Laser deposition of AlN thin films on InP and GaAs

Aluminium nitride thin films (~1000 A) were deposited by pulsed laser (ruby, 30 ns) evaporation on compound semiconductors GaAs and InP for fabrication of metal-insulator-semiconductor (MIS) diodes. The deposition was carried out with a laser energy density of 2.5 Jcm-2 at a rate of 10-11 A/pulse at ~10-6 Torr, the substrate temperature being 300 K. Low-angle X-ray diffraction showed the films to have a wurtzite structure. The resistivity of the films was 5×1012 Ω-cm with a breakdown field of 1-2×106 V-cm. The dielectric constant of the films was in the range of 7.5-7.8. A lower value of interface state density was obtained on InP (~1.8×1011 cm-2eV-1) rather than on GaAs (~8×1011 cm-2eV-1). These results are compared with earlier studies of laser-deposited BN films on InP.