Effect of ion sputtering on the statistical properties of a surface

The modification of a gallium arsenide surface during irradiation by heavy cesium ions Cs+ is investigated by measuring the surface height distributio n with an atomic force microscope. Both increases and decreases in the rms height sigma, an integral parameter of the surface, are observed to occur. It is established that for all experimental samples the roughness of the ga llium arsenide surface increases in a 1- 100 nm lateral range. Analysis of the structure function yields an estimate of the characteristic lateral dim ensions of the surface structures arising during ion etching. (C) 1999 Amer ican Institute of Physics.