The structural and electrical properties have been investigated of antimony doped polycrystalline silicon films obtained by molecular beam deposition on oxidized silicon substrates. We show that low-resistivity films with smooth morphology are obtained by solid phase crystallization of antimony doped amorphous silicon layers deposited at 250 °C. A resistivity of 4.3 mΩ cm is obtained by crystallizing the films at temperatures as low as 650 °C for 15 min. In situ crystallization of the amorphous silicon is absolutely necessary to achieve low resistivities. We also show that direct deposition above 650 °C gives rise to polycrystalline silicon with much higher resistivities.