MATERIALS SCIENCE AND ENGINEERING

HIGH-PERFORMANCE NANO-CAPACITORS FOR DRAM DEVICES

TiO₂ (titanium dioxide) thin-films layers have promising intrinsic properties for using them as dielectric layers in capacitor applications. Recent experimental research of G. Welsch at Case has demonstrated that TiO₂ thin-films fabricated by anodic oxidation of Ti in an aqueous electrolyte yield a better dielectric constant (ε = 60..150) and a better breakdown voltage (U_b>400 V) than TiO₂ layers made by sputter deposition.

Present research aims to explore the potential of TiO₂ layers made by anodic oxidation for industrial fabrication of nanoscopic capacitors, consisting of two Ti electrodes and a TiO₂ layer between them (Fig. 1). The goal is to fabricate a demonstrator device, to characterize (Fig. 2), rationalize, and optimize its structural and electrical properties.

Fig. 1. (a) Present technology of capacitors for DRAM devices, based on dielectric layers of perovskite ceramics. (b) Proposed technology, based on TiO₂ dielectric layers.

Fig. 2. TEM image of TiO₂ layer fabricated by anodic oxidation of Ti.