θ= 135 orientation of the tilt angle with respect to the direction of the electron wind is very critical for the development of the surface topography. The preset edge-void perturbation on the surface becomes unstable immediately after turning on the electric field. At first the Gaussian shape edge-void transform into a wedge having sharp edge on the windward side, and later the formation of oscillatory wave on the lee and windward sides appears with deceasing in amplitude in space. The wedge shape edge-void finally ejects a small but rounded internal void to the bulk region, and it disappears completely at the background oscillatory waves. These surface undulations continue to spread all along the surface in both directions. This phenomenon occurs regardless the intensity of the electron wind as long as χ≥ 1, below which it may be stabilized because of the predominating effect of the capillary forces over the electron winds.