Implantation profiles of ³²P channeled into silicon crystals

Abstract

Concentration profiles of 32 P ions implanted into silicon crystals have been studied over the energy range 10–110 keV, using an electromagnetic separator. Beam directions near the major channeling axes [Formula: see text] and [Formula: see text] were chosen. After implantation, the profiles were determined by the method of anodic stripping, and the beta activity of each oxide layer removed was measured in a low-background proportional counter. Concentration profiles were studied as a function of the ion energy, crystal orientation, crystal temperature, and ion dose. Precise crystal orientation was achieved by a proton-channeling technique making use of protons of around 10 MeV energy from the Harwell tandem generator. The maximum penetration of channeled ions along the [Formula: see text] axis was found to vary with the energy, E, approximately as E 0.6 . Significant temperature effects were observed, and the influence of radiation damage on ion channeling was studied and is related to other observations.