Temperature suppression of STM-induced desorption of hydrogen on Si(100) surfaces

The temperature dependence of hydrogen (H) desorption from Si(100) H-terminated surfaces by a scanning tunneling microscope (STM) is reported for negative sample bias. It is found that the STM induced H desorption rate (R) decreases several orders of magnitude when the substrate temperature is increased from 300 to 610 K.

This is most noticeable at a bias voltage of -7 V where R decreases by a factor of 200 for a temperature change of 80 K, whilst it only decreases by a factor of 3 of at -5 V upon the same temperature chan ge. The experimental data can be explained by desorption due to vibrational heating by inelastic scattering via a hole resonance.

This theory predicts a weak suppression of desorption with increasing temperature due to a decreasing vibrational lifetime, and a strong bias dependent suppression due to a temperature dependent lifetime of the hole resonance. (C) 1999 Elsevier Science B.V. All rights reserved.