Growth of AlN by pulsed and conventional MOVPE

Aluminium nitride was grown on c-plane sapphire by metal organic vapor phase epitaxy (MOVPE) at temperatures of 1070 °C by a pulsed growth method and in continuous growth mode at temperatures up to 1270 °C. For both methods the V/III ratio was varied and different approaches for the growth start were investigated. The crystal quality was mainly characterized by scanning electron microscopy and high resolution X-ray diffraction which showed unusual line shape for certain samples. Both growth methods enabled the growth of more than 1μm thick, atomically flat, Al-polar layers with edge type dislocation densities in the order of 3×1010cm−2 for pulsed samples and 5×109cm−2 for conventionally grown samples.