The annealing behaviour of ion-implanted Si studied using time-resolved reflectivity

The annealing behaviour of ion-implanted Si has been studied using time-resolved reflectivity (TRR). Various regimes have been identified which depend upon the implanted species and dose, the substrate orientation and the annealing temperature. At low doses, electrically active impurities, such as Sb, enhance the regrowth rate in 〈100〉 orientated Si. In 〈111〉 Si, the presence of low concentrations of certain impurities, such as Sb, Ga and Sn, also affects the degree of twinning which accompanies epitaxial regrowth. At higher doses of impurities, the regrowth rate of 〈111〉 and 〈100〉 Si is retarded and some impurities are seen to segregate at the amorphous-crystalline interface. Further increasing the dose provokes a dramatic phase transition to fine grain polycrystalline Si for the low melting point impurities, occurring typically 250°C below temperatures where epitaxial crystallisation is observed.