Defect-induced nucleation and growth of amorphous silicon

We propose a microscopic model of the amorphization of silicon such as that resulting from ion implantation. We demonstrate that amorphization can be induced by the presence of defects provided they form clusters embedded in a defective crystalline matrix. Our results are in striking agreement with transmission-electron microscopy measurements and confirm the superlinear dependence of damage on deposited energy, supporting the view that the crystal-to-amorphous transition proceeds via nucleation and growth.