Thermal and electron-driven chemistry of CCl4 on clean and hydrogen precovered Si(100)

Abstract

The thermal and electron activated properties of CCl4 on Si(100), with and without adsorbed hydrogen, have been investigated in the temperature range 100–1100 K using temperature programmed desorption (TPD), electron stimulated desorption, and x-ray photoelectron spectroscopy. Dosed at 100 K but not exposed to electrons, molecular CCl4 desorbs from both surfaces between 120 and 170 K with coverage-dependent monolayer and multilayer peaks. An etching product, SiCl2 desorbs from Si(100), but not H–Si(100). Electron irradiation of CCl4 on both surfaces at 100 K drives reactions with ejection and retention of products. Compared to thermal activation, SiCl2 TPD is enhanced on Si(100), while on H–Si(100), the SiCl2 TPD channel opens and HCl peaks appear at 610 and 820 K in TPD. Ejection of neutral CClx (x⩽4) and Cl is observed on both Si(100) and H–Si(100), and the CCl+ ion signal decays with a cross section of (1.3±0.1)×10−16 on Si(100) and (2.8±0.5)×10−17 cm2 on H–Si(100). On both surfaces, the electron activated cross section describing the decay of the CCl4 TPD peak area is 9×10−17 cm2. C2Clx (x=2, 4, and 6) appear in post-irradiation TPD.

Room-Temperature Chemisorption and Thermal Evolution of 1,1-Dichloroethylene and Monochloroethylene on Si(111)7×7: Formation of Vinylidene and Vinylene Adspecies

“…The nearly identical profile shapes of these higher-temperature features of masses 98 and 63 (with an intensity ratio of 1.8 for mass 63 to mass 98) for iso- DCE also indicate that they originate from the same desorption product. Because SiCl 2 + (mass 98) and SiCl + (mass 63) are found to be in comparable amounts from electron impact studies of gaseous SiCl 2 , , the parent desorption species is likely SiCl 2 . In our TDS experiments for iso- DCE and MCE, we have also monitored but found no mass 133, corresponding to SiCl 3 + of the heavier etching product SiCl 4 , confirming SiCl 2 as the main etching product.…”

Room-temperature chemisorption and thermal evolution of perchloroethylene and trichloroethylene on Si(111)7×7: Formation of chlorinated vinylene and vinylidene and acetylide adspecies, and thermal etching reactions

“…The nearly identical profiles with similar desorption maxima for the mass 98 and mass 63 TDS features (with an intensity ratio of 1:1.8) also indicate that they originate from the same desorption product. Because SiCl þ 2 and SiCl + are found to be in comparable amounts from electron impact studies of gaseous SiCl 2 [34,35], the parent desorption species is likely SiCl 2 . Furthermore, we have also monitored mass 133, corresponding to SiCl þ 3 of the heavier etching product SiCl 4 , but found no desorption feature, confirming SiCl 2 as the main etching product.…”

Decomposition of Carbon Tetrachloride on Gold Surfaces

“…They show an important yield at around 160 K related to the desorption of different species. The desorption temperature of CCl 4 depends on the nature of the surface and film thickness, e.g., 142 K on H-Si(100) 40 or 165 K (three-layer-thick film) on Ru. 32 The detected species in Figure 1 are attributed to the cracking of CCl 4 in the mass spectrometer.…”