Title: Hydrogen and hydrogen sulfide thermal effusion from a-Si,S:H alloy

Authors: Safwan R. Arekat

Addresses: Department of Physics, University of Bahrain, P.O. Box 32038, Sakhir, Kingdom of Bahrain

Abstract: Thermal gas effusion measurements were carried out in an ultrahigh vacuum system equipped with a quadrupole mass analyser. The hydrogen and hydrogen sulphide thermal effusion rates from amorphous hydrogenated silicon-sulphur films grown by a CVD glow discharge technique were measured. The hydrogen effusion rates show up to three peaks at different temperatures, the low-T peak corresponds to H₂ escape from void structures, the mid-T peak originates from polysilane-like structures, whereas the high-T peak results from breaking bulk Si-H bonds. For low sulphur content films, a sharp effusion peak of H₂S is observed at around 840°C, which is indicative of the onset of crystallisation of the material. This peak broadens and shifts to low temperatures at higher sulphur concentrations. A kinetic model is employed to estimate the activation energies and bond strengths from the thermal gas effusion data.

Keywords: hydrogenated amorphous silicon; amorphous silicon-sulphur alloys; hydrogen effusion; desorption kinetics; chemical vapour deposition; CVD; thermal gas effusion; crystallisation; kinetic modelling; activation energy; bond strength; semiconductor industry; optoelectronics.

DOI: 10.1504/IJNP.2010.037137

International Journal of Nanoparticles, 2010 Vol.3 No.4, pp.333 - 340

Received: 15 Mar 2010
Accepted: 25 Mar 2010
Published online: 26 Nov 2010 *

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