GaAs was etched in Cl@sub 2@/H@sub 2@/Ar plasmas both with ion and electron enhancement. Since bombardment with higher energy ions induces structural damage, electron bombardment and low-energy ion bombardment were used to prevent etch-induced damage. Damage was checked with XRD which shows peak broadening after etching when structural damage is induced on a surface or in a sub-surface layer. XRD peak broadening was seen in high-energy ion bombardment, but not in electron or low-energy ion bombardment. In order to study the competition between the thermal reaction and the electron enhanced reaction, temperature and bias for samples were varied as etching parameters. SEM images and AFM images were obtained and compared for the samples etched at different conditions. Under the damage-free etchig conditions morphology development was followed by measuring etch rate, surface roughness, skewness, and autocorrelation function (ACF) for surface roughness. The evolution of ACF was interpreted by scaling theory. Chemical and bombardment effects were explained based on the scaling theory. Morophological evolution steps and a key effect that determines surface morphology during etching were revealed from this study, and a way to control surface smoothness during dry etching was found.