Silicon surface passivation by atomic layer deposited Al{sub 2}O{sub 3}
- Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands)
- Institut fuer Solarenergieforschung Hameln/Emmerthal (ISFH), Am Ohrberg 1, D-31860 Emmerthal (Germany)
Thin Al{sub 2}O{sub 3} films with a thickness of 7-30 nm synthesized by plasma-assisted atomic layer deposition (ALD) were used for surface passivation of crystalline silicon (c-Si) of different doping concentrations. The level of surface passivation in this study was determined by techniques based on photoconductance, photoluminescence, and infrared emission. Effective surface recombination velocities of 2 and 6 cm/s were obtained on 1.9 {omega} cm n-type and 2.0 {omega} cm p-type c-Si, respectively. An effective surface recombination velocity below 1 cm/s was unambiguously obtained for nearly intrinsic c-Si passivated by Al{sub 2}O{sub 3}. A high density of negative fixed charges was detected in the Al{sub 2}O{sub 3} films and its impact on the level of surface passivation was demonstrated experimentally. The negative fixed charge density results in a flat injection level dependence of the effective lifetime on p-type c-Si and explains the excellent passivation of highly B-doped c-Si by Al{sub 2}O{sub 3}. Furthermore, a brief comparison is presented between the surface passivations achieved for thermal and plasma-assisted ALD Al{sub 2}O{sub 3} films prepared in the same ALD reactor.
- OSTI ID:
- 21137460
- Journal Information:
- Journal of Applied Physics, Vol. 104, Issue 4; Other Information: DOI: 10.1063/1.2963707; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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