AsGa+ antisites identified by electron spin resonance as a main interface defect system in thermal GaAs/native oxide structures

Abstract

Aiming to assess the atomic-structural identity of inherently generated interfacial point defects during thermal oxidation, a conventional low-temperature electron spin resonance study has been carried out on (100)GaAs/native oxide structures thermally grown in the range of 350–615 °C on both powders and slices of semi-insulating (100)GaAs. This compellingly reveals substantial generation (density ∼ 1 × 1013 cm−2) of interfacial 75AsGa+ antisites in registry with the GaAs substrate layer, thus providing solid independent evidence of substantial interfacial As enrichment, appearing as endemic to oxidation of GaAs, and at the same time, providing an answer of how a major part of excess As gets interfacially incorporated. Given the known electrical deep double donor attribute of AsGa, direct identification is thus established of a major system of detrimental interface traps.