Method for depositing microcrystalline silicon and monitor device of plasma enhanced deposition

A method for depositing a microcrystalline silicon film is disclosed, including performing an open loop and close loop plasma enhanced deposition process without and with modulating process parameters, respectively. A film is deposited by the open loop plasma enhanced deposition process till a required film crystallinity and then performing a closed loop plasma enhanced deposition process which monitors species plasma spectrum intensities SiH* and Halpha and modulates process parameters of the plasma enhanced deposition process resulting in the species concentration stabilization which controls the intensities variation of SiH* and Halpha within an allowed range of a target value for improving film depositing rate.