ULSI DRAM 의 capacitor 절연막용 BST 박막의 제작과 특성에 관한 연구

초록

We have studied the preparation and the properties of Ba1-xSrxTiO3 (BST) thin films by using the sol-gel method. Through the comparison of the effects of various solvents and additives in making slutions, we estalish the production method of the stable solution which generates the high quality of BST film. We also set up the heat-treatment condition for depositing the BST thin film through the TGA and XRD analyses. Through the comparison of the surface conditions of BST films deposited on Pt/Ta/SiO2/Si and Pt/Ti/SiO2/Si substrates, we find that Ta is more efficient diffusion barrier of Si than Ti so that Ta layer prevents the formation of hillocks. We fabricate the planar type capacitor and measure the dielectric properties of the BST thin film deposited on the Pt/Ta/SiO2/Si substrate. Dielectric constant and dielectric loss tangent at 1V, 10kHz, and leakage current density at 3V of our BST thin film are 339, 0.052 and 13.3μA/cm2, respectively.