Boron localisation in silicon, an application of nuclear reaction channelling for materials analysis

Abstract

Boron trace concentrations of 100 ppm were localised in single crystalline and as-grown silicon by combining the channelling technique with nuclear reaction analysis (NRA). Angular scans were performed in the 〈100〉 and 〈110〉 directions on silicon, using the 11B(p, α)2α reaction with an incident proton energy of 700 keV. For the evaluation, the stopping power and ion flux distributions in the silicon crystal were simulated using the Monte Carlo code MABIC [1]. The projected boron concentrations of the two scans were used to calculate a three-dimensional impurity concentration distribution. Boron was found to be located substitutional, as well as on well-defined interstitial sites in the silicon crystal lattice.