Laser-induced chemical vapor deposition of AlN films

AlN intended for metal-insulator-semiconductor applications has been prepared by laser activated chemical vapor deposition from ammonia and trimethylaluminum precursors. The films are high-density polycrystalline with 〈100〉 preferential orientation, and there is no evidence of the presence of Al2O3. A consistent band gap of 6.00±0.03 eV is obtained for film thickness in the range 0.3–1.2 μm. Conductivity is below 5×10−14 Ω−1 cm−1 at room temperature and is thermally activated with a range of excitation energies between 0.6 and 0.8 eV. The breakdown electric field is about 3×106 V/cm, while the relative permittivity varies between 7.8 and 8.2 in the frequency range 100 Hz–13 MHz.