton sputtering data, the experimentally obtained surface composition ratios were compared to the Sigmund theory for preferential sputtering in the linear cascade regime. A comparison with the Sigmund spike model showed the absence of spike effects in this krypton ion energy regime. A reasonable agreement was obtained between the experimental results and the Sigmund predictions. There was a correlation between the angle of incidence of the bombarding Kr+ ions and the final surface composition: The preferential sputtering effect became less with increasing angle of incidence θi (measured from the surface normal). The results show that the ratio of the phosphorus to indium compositions, namely X/X ∝ (cos θi)−a with a ≃ 0.24, and where θi is the angle of incidence of the ion beam with respect to the sample normal. This result is explained in terms of a model using the angle dependence of the sputtering yield of the constituent elements.