Please use this identifier to cite or link to this item: http://hdl.handle.net/2445/32233
Title: In situ spectroellipsometric study of the nucleation and growth of amorphous silicon
Author: Canillas i Biosca, Adolf
Bertran Serra, Enric
Andújar Bella, José Luis
Drevillon, B.
Keywords: Silici
Semiconductors amorfs
El·lipsometria
Silicon
Amorphous semiconductors
Ellipsometry
Issue Date: 1990
Publisher: American Institute of Physics
Abstract: A detailed in situ spectroellipsometric analysis of the nucleation and growth of hydrogenated amorphous silicon (a:Si:H) is presented. Photoelectronic quality a‐Si:H films are deposited by plasma‐enhanced chemical vapor deposition on smooth metal (NiCr alloy) and crystalline silicon (c‐Si) substrates. The deposition of a‐Si:H is analyzed from the first monolayer up to a final thickness of 1.2 μm. In order to perform an improved analysis, real time ellipsometric trajectories are recorded, using fixed preparation conditions, at various photon energies ranging from 2.2 to 3.6 eV. The advantage of using such a spectroscopic experimental procedure is underlined. New insights into the nucleation and growth mechanisms of a‐Si:H are obtained. The nucleation mechanism on metal and c‐Si substrates is very accurately described assuming a columnar microstructural development during the early stage of the growth. Then, as a consequence of the incomplete coalescence of the initial nuclei, a surface roughness at the 10-15 Å scale is identified during the further growth of a‐Si:H on both substrates. The bulk a‐Si:H grows homogeneously beneath the surface roughness. Finally, an increase of the surface roughness is evidenced during the long term growth of a‐Si:H. However, the nature of the substrate influenced the film growth. In particular, the film thickness involved in the nucleation‐coalescence phase is found lower in the case of c‐Si (67±8 Å) as compared to NiCr (118±22 Å). Likewise films deposited on c‐Si present a smaller surface roughness even if thick samples are considered (>1 μm). More generally, the present study illustrates the capability of in situ spectroellipsometry to precisely analyze fundamental processes in thin‐film growth, but also to monitor the preparation of complex structures on a few monolayers scale.
Note: Reproducció del document publicat a: http://dx.doi.org/10.1063/1.346452
It is part of: Journal of Applied Physics, 1990, vol. 68, num. 6, p. 2752-2759
Related resource: http://dx.doi.org/10.1063/1.346452
URI: http://hdl.handle.net/2445/32233
ISSN: 0021-8979
Appears in Collections:Articles publicats en revistes (Física Aplicada)

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