Investigation of the Reactions during Alkylation of Chlorine-Terminated Silicon (111) Surfaces

Absorption infrared spectroscopy (IRAS) and Rutherford backscattering (RBS) have been used to investigate the reaction of chlorine-terminated Si(111) surfaces with organometallic molecules (Grignard reagents). Although the predominant reaction leads to alkylation, with formation of covalent Si−C bonds, evidenced by a 678 cm^(-1) feature assigned to the Si−C stretch mode, solvents typically used during alkylation (tetrahydrofuran and methanol) can also react with Cl/Si(111) surfaces, either during the alkylation reaction or during the rinsing/cleaning process to form Si−OC_nH_(2n+1) as observed by the presence of a SiO−C stretch mode at 1090 cm^(-1). We also address the origin of some silicon oxidation observed after the methylation or ethylation reactions.