Atomic structure of random and c-axis oriented YMnO3 thin films deposited on Si and Y2O3/Si substrates

We have studied the atomic structure of YMnO3 deposited on Si and Y2O3 with high-resolution transmission electron microscopy and fast Fourier transforms-filtered lattice image analysis during furnace and rapid thermal annealing (RTA) processes. For the YMnO3/Si, it is found that the YMnO3 layer is c-axis oriented with an amorphous bottom region after furnace annealing at 850 degreesC for 1 h. In contrast, after RTA at 850 degreesC for 3 min the bottom region forms YMnO3 polycrystalline layer with the {(1) over bar2 (1) over bar2} plane parallel to the surface. When an Y2O3 layer is interposed between YMnO3 and Si, a c-axis oriented YMnO3 layer grows on a [111]-oriented Y2O3 layer. Memory window and leakage current density of the c-axis YMnO3/[111] Y2O3 bilayers are strongly improved due to an aligned [0001] unipolar axis. (C) 2003 American Institute of Physics.