Low-temperature gas-source molecular beam epitaxy using hydride sources for the fabrication of Si thin layers was investigated. In the case of a Si2H6 source, the temperature dependence of the growth rate is relatively small in the desorption- and/or decomposition-dominated region at temperatures of 300-500 degrees C, which is useful for atomic- and molecular-level controlled growth. Simultaneous and alternate supply of oxygen prevented the deposition of SiO2 and resulted in the deposition of Si. Supplying oxygen brought about a decrease of the deposition rate of Si.