Evidence for enhanced desorption of hydrogen atoms from a Si(1 0 0) surface induced by slow highly-charged ions

We report evidence for an enhanced desorption of hydrogen atoms from a Si(1 0 0) surface bombarded by 30 keV Xeq+ (q = 6–22) ions. The measured desorption yield amounts to 0.76 and 2.2 hydrogen atoms per incident Xe10+ and Xe18+ ion, respectively. For understanding the behaviour of hydrogen desorption from Si, another experiment was carried out to see the hydrogen signals as a function of time for about 140 min after deliberately introducing hydrogen into the target chamber and then shut off the valve. The results are discussed in the light of potential sputtering which essentially dominates for ions at higher charge states and the interpretation is supported by theoretical estimates.