HIGH-PERFORMANCE TANTALUM OXIDE CAPACITORS FABRICATED BY A NOVEL REOXIDATION SCHEME

High-performance tantalum oxide capacitors with excellent reliability have been developed by a two-step oxidation scheme. A novel anodic reoxidation process has been applied to the reactively sputter-deposited tantalum oxide films to make the densified oxide structure. The electrical and physical properties as well as the reliability of these two-step oxidized sputtered/anodized tantalum oxide films are shown to be much superior to those of conventional tantalum oxide films prepared by either anodization or sputtering alone. Capacitors made of this sputtered/anodized tantalum oxide film have greatly improved electrical properties, such as lower dissipation factors, higher breakdown fields, narrower breakdown distribution, lower leakage currents, less charge trapping, and better reliability than anodized or sputtered tantalum oxide capacitors. Tantalum oxide films prepared by the novel sputtered/anodized reoxidation process are very useful for applications to high-capacity storage capacitors in future high-density VLSI memories. © 1990 IEEE