Effect of flux rate on AlN epilayers grown by hydride vapor phase epitaxy

Abstract

The surface morphology and crystalline quality of AlN epilayers grown by high-temperature hydride vapor phase epitaxy (HVPE) with various growth rate were investigated by AFM, XRD and cross-sectional TEM analyses. The growth rate of AlN films were controlled by regulating the flux rates of HCl and NH3 while keeping V/III ratio constant. The surface morphology of as-grown AlN films revealed that the control of the appropriate growth rate is beneficial to obtain uniform step-flow morphology. And the crystalline quality of AlN layers has been improved at an appropriate growth rate, since the growth mode of AlN under such condition is beneficial to the bending of dislocations. The dislocation bending and reduction mechanism has also been demonstrated.