Off-axis channeling disorder analysis

Abstract

A new method has been developed to obtain, by means of channeling measurements, the distribution of defects in a plane normal to a low‐index axis direction. This method takes advantage of the response of nonsubstitutional atoms to the spatial distribution of the channeled ion flux. It represents then an extention of the flux‐peaking effect used to locate foreign atoms in a single‐crystal lattice. This method has been used to study the disorder introduced by 300‐keV N⁺ implantations in Si with fluences ranging between 6×10¹⁴ and 10¹⁶ ions/cm² and analyzed in situ with 2.0‐MeV He⁺ backscattering. Flux distributions of channeled ions have been evaluated as a function of the impinging angle for the analysis of the experimental data indicates a departure from a uniform transverse distribution of scattering centers both along the 〈111〉 and the 〈110〉 directions for low damage levels. The analysis has been detailed together with the main assumptions, and the range of validity of the method has been defined.