Effects of carbon content and annealing conditions, on the electrical activation of indium implanted silicon

Abstract

Several sets of lightly n-doped silicon wafers were implanted with indium at an energy of 70 keV and a dose. of 5.8 × 1014 cm-2. Carbon was subsequently co-implanted with an energy of 13.5 keV at doses ranging from 0 to 2.22×1015 cm-2 to achieve a carbon distribution overlapping the indium one with ratio of peak concentration ranging from 0 to 2. The samples were annealed at temperatures of 650 to 1100°C for times between 0 dwell and 1 hour in flowing N2. Following annealing electrical characterization of the samples was performed via four-point probe and Hall effect measurements to achieve information about sheet resistance (ρs), Hall mobility and sheet carrier concentration (NS). The retained dose and lattice site location of the In have been investigated using Rutherford backscattering spectrometry (RBS). Secondary Ion Mass Spectroscopy (SIMS) was performed to measure the atomic doping profiles in the samples. The results show that the electrical activation of the layer increases with increasing carbon concentration. Increasing the annealing temperature and/or time results in a deactivation of the implant.