A multi-exciton model for the electronic sputtering of oxides

Three models are examined for the electronic sputtering by high energy heavy ions. It is found that the charged fraction of the sputtered particles is small (less than 10% in this study) and hence, Coulomb explosion model is unsound. According to the thermal spike model, rapid thermal quenching of the melted zone is anticipated, implying amorphisation of SiO2 single crystal (c-SiO2). X-ray diffraction results indicate no amorphisation of c-SiO2, suggesting no melting. Moreover, the electronic sputtering yields of both c-SiO2 and amorphous-SiO2 (a-SiO2) have been found to be the same. With these results and thermal properties of both c-SiO2 and a-SiO2, thermal spike model is examined further and appears to be unfavorable. A multi-exciton model is suggested for the electronic sputtering.