Microcrystalline silicon (μc-Si:H) of truly intrinsic character can be deposited by plasma-enhanced chemical vapor deposition (PECVD) when dichlorosilane (SiH2Cl2) is added. A dark conductivity of 1.6×10-8 S/cm and an activation energy of 0.62 eV are obtained. No special gas purification or microdoping is required. SiH2Cl2 in small amounts has the additional effect of enhancing the crystallinity and reducing the oxygen incorporation by over a factor of 2. Sub-band-gap absorption spectroscopy indicates a low defect density. © 1998 American Institute of Physics.