In this work is presented the study of microcrystalline silicon PECVD process through highly diluted silane in hydrogen discharges. The investigation is performed by applying different non - intrusive plasma diagnostics (electrical, optical, mass spectrometric and laser interferometric measurements). These plasma diagnostics are applied for prospecting the optimal experimental conditions from the μc-Si:H deposition rate point of view. Namely, the main characteristics of the effect of frequency, discharge geometry, power consumption and total gas pressure on the deposition process are presented successively. The proper combination of experimental conditions that result from the optimal choice of each of the above - mentioned discharge parameters and lead to high microcrystalline silicon deposition rates (7,5 Å/sec) is presented. The prerequisites for the achievement of high deposition rates are also discussed.