P. Brogueira et al., LOW FILAMENT TEMPERATURE DEPOSITION OF A-SI-H BY HOT-WIRE CHEMICAL-VAPOR-DEPOSITION, Journal of applied physics, 78(6), 1995, pp. 3776-3783
Hydrogenated amorphous silicon, alpha-Si:H, is deposited from silane a
nd hydrogen by hot-wire chemical vapor deposition using a tungsten wir
e filament at a temperature T-fil = 1200 degrees C. Film properties de
pend on whether the films were deposited using filaments with an accum
ulated deposition time lower than 90 min (''new'' filaments) or longer
than 90 min (''old'' filaments), The deposition rate for films deposi
ted with ''new'' filaments is 4 times higher than that for aged filame
nts. For ''new'' filaments, a monotonic increase of the growth rate, r
(d), with the pressure is observed, as well as a maximum of r(d) for F
-H2/F-SiH4 close to unity. The optoelectronic properties are controlle
d by the substrate temperature T-sub, and show different dependences f
or ''new'' and ''old'' filaments, The Urbach band tail energy, E(u), i
s lower for films deposited with ''new'' filaments. A kinetic growth m
odel for hot-wire chemical vapor deposition in the T-fil similar to 12
00 degrees C regime is proposed. (C) 1995 American Institute of Physic
s.