Formation of Periodical Surface Ripple in Laser-Assisted Etching of GaAs

Abstract

The formation of the periodical surface ripple of GaAs in laser-assited photochemical etchingusing the 4th harmonics of a Nd: YAG laser (wavelength: 266nm) was studied. The surface rippleswere aligned in the direction of the projected polarization of incident laser light on the surface. Thus, the ripples are resulted from the interference of the surface plasma waves (SPW) and the incident laser light. The wavenumber of the SPW excited by s-polarization was 2.76×10⁵cm^-1 which is close to a calculated value of 2.37×10⁵cm^-1. In the case of p-polarization, thewavenumber of the ripple is nearly equal to that of SPW added by the surface component of the wavenumber, k₀sinθ=0.23×10⁵cm^-1.