Thermal Process Effects on Grain Size and Orientation in $(Bi,La)_4Ti_3O_{12}$ Thin Film Deposited by Spin-on Method

스핀 코팅법으로 증착한 $(Bi,La)_4Ti_3O_{12}$ 박막의 후속 열공정에 따른 입자 크기 및 결정 방향성 변화

A 16Mb ITIC FeRAM device was fabricated with BLT capacitors. The average value of the switchable 2 polarization obtained m the 32k-array (unit capacitor size: 068 ${mu}m^2$) capacitors was about 16 ${\mu}C/cm^2$ at 3V and the uniformity within an 8-inch wafer was about 2.8%. But a lot of cells were failed randomly during the measuring the bit-line signal of each cell. It was revealed that the Grain size and orientation of the BLT thin film were severely non-uniform. Therefore, the uniformity of the grain size and orientation was improved by changing the process conditions of post heat treatment. The temperature of nucleation step was the very effective on varying the microstructure of the BLT thin film. The optimized temperature of the nucleation step was $560^{\circ}C$.