Role of hydrogen bonding environment in a-Si:H films for c-Si surface passivation
- 30 June 2008
- journal article
- Published by American Vacuum Society in Journal of Vacuum Science & Technology A
- Vol. 26 (4), 683-687
- https://doi.org/10.1116/1.2897929
Abstract
The search for an ideal surface passivation layer of crystalline silicon (c-Si) to be employed in a silicon heterojunction photovoltaic device has garnered much attention. The leading candidate is a few nanometers of intrinsic amorphous silicon ((i)a-Si:H) film. Reported dependencies of film surface passivation quality on substrate preparation, orientation, and deposition temperature have been extended in this work to include H2 to SiH4 dilution ratio and postdeposition annealing. Simple avoidance of the deposition regimes that lead to epitaxial growth of Si on the c-Si substrate produces decent lifetimes on the order of 500μs. Subsequent low temperature annealings cause an important restructuring of Si–H bonding at the a-Si:H∕c-Si interface increasing the amount of monohydride at the c-Si surface. This restructuring would reduce the c-Si surface defect density and cause an improvement of surface passivation as confirmed by effective lifetime measurements. Final effective carrier lifetimes up to 2550μs are achieved postannealing. Initial results indicate the improvement depends on surplus SiH2 from the interface region.Keywords
This publication has 22 references indexed in Scilit:
- Abruptness of a-Si:H∕c-Si interface revealed by carrier lifetime measurementsApplied Physics Letters, 2007
- Impact of epitaxial growth at the heterointerface of a-Si:H∕c-Si solar cellsApplied Physics Letters, 2007
- High-rate plasma-deposited SiO2 films for surface passivation of crystalline siliconJournal of Vacuum Science & Technology A, 2006
- Effect of emitter deposition temperature on surface passivation in hot-wire chemical vapor deposited silicon heterojunction solar cellsThin Solid Films, 2005
- Influence of stoichiometry of direct plasma-enhanced chemical vapor deposited SiNx films and silicon substrate surface roughness on surface passivationJournal of Applied Physics, 2005
- Generalized analysis of quasi-steady-state and transient decay open circuit voltage measurementsJournal of Applied Physics, 2002
- Surface passivation of p-type crystalline Si by plasma enhanced chemical vapor deposited amorphous SiCx:H filmsApplied Physics Letters, 2001
- Surface passivation of silicon solar cells using plasma-enhanced chemical-vapour-deposited SiN films and thin thermal SiO2/plasma SiN stacksSemiconductor Science and Technology, 2001
- Carrier recombination at silicon–silicon nitride interfaces fabricated by plasma-enhanced chemical vapor depositionJournal of Applied Physics, 1999
- Plasma-enhanced chemical-vapor-deposited oxide for low surface recombination velocity and high effective lifetime in siliconJournal of Applied Physics, 1993