Influence of substrate direct current bias voltage on microcrystalline silicon growth during radio-frequency magnetron sputtering

Hydrogenated microcrystalline silicon (μc-Si:H) thin films were prepared on glass, aluminum-covered glass and Si wafer substrates at various substrate bias voltages (Vsb) between –400 and +50 V, and the influence of Vsb on their structural properties was investigated. The crystallinity (crystalline volume fraction and crystallite size) of the μc-Si:H films deposited on glass remained unchanged with respect to Vsb. For μc-Si:H films deposited on aluminum within the Vsb range of –20 to +50 V, the crystallinity also remained unchanged and showed the same crystallinity as that of the films deposited on glass substrate. However, the crystallinity of the μc-Si:H films deposited on aluminum-covered substrate was reduced as Vsb decreased from –20 to –100 V, and the film at Vsb=–400 V was completely amorphous.