Yttrium-substituted bismuth titanate (Bi4-xYxTi3O12) thin film for use in non-volatile memories

Abstract

Fatigue-free Bi3.2Y0.8Ti3O12 (BYT) thin films were grown on Pt/TiO2/SiO2/Si substrates using direct liquid injection-metal organic chemical vapor deposition. The BYT film capacitor with top Au electrode showed higher remanent polarization (2P(r)) and lower leakage current density compared with Bi3.2La0.8Ti3O12 (BLT) film capacitors. BYT films showed strong (1 17) orientation with smaller grain size, while BLT films showed strong c-axis orientation. The 2P(r) value of the BYT capacitor was 15 muC cm(-2) and remained essentially constant up to 1 x 10(10) read/write switching cycles at a frequency of 1 MHz. The leakage current of the BYT film was 3.5 x 10(-7) A cm(-2) at an applied voltage of 2 V, which is about three orders lower than that of the BLT film. (C) 2004 Kluwer Academic Publishers.