Preparation and characterization of CrO2 films by Low Pressure Chemical Vapor Deposition from CrO3

• Published in: Thin solid films 2013-07, Vol.539, p.1-11
• Main Authors: Aguilera, C., González, J.C., Borrás, A., Margineda, D., González, J.M., González-Elipe, A.R., Espinós, J.P.
• Format: Article
• Language: English
• Subjects: Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Chromium dioxide; Chromium trioxide; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Epitaxy; Exact sciences and technology; Ferromagnetism; Low Pressure Chemical Vapor Deposition; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Physics; Raman; Structure and morphology; thickness; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology; X-ray diffraction
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2013.04.118

Highly oriented CrO2 thin films have been heteroepitaxially grown on TiO2 rutile (110), (100) and (001) single crystalline substrates, by Low Pressure Chemical Vapor Deposition from CrO3 as precursor and flowing oxygen as carrier gas, under a pressure of 67Pa. The experimental conditions were fine tuned by depositing on polycrystalline Ti foils, to improve the purity of the films and the deposition rate. A maximum deposition rate of 175nmh−1 was obtained. The composition and texture of films, up to 2μm thick, have been determined by X-ray diffraction (XRD) and Micro Raman, while their microstructure has been examined by Scanning Electron Microcopy and Atomic Force Microscopy, and their magnetic behavior has been tested by superconducting quantum interference device magnetometry. These techniques reveal that the phase purity, texture, microstructure and thickness of these films are dependent on the crystalline face of the rutile substrate and the deposition temperature. Thus, microscopy techniques, XRD and Raman spectroscopy confirm that highly textured CrO2 films were always obtained on the three rutile substrate faces when deposition temperature ranges between 616K and 636K. But these techniques also show that CrO2 films are unpurified with inclusions or patches of Cr2O3, for the most of the substrates and especially at high deposition temperatures. Magnetic measurements conclusively demonstrate that pure CrO2 films are only obtained when TiO2 (110) is used as a substrate. •CrO2 films were grown by Low Pressure Chemical Vapor Deposition by using CrO3.•CrO2 films were grown at pressures as low as 67Pa.•Pure and highly textured CrO2 films were obtained on TiO2 (110) rutile substrates.•Minor amounts of Cr2O3 were found on TiO2 (100) and (001) rutile substrates.