Microcrystalline silicon (mu c-Si:H) films were deposited at 250 degrees C from the reaction of SiH4 with H-2-He gas excited in an inductively couple remote plasma. The deposition rate; microstructure, and material properties of mu c-Si:H depended on the composition of hydrogen and helium in the plasma. Si films deposited on a hydrogen plasma showed columnar and microcrystalline structure with a grain size of about 200 Angstrom or less, and had an optical bandgap of about 2.05 to 2.1 eV. The microstructure parameter (SiH2/[SiH + SiH2] in the film) and Urbach tail slope decreased with increasing H-2 fraction in the plasma gas. On the other hand, amorphous (a-Si:H) film was deposited with higher deposition rate when pure He was used as plasma gas and the optical bandgap of this film was 2.18 eV. The surface of a-Si:H film was smoother than that of mu c-Si:Pi.