Critical regime for amorphization of ion implanted silicon

Abstract

A critical regime has been identified for ion implanted silicon where only slight changes in temperature can dramatically affect the levels of residual damage. In this regime decreases of only 5° C are sufficient to induce a crystalline-to-amorphous transformation in material which only exhibited the build-up of extended defects at higher temperatures. Traditional models of damage accumulation and amorphization have proven inapplicable to this regime which exists whenever dynamic defect annealing and damage production are closely balanced. Irradiating ion flux, mass and fluence have all been shown to influence the temperature - which varies over a range of 300° C for ion species ranging from C to Xe - at which the anomalous behaviour occurs. The influence of ion fluence suggests that complex defect accumulation plays an important role in amorphization. Results are presented which further suggest that the process is nucleation limited in this critical regime.