| AVS 55th International Symposium & Exhibition | |
| Surface Science | Thursday Sessions |
| Session SS1-ThM |
| Session: | Growth and Etching on Surfaces |
| Presenter: | W.F. Van Dorp, Delft University of Technology, The Netherlands |
| Authors: | W.F. Van Dorp, Delft University of Technology, The Netherlands S. Zalkind, Rutgers, the State University of New Jersey B. Yakshinksiy, Rutgers, the State University of New Jersey T.E. Madey, Rutgers, the State University of New Jersey J.D. Wnuk, Johns Hopkins University J.M. Gorham, Johns Hopkins University H. Fairbrother, Johns Hopkins University C.W. Hagen, Delft University of Technology, The Netherlands |
| Correspondent: | Click to Email |
Electron beam-induced deposition (EBID) is a technique where adsorbed precursor molecules are dissociated by a focused beam of electrons to define metallic or semi-conducting patterns. Control over the process has developed to the extent that the amount of deposited material can be controlled (nearly) to the level of single molecules.1 However, the purity of the deposits is not yet well controlled due to lack of knowledge of the precise nature of the precursor dissociation. Therefore, we study the adsorption behaviour of (CH3)3-Pt-C5H4CH3 (a typical EBID precursor) and the dissociation cross section as a function of incident electron energy using Temperature Programmed Desorption (TPD).2,3 TPD experiments using a Au(110) sample as substrate indicate that the first monolayer in contact with the substrate has a higher desorption temperature than condensed multilayers. The adsorption energy for the monolayer in contact with the Au is estimated to be 55 kJ/mol. The desorption behaviour in the first monolayer is first order and multilayers do not form until after the first monolayer has formed; the precursor desorbs molecularly. The precursor desorbs (nearly) completely below 0 °C. To study the adsorption behaviour in a condition more typical of an EBID experiment, we deposited a several nm thick carbon/Pt containing layer on the sample. TPD measurements using this “realistic” surface show that the desorption behaviour is similar to that on clean Au(110). The peaks have their maxima in the same range of temperatures, although the peaks are wider. Using this “realistic” C/Pt surface, we studied the effect of broad beam electron irradiation on the TPD spectrum of a single monolayer of precursor. As the total electron dose increases, the area under the TPD peak for m/z = 289 decreases. Cross sections for dissociation can be calculated from the reduction in the area under the TPD peak and are about 10-16 cm2 for electron energies between 40 eV and 3 keV, comparable to those for electron induced dissociation in the gas phase.
1 W.F. van Dorp, C.W. Hagen, P.A. Crozier, P. Kruit, Nanotechnology 19 (2008) 225305.
2 N.S. Faradzhev, C.C. Perry, D.O. Kusmierek, D.H. Fairbrother, T.E. Madey, J. Chem. Phys. 121 (2004) 8547.
3 C. C. Perry, N. S. Faradzhev, D. H. Fairbrother, T. E. Madey, Int. Rev. Phys. Chem. 23 (2004) 289.