On the origin of periodic surface structure of laser-annealed semiconductors

Abstract

Observations on laser-irradiated GaAs are reported in which the phenomenon of induced surface periodicity is related to a nonlinear interaction between simultaneously oscillating axial modes of the laser. It is suggested that during surface melting and regrowth material is distributed along nodal lines of a standing acoustic wave pattern corresponding to the axial mode beat frequencies. The several patterns observed are not consistent with an interference effect at optical frequencies.