E. Cartier, V. Narayanan, et al.
VLSI Technology 2004
High band gap, device-quality, hydrogenated amorphous silicon (a-Si) was deposited from silane at room temperature using concentric-electrode plasma-enhanced chemical vapor deposition (CE-PECVD). Increasing the flow of silane from 15 to 99 sccm resulted in a continuous increase of the optical band gap, Eopt, from 1.7 to 2.1 eV, and changed the dominant bonding configuration from Si-H to Si-H2. The total hydrogen concentration as determined from the integrated absorption of the SiHx stretching bond increased from 7% to 15%. As Eopt varied between 1.7 and 2.1 eV, the photoconductivity, σph, decreased from 10-5 to 10-7 Ω-1 cm-1 and the dark conductivity, σd, dropped from 10-10 to 10-14 Ω-1 cm-1 (σph and σd measured at room temperature after a 1 h anneal at 200°C). These results are superior to those obtained using a-SiC alloys deposited under comparable conditions (i.e., without hydrogen dilution). After annealing, three different conduction paths were identified and correlate with the silicon-hydrogen bonding configuration. The photosensitivity of high band gap a-Si films, σph/σd, follows Slobodin's rule for a-SiGe alloys. High band gap a-Si deposited by CE-PECVD has significant potential to challenge the role of a-SiC as the choice material for films with 1.7 ≲ Eopt ≲ 2.1 eV.
E. Cartier, V. Narayanan, et al.
VLSI Technology 2004
J.P. Conde, K.K. Chan, et al.
Journal of Applied Physics
M. Yang, V. Chan, et al.
VLSI Technology 2004
S. Stiffler, Carol Stanis, et al.
Journal of Applied Physics