Surface characterization of quinhydrone-methanol and iodine-methanol passivated silicon substrates using X-ray photoelectron spectroscopy

Hydrogen-terminated silicon substrates were passivated with quinhydrone-methanol (QHY/ME) and iodine-methanol (I ₂/ME), and the chemical changes occurring at the surface were investigated using X-ray photoelectron spectroscopy (XPS). The XPS surface studies demonstrate that QHY/ME passivation provides reduced oxidation, less carbon contamination, and a chemically inert surface. Electrical characterization also demonstrates higher minority carrier lifetimes of QHY/ME passivated substrates as compared to I ₂/ME passivated substrates. The quality of surface treatment was also characterized using the contact angle measurement, which confirms the presence of a hydrophobic organic layer on the surface after QHY/ME passivation. Si 2p XPS spectra of the QHY/ME, I ₂/ME samples, and H-terminated silicon. With a peak at 102.9 eV for I ₂/ME, it is evident that it provides poor surface passivation than QHY/ME where no surface oxidation is observed.