Low-energy mass-selected ion beam production of fragments produced from hexamethyldisiloxane for the formation of silicon oxide film

Fragment ions produced from hexamethyldisiloxane (HMDSO) with a hot tungsten wire in a Freeman-type ion source were studied using a low-energy mass-selected ion beam system. The mass numbers of the fragment ions were identified. Although the chemical formulae of these fragments were not completely identified yet, the possible candidates of dominant fragment ions were H+, H2+, H3+, C+, CH3+, O+, Si+, C3H3+, SiO+, SiC2+, SiOCH2+, SiC3H9+, Si2OCH3+, Si2OC2H7+, Si2OC3H9+, Si2OC4H11+, and Si2OC5H15+. The rates of ion fragment production strongly depended on the tungsten temperature. Among those fragment ions, SiO+ ions were mass-selected. The ion energy was approximately 50 eV. Then, the SiO+ ions were irradiated to substrates and resulting deposited films were analyzed. Following the completion of the ion irradiation experiment, X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy measurements of the films demonstrated the occurrence of silicon oxide deposition. We conclude that the irradiation of the mass-selected SiO+ ions, obtained from HMDSO, to substrates is useful for the secure growth of silicon oxide films.