作者：Byunghoon Yoon;Jennifer L. O’Patchen;Dragos Seghete;Andrew S. Cavanagh;Steven M. George;

作者单位：Department of Chemistry and Biochemistry, University of Colorado Boulder, CO 80309-0215 (USA);Department of Chemistry and Biochemistry, University of Colorado Boulder, CO 80309-0215 (USA);Department of Chemistry and Biochemistry, University of Colorado Bo

刊名：Chemical vapor deposition

ISSN：0948-1907

出版年：2009-01-05

卷：15

期：41005

起页：112

止页：121

分类号：TQ175

语种：英文

关键词：Hybrid organic-inorganic materials;Molecular layer deposition;Polymer films;Surface chemistry;

内容简介

The molecular layer deposition (MLD) of a hybrid organic-inorganic polymer based on zinc is demonstrated using sequential exposures of diethyl zinc (DEZ, Zn(CH2CH3)2) and ethylene glycol (EG, HOCH2CH2OH). This polymer is representative of a class of zinc alkoxide polymers with an approximate formula of (ZnORO)n that can be called ‘‘zincones’’. The film growth and surface chemistry during zincone MLD is studied using in-situ Fourier transform infrared (FTIR) measurements. The absorbance of the infrared features of the zincone film increase progressively versus the number of MLD cycles. The FTIR spectra after the DEZandEGexposures are consistent with the gain and loss of absorbance from CH,OH, CO, and ZnO stretching vibrations. FTIR studies also confirm the self-limiting nature of the surface reactions and monitor the temperature dependence of the film growth. Transmission electron microscope (TEM) images of ZrO2 nanoparticles show very conformal zincone films and determine that the growth rate varies from 4.0A ° per MLD cycle at 90 8C to 0.25A ° per MLD cycle at 170 8C. Quartz crystal microbalance (QCM) and X-ray reflectivity (XRR) measurements show linear zincone growth versus the number of MLD cycles. XRR studies on silicon wafers are consistent with a growth rate of 0.7A ° per MLD cycle at 130 8C. The higher growth rate on the ZrO2 nanoparticles is attributed to the lower gas conductance and possible CVD reactions in the ZrO2 nanoparticles. The reaction mechanism for zincone MLD is dependent on temperature. At higher temperatures, there is evidence for ‘‘double’’ reactions of EG because no free hydroxyl groups are observed in the FTIR spectrum after the EG exposures. The zincone film can grow in the absence of free hydroxyl groups if DEZ can diffuse into the zincone film and react during the subsequent EG exposure. The zincone films initially adsorb H2O upon exposure to air and then are very stable with time.