Plasma enhanced chemical vapour deposition of hydrogenated amorphous silicon at atmospheric pressure

Abstract

Amorphous hydrogenated silicon films were grown using an atmospheric pressure helium and hydrogen plasma with silane added downstream of the source. A maximum deposition rate of 120 ± 12 Å min −1 was recorded at a substrate temperature of 450˚C, 6.3 Torr H 2 , 0.3 Torr SiH 4 , 778 Torr He, 32.8 W cm −3 , and an electrode-to-substrate spacing of 6.0 mm. The deposition rate increased rapidly with the silane and hydrogen partial pressures, up to 0.1 and 7.0 Torr, respectively, then remained constant thereafter. By contrast, the deposition rate decreased exponentially as the electrode-to-substrate distance was increased from 5.0 to 10.5 mm. The total hydrogen content of the films ranged from 2.5 to 8.0 ± 1.0 at%. These results together with a model of the plasma chemistry indicate that H atoms and SiH 3 radicals play an important role in the deposition process.

Atmospheric pressure plasmas: A review

“…The upper electrode is connected to the RF power supply while the lower electrode is grounded. It has been recently applied to the deposition of hydrogenated amorphous silicon [44] with silane added downstream of the hydrogen-helium plasma. The device is shown in Fig.…”

Experimental study of fractal clusters formation from nanoparticles synthesized by atmospheric pressure plasma-enhanced chemical vapor deposition

“…has been considered to be one of the most promising plasma-assisted technologies for plasma chemical synthesis (Alexandrov 2005;Barankin 2006;Chen 2007;McIlroy 2003;Moravej 2004;Zhu 1990). This type of plasma technology is characterized by approximately three times higher partial pressures of precursors in comparison to low-pressure processes and because of this reason, it is expected to provide sufficiently higher rate of chemical reaction.…”

Conformal coating of amorphous silicon and germanium by high pressure chemical vapor deposition for photovoltaic fabrics

“…a-Si:H is one of the most technologically important and cost-effective semiconductors and is deposited by CVD on large area planar substrates for applications such as thin film transistors, backplane displays, and solar cells. 11 Passivation of silicon dangling bonds by hydrogen is essential for acceptable electrical and optical properties for a-Si:H. To overcome the kinetic barrier in the pyrolysis reaction of a-Si:H, maintain a desirable reaction rate at low enough temperatures (i.e., below 500 • C 12 ) and thus allow for sufficient incorporation of hydrogen; athermal processes such as plasma-enhanced CVD (PECVD), 13 hot wire CVD, 14 and photosensitized CVD 15 are used to activate the decomposition of the silane precursor molecules. However, these techniques usually require large, complex, and expensive equipment.…”