Growth of Amorphous Silicon Germanium (a-SiGe:H) Alloys Thin Film by PECVD

Mursal Mursal (Department of Physics, Syiah Kuala University, Banda Aceh)
A. Supu (Department of Physics, Nusa Cendana University, Kupang)
I. Usman (Department of Physics, Haluoleo University, Kendari)
T. Winata (Laboratory For Materials Electronic Physics, Department of Physics, ITB)
Sukirno Sukirno (Laboratory For Materials Electronic Physics, Department of Physics, ITB)
M. Barmawi (Laboratory For Materials Electronic Physics, Department of Physics, ITB)

Indonesian Journal of Physics (IJP)
Vol 15 No 2 (2004): Vol. 15 No.2, April 2004

Hydrogenated amorphous silicon-germanium (a-SiGe:H) alloys thin films had been grown by Plasma Enhanced Chemical Vapor Deposition (PECVD) method. The films were grown on corning glass # 7059 from a gas mixture of silane (SiH4) and germane (GeH4) 10% diluted in hydrogen (H2). UV-VIS-NIR spectra analysis of a-SiGe:H alloys thin films showed that the sub-bandgap absorption α(hν) spectra of a-SiGe:H alloys shift to lower photon energy with increasing in GeH4 flow rate. The optical bandgap of a-SiGe:H alloy decreased non linearly from 0.94 eV – 0.75 eV with increasing in GeH4 flow rate from 2.5 sccm – 25 sccm. The photo-sensitivity (σph/σd) of a-SiGe:H thin films were improved as the optical bandgap (Eopt) increased.