Hydrogenated Nanocrystalline Silicon Deposited by Hot Wirechemical Vapour Deposition at High Rate

In this contribution we summarize our recent investigations on the deposition of nc-Si:H materials at a deposition rate in excess of 1.0 nm/s. Techniques to characterize the material quality include structural, optical and electrical characterization methods such as Raman spectroscopy, Fourier Transform Infrared spectroscopy, Reflection/Transmission, electronic activation energy and conductivity measurements. Sub-bandgap defects are characterized by means of Constant Photocurrent Method and Photothermal Deflection Spectroscopy. It is shown that at an adequately raised substrate temperature, nc-Si:H materials with good photoresponse can be produced at a rate beyond 1.0 nm/s. Particularly, the reverse H2 profiling technique developed earlier for low-rate nc-Si:H material deposited near the a-Si:H to nc-Si:H phase transition can also be applied to this high rate material. This warrants a homogeneous structure in the growth direction. The results of the present research can be well implemented in to an in-line deposition facility, which involves a continuously moving substrate.