AVS 45th International Symposium
    Electronic Materials and Processing Division Thursday Sessions
       Session EM+PS-ThM

Paper EM+PS-ThM1
Growth and Characterization of Ba@sub 0.6@Sr@sub 0.4@TiO@sub 3@ Thin Films on Si with Pt Electrodes

Thursday, November 5, 1998, 8:20 am, Room 314/315

Session: Processing of High K Dielectrics for DRAMs
Presenter: L. Kinder, Los Alamos National Laboratory
Authors: L. Kinder, Los Alamos National Laboratory
I.L. Grigorov, Los Alamos National Laboratory
C. Kwon, Los Alamos National Laboratory
Q.X. Jia, Los Alamos National Laboratory
L. Luo, Applied Materials, Inc.
J. Zhao, Applied Materials, Inc.
Correspondent: Click to Email
The application of high dielectric constant materials like barium strontium titanate in dynamic random access memories requires the integration of these materials into the existing Si technology. In this study, pulsed laser deposition was used to grow Ba@sub 0.6@Sr@sub 0.4@TiO@sub 3@ (BST) thin films on Si with Pt electrodes. Through scanning electron microscopy, x-ray diffraction, and electrical characterization, the Pt/BST/Pt capacitor processing on Si has been optimized. BST films on Pt sputtered at high power tends to show high leakage current. However, high leakage current is prevented if the Pt is sputtered at low powers. Low power deposition leads to not only smooth Pt film but also less hillocks. The smoother Pt electrodes allow the BST to grow with greater crystallinity. 150 nm BST on Pt shows a dielectric constant over 400 and dielectric loss of 0.01 at 10 kHz. The quality of the dielectric can be further improved by first depositing a thin seed layer of BST at lower temperatures. We have successfully used 20 nm BST deposited by metal-organic chemical vapor deposition as a seed layer to improve the over all device performance. The influence of interface and of initial nucleation of BST films on the structural and dielectric properties of the thin film capacitors will be also discussed.