Tetrazinc oxo hexakis(diethylcarbamate) Zn4O(O2CNEt2)6 is volatile (sublimes at 170°C/ 0.1Torr). It decomposes at 400°C by the following reaction: Zn4O(O2CN(CH2CH3)2)6 → 4ZnO+6C2H5NCO+6C2 H4 +3H2O
Zn4O(O2CNEt2)6 has been applied as single source precursor for the CVD growth of ZnO films on Si (100) substrates; the precursor was vaporized at 190-195°C, growth pressure was <0.1Torr, deposition temperatures 300-600°C. 600nm films were grown at growth rate ~200nm/h. The deposited films were polycrystalline having dense columnar structure and preferred c-axis orientation. Films morphology was similar to that of RF sputtered films, but not exhibiting the strain and stress usually inherent in as-deposited RF sputtered films, what presents an advantage of growing ZnO by MOCVD using Zn4O(CO2NEt2)6, which is a simple one-step process producing high-quality films with a lower growth temperature. The grown ZnO layers were characterized by XPS, XRD and electron microscopy. Piezoelectric measurements indicated piezoelectric responses close to that of single-crystalline ZnO (piezoelectric coefficient d33 ~12 pm/V). [[i],[ii]]
It was found by SEM that the columnar structure of grown ZnO films depended on the incident angle between substrates and vapor sources; however, according to XRD, the [0 0 2] crystallographic orientation of ZnO thin films was perpendicular to the substrate plane, irrespective of the incident angle, and was not aligned with the columnar growth orientations as may be expected; the easily alignment of c-axis orientation of SS CVD ZnO thin films is easily aligned with the (0 0 2) plane surface of the substrate due to its surface anisotropy and the optimal growth on the face with highest density and lowest surface-free energy.XPS measurements revealed absence of decomposed precursor residues in the bulk of ZnO films and the films are stoichiometric with O/Zn atomic ratio very close to ZnO single crystal..[[iii],[iiii]]
[i] A. J. Petrella, H. Deng, N. K. Roberts, R. N. Lamb, Chem. Mater., 2002, 14 (10), pp 4339–4342, DOI: 10.1021/cm0204324 « Single-Source Chemical Vapor Deposition Growth of ZnO Thin Films Using Zn4O(CO2NEt2)6 »
[ii] A.J. Petrella, R.N. Lamb, N.K. Roberts, US 6808743 B2, Growth of ZnO film using single source CVD , http://www.google.com/patents/US6808743
[iii] H. Deng, J.J. Russell, R.N. Lamb, B. Jiang, Y. Li, X.Y. Zhou, Thin Solid Films, Vol. 458, Iss. 1–2, 30 June 2004, Pages 43-46, https://doi.org/10.1016/j.tsf.2003.11.288 , “Microstructure control of ZnO thin films prepared by single source chemical vapor deposition”, http://www.sciencedirect.com/science/article/pii/S0040609003018789
[iiii] Deng Hong, B. Gong, A. J. Petrella, J. J. Russell, R. N. Lamb, Science in China Series E: Technological Sciences, 2003, Vol.46, Iss.4, pp 355–360
Characterization of the ZnO thin film prepared by single source chemical vapor deposition under low vacuum condition