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Etching of Zirconium Oxide, Hafnium Oxide, and Hafnium Silicates in Dilute Hydrofluoric Acid Solutions

Published online by Cambridge University Press:  03 March 2011

Viral Lowalekar  and
Srini Raghavan
Viral Lowalekar
Affiliation:
Department of Materials Science and Engineering, The University of Arizona, Tucson, Arizona 85721
Srini Raghavan
Affiliation:
Department of Materials Science and Engineering, The University of Arizona, Tucson, Arizona 85721
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Abstract

Oxides and silicates of zirconium and hafnium are actively being considered and tested to replace SiO2 as the gate material. Though these materials have the high-dielectric constant (k ∼ 20–25) needed to provide a larger equivalent oxide thickness, they are very refractory and difficult to etch by wet and dry methods. In this paper, work done on wet etching of ZrO2, HfO2, and HfSixOy in dilute hydrofluoric acid (HF) solutions is presented and discussed. Experiments were done on various high-k films deposited by metalorganic chemical vapor deposition. It was found that the as-deposited high-k films can be dissolved with a good selectivity over SiO2 in dilute HF solutions, but heat-treated high-k films are difficult to etch with good selectivity over SiO2 under the same conditions.

Keywords

Chemical reactionDieletric
Type
Articles
Information
Journal of Materials Research , Volume 19 , Issue 4 , April 2004 , pp. 1149 - 1156
Copyright
Copyright © Materials Research Society 2004

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