Orientation dependence of laser amorphization of crystal Si

Abstract

Conditions for laser amorphization of Si were studied as a function of orientation for samples from [110] surface normal through [111] to [001] at 5\ifmmode^\circ\else\textdegree\fi{} intervals. Two regimes of behavior are observed, one within 15\ifmmode^\circ\else\textdegree\fi{} of [111] and a second for the remaining orientations. The transition energy density for amorphous crystal regrowth and the maximum a-Si thickness changes abruptly between regimes. These results are inconsistent with a single-ledge growth model and suggest that two separate interface morphologies or solidification mechanisms are active in the liquid-phase growth of Si.