Metal Oxide Thin Films Deposited from Metal Organic Precursors in Supercritical CO₂ Solutions


This work demonstrates a novel method for deposition of metal oxide thin films, including Al₂O₃, ZrO₂, MnOₓ, and RuOₓ where the metal-organic precursors and oxidizing agents are delivered in liquid and supercritical CO₂. A cyclic deposition process is presented where reactants are introduced sequentially to control surface adsorption and byproduct removal steps. Reactions are studied in a hot wall reactor at pressures ranging from 1600 to 3600 psi at 80-200°C, and X-ray photoelectron spectroscopy and infrared transmission confirmed metal oxide formation. We show that hydrogen peroxide is a viable O source for oxide deposition, whereas tert-butyl peracetate, which is a good electron acceptor, is less suited for oxygen donation. Capacitance versus voltage analysis of resulting Al₂O₃ films show good dielectric properties after post-deposition anneal. We believe that the good solvation properties of supercritical CO₂ can aid in the delivery of precursors and in the removal of byproducts for advanced low-temperature processing of oxides and other materials of interest in electronic applications.


Chemical and Biochemical Engineering

Keywords and Phrases

Cyclic Deposition; Metal Organic Percursors; Metal Oxide Thin Films; Surface Adsorption, Carbon Dioxide; Deposition; MOS Devices; Organic Compounds; Supercritical Fluids; X Ray Photoelectron Spectroscopy, Thin Films

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Article - Journal

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© 2005 American Chemical Society (ACS), All rights reserved.

Publication Date

01 Oct 2005