Substrate Dependent Texture and Heteroepitaxy for Group IIIA Nitride Films by the X-Ray Precession Method

ABSTRACTThe X-ray precession method has been utilized to study texture and heteroepitaxy for thin films of the Group IIIA nitrides deposited on a variety of amorphous and single-crystal substrates. Films of InN were synthesized by reactive rfmagnetron sputtering [employing an elemental target and N2 as the sputtering gas], while the GaN films were deposited by metalorganic chemical vapor deposition [utilizing (CH 3 ) 3Ga and NH3 as sources]. The quality of (00.1) textured films of InN on fused quartz and slightly off-axis (111) Si are taken as initial examples of the versatility of the X-ray precession method. The powder rings evolving from a lack of azimuthal coherence for InN films grown on quartz are contrasted with the scattering from weakly correlated (pseudo heteroepitaxial) domains for films grown on (111) Si. These latter scattering features are then compared with those from the true heteroepitaxial deposition of InN onto the (111) face of cubic ZrO2. And, finally, the scattering from the heteroepitaxial growth of InN and GaN on the (00.1) face of sapphire and some initial studies on the effect of nucleation layers on twinning in the GaN films are presented.