Heat of crystallization and melting point of amorphous silicon

Abstract

Thin layers of amorphous silicon (a-Si) were produced by noble gas ion implantation of (100) substrates held at 77 K. Rutherford backscattering and channeling, and differential scanning calorimetry were used to measure the heat of crystallization, ΔHac, to be 11.9±0.7 kJ/mol, substantially less than the value predicted by scaling ΔHac of a-Ge. The crystal growth velocity is found to have the form v=v0 exp(−2.24 eV/kT). We obtain a new estimate, 1420 K, for the melting temperature of a-Si.