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(OBut)2(dmop)2] (1) and [Hf(OBut)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(OBut)4] and [Hf(OBut)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.