Ion-Enhanced Chemical Reaction of XeF2 with Silicon by Modulated Molecular Beam Mass Spectrometry

The reaction of XeF2 with the Si(100) surface was studied by modulated (10–1000 Hz) molecular beam-mass spectrometry in the temperature range 300–1300K and equivalent XeF2 pressure of 5×10−6 to 10−4 Torr. Simultaneous bombardment of the reacting surface by Ar+ was used to determine the extent of ion-enhancement of the reaction.In the absence of the ion beam, the main reaction product was SiF4, which was formed with a reaction probability of ˜5×10−2 at room temperature. In the presence of the ion beam three products, SiF4, SiF2 and F2 (or F), were detected with formation probabilities of ˜1×10−1, 6×10−2 and 7×10−2 respectively. Increasing surface temperature reduced the ion-enhanced reactivity.