Interface instability and cell formation in ion-implanted and laser-annealed silicon

Abstract

The phenomenon of solid-liquid interface instability during directional solidification has been studied in In+, Ga+, Fe+, and Sb+ implanted silicon after pulsed laser annealing. Interface instability results in lateral segregation which leads to the formation of cellular structures. The cellular structures have been studied using transmission electron microscopy. The critical bulk solute concentration above which instability develops, and the wavelength of instability (cell size) as a function of velocity of solidification have been calculated following the perturbation theory originally developed by Mullins and Sekerka. A good agreement between the experimental results and the calculations is obtained when the dependence of the interfacial distribution coefficient on the velocity of solidification is taken into account in the calculations.