Effects of annealing temperatures on the electrical properties of pulsed laser deposited Bi3.25La0.75Ti3O12 thin films for field effect transistor-type memory device

Electrical characterizations of a metal-ferroelectric-insulator-semiconductor field effect transistor (MFISFET) using Au/Bi3.25La0.75Ti3O12/Si3N4/Si(1 1 1) were investigated by studying the effects of the annealing conditions. Ferroelectric Bi3.25La0.75Ti3O12 (BLT) was prepared on 15 nm Si3N4 coated p-type Si(1 1 1) substrates by the pulsed laser deposition method at a deposition temperature of 400 °C and an oxygen pressure of 200 m Torr. The crystalline structures showed polycrystalline films with preferable c-axis orientations at higher annealing temperatures. The capacitance–voltage (C–V) measurements for the as-deposited films, 600 and 700 °C annealed films showed a decreasing memory window value of 1.31, 0.78, and 0.36 V, respectively. The generation of low coercive values for higher annealed films is known to be the main cause for such results.