Potential Step Coverage for Supercritical Fluid Deposition of TiO2 by Numerical Simulation and Microcavity Analysis

The potential step coverage for supercritical fluid deposition of TiO2 (TiO2–SCFD) was evaluated using numerical simulation based on kinetic parameters. A required parameter, the ratio of the surface reaction rate constant to the diffusivity, ksD, was retrieved experimentally. The simulations revealed that a step coverage of 0.97 was possible on deep trenches (6.75-μm depth, 125-nm width) without compromising the growth rate. Conformal deposition by TiO2−SCFD is possible on narrow trenches having the same aspect ratio. The simulations were validated experimentally. Our methodology for evaluating the potential step coverage is also equally applicable to SCFD of other metal oxides. © 2013 The Electrochemical Society. [DOI: 10.1149/2.009309ssl] All rights reserved. Manuscript submitted May 3, 2013; revised manuscript received June 26, 2013. Published July 9, 2013. Supercritical fluid deposition (SCFD) is a promising technol-ogy that enables conformal deposition on high-aspect-ratio features at low temperature.1,2 In SCFD, metal-organic precursors and oxi-dants/reductants that are dissolved in supercritical CO2 (scCO2) react on the surface of a heated substrate and deposit. A lower process tem-perature compared with conventional dry processes such as chemical vapor deposition (CVD) is possible because of the solvent effect o