Photoconductive a-Si: H with dominant monohydride bonding prepared by DC-Magnetron sputtering

A description is given of a dc-magnetron sputtering apparatus used for deposition of hydrogenated amorphous silicon (a-Si:H) by reactive sputtering in an argon/hydrogen discharge. The physical properties of the deposited a-Si:H films are determined by measuring the photo and dark conductivity, the Tauc gap, the IR absorption and by ESR and RBS measurements. The influence of the main deposition parameters (hydrogen partial pressure, dc-power) on the film properties is discussed. The films reveal a minimal value of dark conductivity of σD = 10−11 (Ωcm)−1 and a four decade higher photoconductivity even for samples prepared at growth rates of 7 μm/h. In all films the hydrogen is predominantly bound in monohydride complexes (SiH).