Formation of Y2O3 interface layer in a YMnO3/Si ferroelectric gate structure

During the crystallization of amorphous YMnO3 thin film on Si (100) at 870 degreesC in a dry O-2 ambient, a nanoprecipitate layer was found between the YMnO3 and the Si substrate. Lattice image processing as well as high-resolution transmission electron microscopy showed that the nanoprecipitate layer was a cubic Y2O3 phase. Also, it showed that a native oxide was consumed by the reaction with the Y atoms. This [111] Y2O3 layer exhibited a local epitaxial relationship to the c-axis oriented (0001) YMnO3. The formation of Y2O3 phase and the consumption of native oxide at the YMnO3/Si interface are due to the Y atom which is better than Mn in its ability to oxidize during heat treatment in O-2 ambient. (C) 2000 American Institute of Physics. [S0003-6951(00)04550-2].