Structural relaxation and order in ion-implanted Si and Ge

Abstract

Raman scattering measurements are reported as a function of annealing temperature on heavily damaged, ion-implanted Ge and Si. Changes in the opticlike, TO Raman bandwidth of amorphous Ge are found to correlate with the estimated heat of structural relaxation obtained from the data of Donovan et al. This result is consistent with a bond-strain model, demonstrating that structural relaxation is primarily associated with short-range bond-angle ordering. The results also allow an estimate of the temperature dependence of the width of the bond-angle distribution to be obtained with annealing. The Raman spectra of ion-implanted Si indicate greater order in the amorphous state than similarly prepared amorphous Ge. Estimates of the corresponding heat of structural relaxation of amorphous Si suggest that this should be observable.