Adsorption and decomposition of trimethylindium on Si(110)

The adsorption and thermal decomposition of trimethylindium (TMIn) on Si(110) were studied with XPS, UPS and HREELS techniques. TMIn molecules were found to adsorb on the surface at 120 K with a partial dissociation of In-C bonds, similar to the cases of TMIn on Si(111)-7×7 and Si(100)-2×1, but to a larger extent. The cracking of the In-C bonds continued at 250 K and was completed at 550 K, as indicated by the disappearance of the In-C characteristic peaks at 61 meV in the HREELS and at 3.5 eV in the UPS spectra, as well as by the observed peak-shifting for both C(1s) and In(3d 5 2) photoelectrons in the XPS spectra. At 550 K, C-H bond breaking also occurred, indicated by the fact that the peak at 258 meV in the HREELS and the peak at 5.3 eV in the UPS spectra due to Si-H species could be observed. Above 630 K, In species started to form an island on and subsequently desorb from the surface; this was evidenced by the large peak-shifting in both In(3d 5 2) XPS and In(4d) UPS results and by the attenuation of the In(3d 5 2) XPS signal intensity, respectively. At T>950 K, the C-H bond scission and the H and In desorption were complete, with C species left on the surface forming silicon-carbide.