Growth and properties of YMnO3 thin films for nonvolatile memories

We have proposed ReMnO3 (Re: Rare earth elements) films for metal-ferroelectric-(insulator)semiconductor field effect transistor-(MF(I)SFET) type ferroelectric random access memories (Ferroelectric RAMs). For this kind of application, since ReMnO3 films must be fabricated on Si substrates, this paper focuses on the fabrication of YMnO3 films on Si substrates with and without buffer layers and their properties. Although only amorphous YMnO3 films are obtained without buffer layers, crystalline films are obtained using Y-Mn-O buffer layers deposited without introducing oxygen. YMnO3 films can be epitaxially grown on the top of epitaxial Y2O3 on (111)Si. For both crystalline YMnO3 films, although hysteresis behavior in D-E measurement is observed, remanent polarizations are quite small.