Crystal and Electrical Characterizations of Epitaxial CeXZr1-XO2 Buffer Layer for the Metal/Ferroelectric/Insulator/Semiconductor Field Effect Transistor

Abstract

We evaluated the crystallinities of CeX Zr1-X O2 (X=0.10–0.20) thin films used as intermediate layer for metal/ferroelectric/insulator/semiconductor field effect transistors (MFIS-FETs), using reflection high-energy electron diffraction (RHEED), X-ray diffraction (XRD) and X-ray pole figure measurement. The crystal alignments of CeX Zr1-X O2 films on Si(100) were CeX Zr1-X O2[100]//Si[100] or CeX Zr1-X O2[100]//Si[001], in the plane. The breakdown field of CeX Zr1-X O2 was about 3 MV/cm (at I=1 nA/cm2). From C-V measurements, it was found that the electrical properties of the intermediate layers of the MFIS-FETs were good. Oriented perovskite PbTiO3 films were deposited on CeX Zr1-X O2/Si(100) substrates by digital chemical vapor deposition (CVD). These PbTiO3 films included many PbTiO3 grains aligned with the [100] or [001] axis parallel to the [101] axis of the CeX Zr1-X O2 crystals at the plane in the PbTiO3/CeX Zr1-X O2 interface. From C-V measurements of an Al/PbTiO3/CeX Zr1-X O2/Si(100) sample, we obtained a threshold hysteresis (memory window) of about 1.4 V.