Limits to solid solubility in ion implanted silicon

High resolution Rutherford backscattering and channeling has been employed to measure the substitutional solubility of Ar, As, In, Sb and Pb, implanted into (100) and (111) silicon. Results indicate that solid solubilities far exceeding maximum equilibrium values can be achieved in (100) implanted silicon via solid phase epitaxy during carefully controlled furnace annealing at temperatures below 600°C. Such behaviour has previously been observed only following pulsed laser or electron beam annealing. Intriguing redistribution effects have been observed for In and Pb implants which provide considerable insight into impurity trapping mechanisms operative during solid phase epitaxy. Preliminary measurements indicate a tendency for the implant species to come out of solution after subsequent annealing at 1000°C.