Explosive crystallization of ion-implanted silicon layers

Abstract

The autocatalytic or explosive mode of the phase transition amorphous-crystalline is due to the positive feedback of the released latent heat to the kinetics in the transition region accelerating the decay of the amorphous phase. It is shown experimentally that this process can be realized not only on SOI-structures but also in implanted amorphous layers on crystalline silicon substrate. The velocity of the explosive crystallization front was measured and the resulting structure of the layer was investigated to find out the influence of the implanted species and of the subjacent crystal. From the stationary solution of the heat-flow-control problem for the lateral movement of a thin molten zone in the amorphous layer the conditions for spreading of the explosive front over large distances are derived. Experimental and theoretical values are in good agreement. It is found that the lateral proceeding crystallization is governed by the substrate induced nucleation in the liquid interlayer, if a sharp interface between amorphous layer and the crystalline matrix is produced by solid phase epitaxy from the bulk.