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 5x10-6 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, whiich was formed with a reacton probability of --5x10-2 at room temperature. In the presence of the ion beam three products, SiF4, SiF2 and F2 (or F), were detected with formation probabilities of --1x10-1, 6x10-2 and 7x10-2 respectively. Increasing surface temperature reduced the ion-enhanced reactivity