A study of conduction mechanisms and the frequency dependence of the junction capacitance of all-sputtered is presented. A correlation between conduction mechanisms and capacitive behaviour and the production process is established. Interface states, probably bombardment-generated, are passivated by water-related species during interface formation. This leads to a change in the conduction mechanism, from the multistep-tunneling mechanism to the tunneling/interface recombination mechanisms, and to the appearance of a relaxation in capacitance due to those interface states. These changes have repercussions on the cell photovoltaic response, increasing the efficiency from 1% to close to 4%.