The microstructural study of wide-band gap semiconductor AlN thin films grown on (0001) and (101̄2) sapphire and (111), (100) Si was carried out using plan-view and cross-sectional high-resolution electron microscopy and x-ray diffraction. The films were grown by MOCVD from TMAl + NH3 + N2 gas mixture. Epitaxial relationship for AlN grown on (0001) α-Al2O3 was determined to be the following: (0001)AlN ∥ (0001)sap with the 300 in-plane rotation - [011̄0]AlN ∥ [1̄21̄0]sap. We report also TEM observation of the following epitaxial relationship of the AlN/(101̄2)α-Al2O3 heterostructure: (112̄0)AlN ∥ (101̄2)sap; AlN ∥ [1̄011]sap and [11̄00]AlN ∥ [12̄10]sap. These epitaxial relationships were determined to be controlled by the bonding of Al and O ions at the interface. The study of interfaces and the defects present in the film was also carried out. Main type of defects were established to be inverted domain boundaries, misfit and threading dislocations - in the films on (0001) sapphire, and stacking faults of high density in the films on (101̄2) sapphire. The epitaxial AlN films on (0001) sapphire contained dislocation density about 1010 cm-2 and exhibited device quality electrical characteristics. The films on both orientations of Si were found to be highly 〈0001〉 textured polycrystalline.
|Original language||English (US)|
|Number of pages||6|
|Journal||Materials Research Society Symposium - Proceedings|
|State||Published - Jan 1 1996|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials