Patterning a surface on the nanometric scale by ion sputtering

Surface etching by ion sputtering, besides producing equilibrium-oriented p atterns similar to those obtained by molecular beam epitaxy (MBE), can also be used to pattern the surface along nonequilibrium orientations, thus ext ending the possibilities of MBE. By tuning the competition between ion eros ion at grazing angles and diffusion-induced surface reorganization, it is, for example, possible to pattern a substrate characterized by a square symm etry with a well-ordered ripple structure running along any desired directi on. (C) 1999 American Institute of Physics. [S0003-6951(99)03747-X].