INTERACTION OF VINYLTRIMETHYLSILANE WITH THE SI(111)-(7X7) SURFACE

Vinyltrimethylsilane (vtms) serves as a ligand in the precursor molecu le Cu-(I)(vtms)(hfac) used in copper chemical vapor deposition. Invest igations of the interaction of vtms with the Si(111)-(7x7) surface uti lizing scanning tunneling microscopy, Auger electron spectroscopy, and thermal desorption spectroscopy (TDS) are reported. The adsorption is found to be highly site sensitive with an initial sticking coefficien t most probably in excess of 0.03. With the exception of hydrogen, TDS spectra do not display vtms or any other desorbing species. Heating o f the vtms covered surface to approximate to 530 degrees C leads to th e formation of three-dimensional clusters which remain stable in shape and size up to temperatures as high as 1100 degrees C. We believe the observed clusters consist of carbon and/or SiC. In addition. the obse rvation of (5x5) reconstructed areas between the clusters suggests the deposition of silicon during the annealing process. This indicates th at vtms undergoes thermal decomposition on a silicon surface. This is in significant contrast to the observed behavior on metal and insulati ng surfaces. Consequently we cannot expect contaminant-free interfaces between the Si(111) substrate and copper films grown from the Cu-(I)( vtms)(hfac) precursor. (C) 1996 American Vacuum Society.