We report a detailed study of chromium solubility and secondary phase formation in MOCVD grown (Cr, Zn)O-based films on silicon (100). Simultaneous deposition of 0.15M Cr(TMHD) and 0.025M Zn(TMHD) based precursors in an oxidizing environment with a flow ratio of 1:10 resulted in secondary phase formation rather than uniform Cr doping. Based on several surface and micro-structural techniques, we have identified nano-crystalline ZnCr2O4 and disordered Cr2O3 as the secondary Cr-containing phases that nucleate. Analysis suggests that ZnCr2O4 crystallites are dispersed throughout the film and that disordered Cr2O3 layer may form at the interface. These results reveal a strong tendency for Cr to exist in octahedral, rather than tetrahedral coordination.
Revised: March 30, 2007 |
Published: January 17, 2007
Citation
Saraf L.V., M.H. Engelhard, P. Nachimuthu, V. Shutthanandan, C.M. Wang, S.M. Heald, and D.E. McCready, et al. 2007.Nucleation and Growth of MOCVD Grown (Cr, Zn)O Films – Uniform Doping vs. Secondary Phase Formation.Journal of the Electrochemical Society 154, no. 3:D134-D138.PNNL-SA-51245.doi:10.1149/1.2424422