Hydrogen-induced crystallization of amorphous silicon thin films. I. Simulation and analysis of film postgrowth treatment with H{sub 2} plasmas
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106-5080 (United States)
We present a detailed atomic-scale analysis of the postdeposition treatment of hydrogenated amorphous silicon (a-Si:H) thin films with H{sub 2} plasmas. The exposure of a-Si:H films to H atoms from a H{sub 2} plasma was studied through molecular-dynamics (MD) simulations of repeated impingement of H atoms with incident energies ranging from 0.04 to 5.0 eV. Structural and chemical characterizations of the H-exposed a-Si:H films was carried out through a detailed analysis of the evolution of the films' Si-Si pair correlation function, Si-Si-Si-Si dihedral angle distribution, structural order parameter, Si-H bond length distributions, as well as film surface composition. The structural evolution of the a-Si:H films upon exposure to H atoms showed that the films crystallize to form nanocrystalline silicon at temperatures over the range of 500-773 K, i.e., much lower than those required for crystallization due to thermal annealing. The MD simulations revealed that during H exposure of a-Si:H the reactions that occur include surface H adsorption, surface H abstraction, etching of surface silicon hydrides, dangling-bond-mediated dissociation of surface hydrides, surface H sputtering/desorption, diffusion of H into the a-Si:H film, and insertion of H into strained Si-Si bonds.
- OSTI ID:
- 20884692
- Journal Information:
- Journal of Applied Physics, Vol. 100, Issue 5; Other Information: DOI: 10.1063/1.2229426; (c) 2006 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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Related Subjects
ADSORPTION
ANNEALING
BOND LENGTHS
CORRELATION FUNCTIONS
CRYSTALLIZATION
DESORPTION
ETCHING
HYDROGEN
MOLECULAR DYNAMICS METHOD
NANOSTRUCTURES
ORDER PARAMETERS
PLASMA
SEMICONDUCTOR MATERIALS
SILANES
SILICON
SIMULATION
SPUTTERING
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0400-1000 K
THIN FILMS