Abstract: A method for subjecting target substrates to a heat process under a vacuum pressure includes a transfer step, heating-up and pressure-reducing step, and heat-processing step. The transfer step is arranged to transfer into a reaction chamber a holder that supports the substrates at intervals. The heating-up and pressure-reducing step following the transfer step is arranged to heat up the reaction chamber to a process temperature, and exhaust the reaction chamber to a process pressure. During the heating-up and pressure-reducing step, the reaction chamber is set at the process pressure after being set at the process temperature, to form a state where the reaction chamber has the process temperature under a pressure higher than the process pressure. The heat-processing step following the heating-up and pressure-reducing step is arranged to subject the substrates to the heat process at the process temperature and process pressure.

Abstract: A silicon epitaxial layer is formed on the semiconductor underlayer of a target substrate (W) in the process chamber (2). This forming method includes a pressure reducing step of reducing the pressure inside the process chamber (2) accommodating the target substrate (W), a vapor phase growth step of introducing a film formation gas containing silane gas into the process chamber (2) to grow a silicon epitaxial layer on the semiconductor underlayer, and a hydrogen chloride treatment step and a hydrogen heat treatment step performed therebetween. The hydrogen chloride treatment step is arranged to introduce the first pre-treatment gas containing hydrogen chloride gas into the process chamber (2), thereby treating the atmosphere inside the process chamber (2). The hydrogen heat treatment step is arranged to introduce the second pre-treatment gas containing hydrogen gas into the process chamber (2), thereby treating the surface of the semiconductor underlayer.