Thin film transistors obtained by hot wire CVD

Hydrogenated microcrystalline silicon films obtained at low temperature (15 0-280 degrees C) by hot wire chemical vapour deposition at two different pr ocess pressures were measured by Raman spectroscopy, X-ray diffraction (XRD ) spectroscopy and photothermal deflection spectroscopy (PDS). A crystallin e fraction >90% with a subgap optical absortion 10 cm(-1) at 0.8 eV were ob tained in films deposited at growth rates >0.8 nm/s. These films were incor porated in n-channel thin film transistors and their electrical properties Tn;ere measured. The saturation mobility was 0.72 +/- 0.05 cm(2)/ V s and t he threshold voltage around 0.2 eV, The dependence of their conductance act ivation energies on gate voltages were related to the properties of the mat erial. (C) 2000 Elsevier Science B.V. All rights reserved.