Static secondary ion mass spectrometry study of the decomposition of triethylgallium on GaAs (100)

The decomposition of triethylgallium (TEGa-d0) and perdeuterated triethylgallium (TEGa-d15) on Ga-rich GaAs (100) was studied using temperature programmed static secondary ion mass spectrometry (SSIMS) and temperature programmed desorption (TPD). Isothermal and temperature programmed SSIMS spectra of the TEGa-dosed surface feature three dominant hydrocarbon ions, CH3+, C2H3+, and C2H5+, whose behavior indicates the presence of two distinct ethyl ligands. The TEGa-d15 results were equivalent to the TEGa-d0 results, with the ion masses shifted by the D and H mass differences. Both CH3+ and C2H3+ SSIMS signals exhibit the same temperature dependence, staying rather constant between 140–530 K and then decreasing rapidly between 530 and 650 K. The CH3+ and C2H3+ signals disappear over the same temperature range in which C2H4 forms and desorbs from the surface in TPD; these SSIMS signals are attributed to the surface ethyl ligands that are responsible for C2H4 formation. Ethyl ligands reacting to ethylene are l...