The effect of tin on the thermal chemistry of CH 3 on Si/Cu(100) was investigated using temperature programmed desorption (TPD), X-ray photoelectron spectroscopy (XPS), ion scattering spectroscopy (ISS), low energy electron diffraction (LEED), Auger electron spectroscopy (AES), and high-resolution helium atom scattering (HAS). The Si/Cu(100) substrate was prepared by exposure to silane at 420 K. The TPD results showed that (CH 3) 3SiH was the dominant product desorbing from Si/Cu(100) after exposure to CH 3 radical, and that its desorption was sensitive to the concentration of Si in the outermost surface. For the silane-saturated surface, Si sat/Cu(100), (CH 3) 3SiH desorbed near 500 K, while for subsaturated surfaces, Si unsat/Cu(100), (CH 3) 3SiH desorbed at both 270 and 500 K. The addition of Sn to the Si sat/Cu(100) surface, prior to CH 3 exposure, led to a shift in the (CH 3) 3SiH desorption feature to higher temperatures. Tin addition to Si unsat/Cu(100) surface changed the product distribution. Specifically, with Sn coadsorption levels in excess of 0.7 ML, the dominant product is the fully methylated species, (CH 3) 4Si, at 430 K.
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films
- Materials Chemistry