A Significant Improvement in Memory Retention of Metal-Ferroelectric-Insulator-Semiconductor Structure for One Transistor-Type Ferroelectric Memory by Rapid Thermal Annealing

概要

論文の詳細を見る
A rapid thermal annealing (RTA) process has improved the crystallinity of the ferroelectric SrBi2Ta2O9 (SBT) thin film in metal-ferroelectric-insulator-semiconductor (MFIS) structures. The RTA temperature and time were in the ranges from 600 to 1000°C and 30 s to 1 min, respectively. X-ray diffraction (XRD) patterns showed clear preferential perovskite SBT(115) peaks in the temperature range. The RTA increases grain size to approximately 180 nm but markedly decreases surface roughness to approximately 5 nm due to having a shorter annealing time than the furnace annealing. Leakage current density through the MFIS is below $5\times 10^{-8}$ A/cm2, and is fairly reduced especially at the low electric field region as a result of the shorter RTA time. Finally, a very long retention time of $6\times 10^{5}$ s (i.e., one week) was obtained by the RTA at 1000°C for 30 s. The extrapolated retention time from the data was about $3\times 10^{7}$ s (i.e., one year).
2003-04-15