Study on low-temperature growth of AlN single crystal film by ECR-PEMOCVD

The AlN film with GaN initial-layer ( GaN buffer layer and epilayer) has been grown on alpha-Al2O3 (0001) substrate by electron cyclotron resonance-plasma-enhanced metal organic chemical vapor deposition( ECR-PEMOCVD) technique at low temperatures using TMAl and high pure N-2 as Al and N sources, respectively. The effects of hydrogen plasma cleaning, nitridation and GaN inital-layer on the quality of AlN epilayer have been investigated by RHEED( reflection high-energy electron diffraction), TEM (transmission electron microscope) and XRD (x-ray diffraction). And high-quality hexagonal-phase AlN single crystal films whose cleavability is the same as the substrate have been grown at low temperatures. The full width at half maximum of XRD peaks is 12'.