Structure and electrical properties of AlN films prepared on PZT layers with different orientations

Abstract

c-Axis oriented AlN films were prepared on (100)-, (110)-, and (111)-oriented PZT layers by DC reactive magnetron sputtering. The evolution of c-axis preferential orientation, surface microstructure and electrical properties of the synthesized films was investigated as a function of PZT orientation. The X-ray diffraction results showed that a nearly stress free AlN film with full width at half maximum value of the rocking curve of 3.7°, can be successfully synthesized at (111)-orientated PZT layers. The change in the morphological properties with PZT orientation was investigated using the scanning electron microscopy and atomic force microscopy techniques. The morphology of the AlN films, grown on (111) PZT films, revealed good interface quality with surface roughness of 5.9nm compared to other samples. The electrical property of AlN/PZT heterostructures can be effectively improved by introducing the AlN films. Current–voltage curves of the AlN/PZT-(111) films exhibited a lowest leakage current density of approximately 10−10Acm−2 at−5V, which showed excellent insulating characteristic. It is expected that this investigation may offer some useful guidelines to the design of MFIS capacitor and other MFIS structure devices.