Title :
Preparation and characterization of (Bi,La)Ti3O12 thin films for nonvolatile memory
Author :
Hwang, Sun Hwan ; Rho, Jun Seo ; Chang, Young Chul ; Chang, Ho Jung
Author_Institution :
Dept. of Electron. Eng., Dankook Univ., Chungnam, South Korea
Abstract :
Bi3.7La0.75Ti3O12 (BLT) ferroelectric thin films were prepared on Pt/Ti/SiO2/Si substrates by the sol-gel method. The as-coated films were crystallized by post-annealing at temperatures between 650°C and 750°C for 30 min. The BLT thin films exhibited typical bismuth-layered perovskite structures and the crystalline quality was improved by the post-annealing in air ambient. The AES depth profiles indicated that there were no remarkable interfacial reaction layers between BLT film and lower electrode. The dielectric constant and the dissipation factor of BLT films post-annealed at 750°C were about 402 and 0.04 at 5 kHz, respectively. The leakage current density of the BLT films annealed at 650°C was found to be 5×10-7 A/cm2 at 3 V. The BLT film annealed at 650°C exhibited ferroelectric properties with a remanent polarization 2Pr (Pr+-Pr- ) of 32.5 μ C/cm2 and showed no degradation after 10 10 polarization switching cycles under ±5 V bipolar pulse, indicating good fatigue properties
Keywords :
Auger electron spectra; annealing; bismuth compounds; dielectric polarisation; ferroelectric storage; ferroelectric thin films; integrated memory circuits; lanthanum compounds; permittivity; sol-gel processing; (Bi,La)Ti3O12 ferroelectric thin films; 3 V; 30 min; 5 V; 5 kHz; 650 to 750 C; AES depth profiles; Auger electron spectra; BLT thin films; Bi3.7La0.75Ti3O12 -Pt-Ti-SiO2-Si; Bi3.7La0.75Ti3O12 ferroelectric thin films; NVFeRAM; Pt-Ti-SiO2-Si; Pt/Ti/SiO2/Si substrates; ambient air post-annealing; as-coated film crystallization; bipolar pulses; bismuth-layered perovskite structures; crystalline quality; dielectric constant; dissipation factor; fatigue properties; ferroelectric properties; film characterization; film preparation; interfacial reaction layers; leakage current density; lower electrode; nonvolatile ferroelectric random access memories; nonvolatile memory; polarization switching cycles; post-annealing temperature; remanent polarization; sol-gel method; Annealing; Bismuth; Crystallization; Dielectric thin films; Ferroelectric films; Ferroelectric materials; Polarization; Semiconductor thin films; Substrates; Temperature;
Conference_Titel :
Electronic Materials and Packaging, 2001. EMAP 2001. Advances in
Conference_Location :
Jeju Island
Print_ISBN :
0-7803-7157-7
DOI :
10.1109/EMAP.2001.983982
