Optoelectronic properties, structure and composition of a-SiC:H films grown in undiluted and H{sub 2} diluted silane-methane plasma
- Dipartimento di Chimica Applicata e Scienza dei Materiali, Facolta di Ingegneria, Universita di Bologna, v.le Risorgimento 2, I-40136 Bologna (Italy)
- Dipartimento di Fisica ed Unita INFM del Politecnico di Torino, C.so Duca degli Abruzzi 24, I-10129 Torino (Italy)
- Elettrorava S.p.A., Via Don Sapino 176, I-10040 Savonera, Torino (Italy)
- CNR-Istituto LAMEL, Via Gobetti 101, I-40129 Bologna, Italy I-40129 Torino (Italy)
a-SiC:H films with energy gap in the range 2.00{endash}2.65 eV have been grown by plasma enhanced chemical vapor deposition in undiluted and H{sub 2} diluted SiH{sub 4}+CH{sub 4} gas mixtures, by making use of optimized deposition conditions. A complete picture of structural, compositional, optoelectronic, and defective properties for high quality films has been drawn for the first time. We show that the addition of H{sub 2} to the gas mixture leads to a different chemical composition of the deposited films; in particular, carbon incorporation is enhanced and a carbon fraction in the solid matrix up to C/(C+Si){approx}0.45 can be obtained. These films have a higher mass density, a reduced microvoid and carbon cluster concentration, a better structural connectivity, and improved optoelectronic properties. For samples with optical gap below 2.4 eV, the reduced defect concentration of H{sub 2} diluted films results in an increase of the photoconductivity gain and the steady-state ({eta}{mu}{tau}){sub ss} values up to two orders of magnitude. {copyright} {ital 1997 American Institute of Physics.}
- OSTI ID:
- 530020
- Journal Information:
- Journal of Applied Physics, Vol. 81, Issue 12; Other Information: PBD: Jun 1997
- Country of Publication:
- United States
- Language:
- English
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