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|Title:||Hydrogenated amorphous silicon carbide deposition using electron cyclotron resonance chemical vapor deposition under high microwave power and strong hydrogen dilution|
|Citation:||Chew, K., Rusli, Yoon, S.F., Ahn, J., Ligatchev, V., Teo, E.J., Osipowicz, T., Watt, F. (2002-09-01). Hydrogenated amorphous silicon carbide deposition using electron cyclotron resonance chemical vapor deposition under high microwave power and strong hydrogen dilution. Journal of Applied Physics 92 (5) : 2937-2941. ScholarBank@NUS Repository. https://doi.org/10.1063/1.1500418|
|Abstract:||We have investigated the growth of a-Si 1-xC x:H using the electron cyclotron resonance chemical vapor deposition (ECR-CVD) technique, under the conditions of high microwave power and strong hydrogen (H 2) dilution. The microwave power used is 900 W and a gas mixture of CH 4 and SiH 4 diluted in H 2 is varied to give carbon (C) fractions x ranging from 0 to 1. We aim to understand the effects of these deposition conditions on the characteristics of ECR-CVD grown a-Si 1-xC x:H films at different x. Their microstructure and optical properties are investigated using infrared absorption, Raman scattering, UV-visible spectrophotometry, and photothermal deflection spectroscopy. Information on the atomic fraction x is obtained with Rutherford backscattering spectrometry. The B parameter in the Tauc relation is found to decrease and the Urbach energy E u increase with x, which are indicative of a higher degree of disorder with C incorporation. At intermediate x, the presence of SiC bonds can be clearly seen from the IR absorption and Raman scattering results. The T peak around 1200 cm -1 is observed in the Raman spectra of the C-rich samples, with a redshift noted at increasing x. This suggests an increased presence of sp 3 CC bonds in these films, which is attributed to the high microwave power and strong H 2 dilution that enhance C sp 3 bonding and indirectly limit the number of C sp 2 sites. This accounts for the large E 04 gaps of more than 3.2 eV observed in such films, which are nearly saturated at large x, instead of exhibiting a maximum at an intermediate x as are commonly reported. Blue photoluminescence (PL) is observed, and the PL peak energies (E PL) are correlated to the E 04 gap. The full width at half maximum of the PL are also correlated to the Urbach energy E u. These results support that the PL broadening is attributed to the disorder broadening arising from the broad band tails. © 2002 American Institute of Physics. © 2002 American Institute of Physics.|
|Source Title:||Journal of Applied Physics|
|Appears in Collections:||Staff Publications|
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