C–V characteristics of Pt/PbZr0.53Ti0.47O3/LaAlO3/Si and Pt/PbZr0.53Ti0.47O3/La0.85Sr0.15CoO3/LaAlO3/Si structures for ferroelectric gate FET memory

Abstract Pt/PbZr 0.53 Ti 0.47 O 3 (PZT)/LaAlO 3 (LAO)/Si and Pt/PbZr 0.53 Ti 0.47 O 3 /La 0.85 Sr 0.15 CoO 3 (LSCO)/LaAlO 3 /Si structures for ferroelectric field effect memory applications were fabricated on n-type Si substrate by pulsed laser deposition (PLD). The Auger electron spectrometry (AES) analysis shows that a LaAlO 3 buffer layer can effectively prevent Si and Ti, Pb interdiffusion between PZT and Si substrate. For both of the structure, the current density–voltage measurement shows a typical leakage current density of about 10 −7  A/cm 2 at 8 V applied voltage. Furthermore, it has been demonstrated that the PbZr 0.53 Ti 0.47 O 3 /LaAlO 3 /Si structures and Pt/PbZr 0.53 Ti 0.47 O 3 /La 0.85 Sr 0.15 CoO 3 /LaAlO 3 /Si structures exhibit ferroelectric switching properties, showing a memory window as large as 2 and 2.9 V, respectively, under a ramp rate of 200 mV/s from −6 to +6 V driving voltage at 1 MHz. It is believed that the La 0.85 Sr 0.15 CoO 3 buffer layer deposited on LaAlO 3 layer can improve the crystalline properties of PZT films, and then result in lager polarization of PZT and lager memory windows for Pt/PbZr 0.53 Ti 0.47 O 3 /La 0.85 Sr 0.15 CoO 3 /LaAlO 3 /Si structures.