Showing papers by "Joydeep Dutta published in 1992"
TL;DR: In this paper, the dependence of intrinsic stress in hydrogenated amorphous silicon on excitation frequency in a plasma-enhanced chemical vapor deposition process was investigated, and it was shown that intrinsic stress is positively associated with excitation frequencies.
Abstract: Dependence of intrinsic stress in hydrogenated amorphous silicon on excitation frequency in a plasma-enhanced chemical vapor deposition process
51 citations
TL;DR: In this paper, the use of plasma excitation frequencies f in the VHF band (30-300 MHz), and particularly of f=70 MHz, for the high-rate deposition of amorphous hydrogenated silicon (a-Si:H) is described.
Abstract: The use of plasma excitation frequencies f in the VHF band (30-300 MHz), and particularly of f=70 MHz, for the high-rate deposition of amorphous hydrogenated silicon (a-Si:H) is described. Deposition rates, using monosilane (SiH4) as source gas, are thereby increased roughly five fold to over 10 A/s as compared with the conventional case of RF plasma enhanced chemical vapour deposition with f=13.56 MHz. This may possibly be attributed to an enhancement in the high-energy tail of the electron energy distribution function (EEDF) of the plasma. Thereby, no noticeable deterioration in film properties is found. Characteristics of VHF-deposited a-Si:H films are extensively reported, including properties like microstructure, hydrogen effusion behaviour and its low internal mechanical stress. High quality hydrogenated microcrystalline silicon (μc-Si:H) can be deposited at low substrate temperature and low plasma power densities thanks to VHF glow discharge. This can be linked to a reduction in sheath potential and to the energy of the ions arriving at the growing surface. Thereafter, use of VHF plasma in applications such as 100 μm thick a-Si:H layer for particle detectors and powder-free deposition of solar cells with efficiencies over 8% are reported.
45 citations
TL;DR: In this article, a surface profiler was used to measure the stress and thickness of the films and the surface roughness of the film was evaluated by the UV-light reflectance loss.
Abstract: Films were prepared under argon and xenon dilution with silane concentrations ranging from 3 to 100% using the very high frequency glow discharge (VHF-GD) technique. The H-content and the microstructure were determined by IR-spectroscopy. A surface profiler was used to measure the stress and thickness of the films. The surface roughness of the films was evaluated by the UV-light reflectance loss. The samples were further characterized by dark- and photoconductivity, by CPM and by PDS, both in annealed and light-soaked state. Down to silane concentrations of about 10–20% film properties change only little; however, for both dilution series the microstructure parameter shows a minimum and the internal stress a maximum near 20% silane concentration. At still higher rare gas dilution the film properties change drastically. Surprisingly the photoconductivity remains almost constant for all gas dilutions. It is shown how these changes in the film properties are linked with the light induced degradation.
9 citations
TL;DR: The role played by the xenon ions in the growth of the materials prepared from xenon-diluted silane source gas has been considered in this article, where it is demonstrated that the xenons are responsible for the growth the materials showing stable photoconductivity behavior under light illumination.
Abstract: The contribution of ion bombardment to the growth of hydrogenated amorphous silicon prepared by plasma-enhanced chemical vapour deposition from silane and xenon-diluted silane source gases was studied by applying an external d.c. voltage to the substrate electrode. The role played by the xenon ions in the growth of the materials prepared from xenon-diluted silane source gas has been considered. It is demonstrated that the xenon ions are responsible for the growth of the materials showing stable photoconductivity behaviour under light illumination.
2 citations