Excimer laser etching of GaAs, Al Ga As and CuInSe in x 1yx 2 chlorine atmosphere

We have studied laser-induced etching LIE.of GaAs and Al Ga As xs0.2, 0.66, 0.8.under chlorine atmosphere. x 1yx In addition, LIE, applied to CuInSe2 for the first time, was investigated with respect to surface damage production and surface roughness at various laser energy densities. It was found that the etch rates of Al Ga As are higher than that of x 1yx GaAs at the same fluence increasing almost linearly with laser fluence. However, the etch threshold for of Al Ga As 55 x 1yx mJrcm2.is lower than of GaAs 85 mJrcm2.. It could be observed that the background pressure of H2O and O2have no influence on the etch threshold of GaAs and Al Ga As during LIE with Cl as reactive gas. Etching of CuInSe shows a x 1yx 2 2 complex etch rate dependence suggesting a combination of chemical and physical processes at the surface. Raman scattering was used to show that the surface stoichiometry of CuInSe2 can be varied from In-rich to Cu-rich by changing different laser parameters. However, in all cases there is crystal damage near the surface of the substrate. q1998 Elsevier Science B.V.