Comparative Surface Study on Hydrogen Terminated Si Surface Covered with Alcohols

We investigated the relative coverage of an alcohol adsorbed on a hydrogen terminated Si (H-terminated Si) surface by angle resolved X-ray photoelectron spectroscopy (ARXPS). We found that both Si2p (103.3 eV; Si-O) and O1s (532.5 eV; Si-O) spectra increased in the order of IPA < ethanol < methanol through all takeoff angles, and both spectra increased as the takeoff angle decreased in these alcohol treatments. The H-terminated Si surface was oxidized by coating these alcohols. In addition, the C1s (284.6 eV; C-H or C-C/H) spectrum slightly increased in order of IPA < ethanol < methanol through all takeoff angles, and increased as the takeoff angle decreased. The relative coverage of alcohols adsorbed on the H-terminated Si and their water contact angles are discussed in greater detail.