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

The propagation of surface ripples during Ga ion beam erosion of Si was measured in real time by combining focused ion beam technology with scanning electron microscopy. By detecting the secondary electrons emitted during implantation the surface was monitored in situ during the erosion. The ripple wavelength increases with the erosion time as lambdaproportional tot(0.50(4)). The value of the ripple velocity was observed to agree qualitatively with the results of Monte-Carlo simulations of the erosion process, and was found to decrease with the ripple dimension like nuproportional tolambda(x)(-1.5(1)).