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High deposition rate nanocrystalline silicon with enhanced homogeneity
Author(s) -
Verkerk Arjan,
Rath Jatindra K.,
Schropp Ruud
Publication year - 2010
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.200982883
Subject(s) - silane , materials science , silicon , nanocrystalline material , homogeneity (statistics) , diffusion , plasma , deposition (geology) , analytical chemistry (journal) , growth rate , chemical engineering , nanotechnology , chemistry , composite material , metallurgy , chromatography , thermodynamics , paleontology , statistics , physics , mathematics , geometry , quantum mechanics , sediment , biology , engineering
Abstract High rate growth of hydrogenated nanocrystalline silicon (nc‐Si:H) brings additional challenges for the homogeneity in the growth direction, since the start‐up effects affect a larger portion of the film, and the very high degree of depletion increases the influence of back diffusion from the inactive region into the plasma zone. It was calculated that back diffusion plays a role in the regime for high deposition rate (4.5 nm/s) via the residence time for particles in the plasma and the corresponding diffusion length for silane from outside the plasma. The stabilization time for back diffusion was derived and found to be on the order of tens of seconds. Experiment showed that the incubation layer for nc‐Si:H is very thick in films deposited at a high rate compared to films deposited in a regime of lower deposition rate. The use of a hydrogen plasma start greatly reduced this incubation layer. Further control of the crystalline fraction could be achieved via slight reduction of the degree of depletion via the silane flow.