Low-temperature preparation of SrBi 2 Ta 2 O 9 ferroelectric thin film by pulsed laser deposition and its application to metal-ferroelectric-insulator-semiconductor structure with nitride buffer layers

Abstract

SrBi2Ta2O9 (SBT) ferroelectric thin films have been deposited at temperatures as low as 500 degree(s)C by Pulsed Laser Deposition method on silicon nitride (SiNx) and silicon oxynitride (SiON), being insulating barrier against inter-diffusion. Metal-Ferroelectric-Insulator-Semiconductor (MFIS) structures has been fabricated using SiNx/SiO2/Si and SiON/Si and shows good C-V hystereses. It is confirmed by RBS analysis and C-V characteristics that the SiNx layer shows good barrier effect compared with SiO2 layer. It is also clarified from the direction and voltage-scanning speed of in the C-V curve that their MFIS structures show hysteresis induced by ferroelectric polarization. An Al/SBT/SiO2/Si structure shows a large memory window in C-V curve and a smaller shift than those in the Al/SBT/SiO2/Si structure. An Al/SBT/SiON/Si structure also shows good C-V characteristics whose gradient corresponding to the SiO2/Si interface trap is very small. Moreover, retention characteristics of the memorized states of the capacitance have been measured and analyzed, taking into account leakage current through ferroelectric and insulator films.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.