Characterization of Metal-Ferroelectric-(Metal-)Insulator-Semiconductor (MF(M)IS) Structures Using (Pb, La)(Zr, Ti)O3and Y2O3Films

Metal-ferroelectric-(metal-)insulator-semiconductor (MF(M)IS) structures are fabricated and characterized using (Pb, La)(Zr0.3Ti0.7)O3(PLZT) and Y2O3films. Y2O3buffer layers are epitaxially grown on Si(111) substrates by molecular beam epitaxy and ferroelectric PLZT films are formed on (Pt/)Y2O3/Si by the sol-gel technique. It was found that the Al/Y2O3/Si MIS structure has a low leakage current of less than 10-8A/cm2. The capacitance-voltage (C-V) characteristics of the PLZT/Y2O3/Si MFIS structure exhibit a hysteresis loop due to the ferroelectricity of the PLZT film with a memory window of 1 V. On the other hand, the memory window of the Pt/PLZT/Pt/Y2O3/Si MFMIS structures is significantly improved.