Thermal stability of the carbon-carbon bond in Ethylene adsorbed on Si(100): An isotopic mixing study

Abstract

The dominant surface chemical process involving chemisorbed C 2H 4 on Si(100) is the desorption of the intact C 2H 4 molecule. Decomposition of C 2H 4(a) to produce SiC is a minor process on Si(100). By studying the isotopic mixing between 13C 2H 4 and 12C 2H 4 to produce 13CH 2 = 12CH 2, it has been shown that less than 1% isotopic mixing occurs in the temperature range 500– This observation excludes the recombination process 2CH 2(a) → C 2H 4(a) → C 2H 4(g) as being of importance in C 2H 4 desorpti from Si(100). In addition, the efficiency, η SiC, of SiC formation from C 2H 4 has been carefully remeasured using direct calibration of the Auger spectrometer for adsorbed carbon using C 2H 4 of known absolute coverage as a standard. We find that η Sic = 3.3 × 10 −3 SiC units per C 2H 4 collision at a Si(100) temperature of 950 K.