Detrimental effects of atomic hydrogen on the formation of Schottky barriers in p-type Ge

Abstract

In this study on p-type Ge, hydrogen is found to be mobile at room temperature and always negatively charged. Ge samples of different acceptor dopings were treated in a dc-hydrogen plasma at temperatures between 70 °C and 250 °C or were etched in different wet chemical solutions. Schottky contact formation was hindered by the hydrogen contamination of the samples. Stable Schottky contacts on p-type Ge doped with Ga, B or Al can be fabricated by annealing the samples at about 300 °C prior to the metal evaporation. The previously reported Fermi-level pinning seems to have no influence on the formation of Schottky contacts on p-type Ge.