ATOMIC-HYDROGEN ADSORPTION ON SINTERED THIN COPPER-FILMS

Atomic hydrogen adsorption on thin copper films deposited under UHV conditions was examined by means of Thermal Desorption Mass Spectrometry (TDMS) and measurements of corresponding relative resistance changes (Delta R/R). It was found that at 78 K, within a coverage interval 0.02 < theta < 0.16, atomic hydrogen adsorption is characterized by a linear increase of Delta R/R with increasing theta. TD spectra showed a large TD peak with a temperature maximum T-m at 300 K and traces of a very small TD peak (with theta on the order of 10(-4)) at a T-m of 170 K. At theta > 0.3 a weakly bound, inferred to be an induced form of the adsorbate was seen with a T-m at 230 K. No traces of molecular hydrogen adsorption could be observed until the H-2 pressure, P, was below 0.1 Torr.