Electrical and physical analysis of indium implanted (111) silicon

The physical and electrical properties of indium implanted (111) silicon have been investigated for the dose range 5×10¹²-5×10¹⁴ ion cm^-2. High resolution Rutherford backscattering and channeling with 2 MeV He ions were used for the physical analysis of samples, whilst the Hall effect technique, four point probe and current-voltage measurements on implanted resistor structures were employed for the electrical characterisation. The implantation induced disorder has been studied as a function of ion dose for low temperature and room temperature implants of 80 keV indium. The temperature dependence of the amorphous threshold dose is shown to be significant, despite the high mass of indium, and the experimental threshold is further shown to be in resonable agreement with existing theoretical models. For samples annealed at 823 K, the sheet resistivity, as a function of dose, exhibits a minimum at approximately 10¹⁴ ions cm^-2. We speculate that this can be explained in terms of the solid solubility on indium and the dependence of the carrier mobility on the amorphous layer regrowth mechanism. Rutherford backscattering data shows that the mechanism for regrowth is very sensitive to ion dose and anneal conditions.