Surface Smoothing and etching by gas cluster ion beam

Abstract

Ar and CO2 gas cluster ion beam with a few nm size were generated by an adiabatic expansion through Laval nozzle. The existence and the mean size distribution of the cluster were analyzed by time‐of‐flight measurement. Crater induced by Ar cluster ion beam and crown‐like hillock by CO2 cluster ion impact on Si(100) were observed by an atomic force microcopy. CO2 cluster ion was irradiated on Si at 25 kV with the variations of ion dose from 1010 to 1013 cluster ions(CI)/cm2, at the flux of 109/cm2 s. Through this isolated cluster ion impact, the interaction mechanism between cluster ion with solid surface was suggested to be made of three steps: surface embossment, surface sputtering and smoothing, and surface etching. Another surface smoothing and etching experiment using CO2 cluster ion beam were carried out over ITO/glass and Cr‐masked Si3N4 thin film surfaces at 25 kV.