Ripple propagation and velocity dispersion on ion-beam-eroded silicon surfaces

Lehrstuhl fu ¨r Angewandte Festkorperphysik, Ruhr-Universita¨t Bochum, Universitatsstr. 150, D-44780 Bochum, Germany~Received 19 March 2001; revised manuscript received 4 September 2001; published 8 March 2002!The propagation of surface ripples during Ga ion beam erosion of Si was measured in real time by com-bining focused ion beam technology with scanning electron microscopy. By detecting the secondary electronsemitted during implantation the surface was monitored in situ during the erosion. The ripple wavelengthincreases with the erosion time as l}t