We report on the structural, optical and electrical properties of undoped microcrystalline silicon films deposited by ECR-CVD technique. In detail, films with a crystallinity fraction larger than 60%, optical absorption spectra close to those of monocrystalline silicon, deposition rate higher than 1 Angstrom /s and electron mobility of approximately 50 cm(2)/V s have been obtained at substrate temperatures ranging from 200 to 300 degreesC.