Characterization of thin polycrystalline silicon films deposited on glass by CVD

BENVENUTO, A. G.; BUITRAGO, R. H.; BHADURI, A.; LONGEAUD, C.; SCHMIDT, J. A.

SEMICONDUCTOR SCIENCE AND TECHNOLOGY

IOP PUBLISHING LTD

Lugar: Londres; Año: 2012 vol. 27 p. 1250131 - 1250135

0268-1242

We deposited polycrystalline silicon (poly-Si) thin films on commercial float glass by chemical vapour deposition from trichlorosilane at temperatures between 735 and 870 ºC. The structural properties of the films were evaluated by means of scanning electron microscopy, x-ray diffraction, atomic force microscopy, reflectance in the ultraviolet region and Raman spectroscopy. The electrical characterization involved measurements of dark conductivity and photoconductivity as a function of temperature, Hall effect, ambipolar diffusion length from the steady-state photocarrier grating technique and density of defects by means of modulated photoconductivity. By using boron tribromide as a doping agent, degrees of doping ranging from intrinsic to clearly p-doped were obtained. The process, the reactants and the substrate used are of low cost, and proved to be adequate for direct poly-Si deposition, giving films of good structural and electrical properties.