Growth and properties of silicon films on aluminum-nitride films on sapphire

Epitaxial layers of silicon have been grown on aluminum-nitride films on sapphire by vapor-phase deposition using pyrolysis of silane. The structure of the silicon films is examined by the reflection electron diffraction technique and shown to be a single crystal of orientation (100)Si∥ (112̄0)AlN∥ (011̄2)Al₂O₃. Lattice matching between Si and AlN along orthogonal axes of [100] Si are 0.78 and 9.0%, respectively. The growth and electrical properties of silicon films are described in some detail. Resistivity and mobility of p-type and n-type silicon films have been measured as functions of temperature. The maximum mobility of 150 cm²/V sec has been obtained for film thickness between 1 and 4 μm. The aluminum autodoping effect upon these films is found to be higher than that of silicon films on sapphire used as control samples.