LOW-DAMAGE SURFACE-TREATMENT BY GAS CLUSTER-ION BEAMS

Low-damage irradiation effects of gas cluster-ion beams have been stud ied at acceleration voltages below 20 kV. The surfaces of targets have been smoothened significantly by CO2-cluster-ion irradiation at norma l incidence. Si substrate surfaces have been cleaned and exhibited low damage after CO2- and Ar-cluster-ion irradiation at low doses. In the case of CO2-cluster-ion irradiation, SiO2 film of about 5.5-nm thickn ess have grown on Si substrate at room temperature. A damaged layer of less than 2.5-nm thickness has been formed underneath the SiO2 film.