Influence of the absorption coefficient in Nd laser annealing of amorphized semiconductor layers

Abstract

It is shown that epitaxial regrowth of thin amorphized Si layers by Nd‐laser irradiation is strongly affected by temperature‐induced changes in the absorptivity of the crystalline substrates. This results in an amplification of small spatial variations of the absorbed intensity by local thermal runaway. The problem can be avoided by either preheating the sample or by applying pulses of long duration and reduced intensity. A model explaining the observations is proposed.