In order to integrate spintronic devices into well-established Si device processes, thermal stability as well as improvement of device characteristics by thermal processes is important. We investigated the influence of the post-growth annealing on a Schottky barrier metal-oxide-semiconductor field-effect-transistor (MOSFET) with epitaxial ferromagnetic MnAs/Si(0 0 1) source and drain, by evaluating the magnetic properties of MnAs and the transport characteristics of the MOSFET structure. When the post-growth annealing was performed at 500 degrees C in a N-2 atmosphere, the transport characteristics were improved preserving the ferromagnetic behavior of MnAs. As a result, the MnAs/Si(0 0 1) junction was found to have sufficiently high thermal stability for the device process up to 500 degrees C. (c) 2006 Published by Elsevier B.V.