Cross section measurements for electron-impact dissociation of SiF4 into neutral radicals

Abstract

Absolute cross sections for electron-impact dissociation of SiF4 from threshold to 300 eV are presented for formation of the neutral radicals SiF3, SiF2, SiF and Si. This measurement was accomplished with threshold-ionization mass spectrometry in a dual electron-beam device. The threshold energy for dissociation into each neutral radical was measured for the first time: 10.8 eV for SiF3, 13.9 eV for SiF2, 20.4 eV for SiF and 24.6 eV for Si. The surface loss probability of each radical and the electron-impact nitrogen dissociation were measured to calibrate the relative dissociation cross sections of SiF4. The magnitude of the cross section at its maximum is 0.68 * 10-20 m2 at 80 eV for SiF3, 0.16 * 10-20 m2 at 100 eV for SiF2, 0.019 * 10-20 m2 at 100 eV for SiF, and 0.0086 * 10-20 m2 at 120 eV for Si.