Deposition of HfO2 and ZrO2 films by liquid injection MOCVD using new monomeric alkoxide precursors

Abstract

Thin films of ZrO₂ and HfO₂ have been deposited by liquid injection MOCVD using the new alkoxide precursors [Zr(OBu^t)₂(dmop)₂] (1) and [Hf(OBu^t)₂(dmop)₂] (2) [dmop = 2-(4,4-dimethyloxazolinyl)-propanolate]. The crystal structures of 1 and 2 have been determined, and they are shown to be six-coordinate monomeric complexes. They are volatile, and are significantly less reactive to air and moisture than existing Zr and Hf alkoxide precursors such as [Zr(OBu^t)₄] and [Hf(OBu^t)₄]. The ZrO₂ and HfO₂ thin films were deposited over substrate temperatures ranging from 350–550 °C. Analysis by X-ray diffraction shows that the films were deposited in the thermodynamically stable α- or monoclinic phase, and Auger electron spectroscopy shows that the ZrO₂ and HfO₂ films are non-stoichiometric and that carbon (1.9–8 at%) was present in the oxide films.