Electrical and chemical characterization of chemically passivated silicon surfaces

The surface composition of chemically passivated silicon substrates is investigated using XPS and FTIR techniques. The samples are passivated with methanol, quinhydrone-methanol and iodine-methanol solution after HF treatment. The minority carrier lifetimes of these chemically passivated silicon substrates are also measured. Quinhydrone-methanol solution provides a chemically inert surface and a considerably longer minority carrier lifetime. © 2008 IEEE

Band-bending at buried SiO2/Si interface as probed by XPS

X-ray photoelectron spectroscopy is used to probe the photoinduced shifts in the binding energies of Si2p, O1s, and C1s of the SiO2/Si interfaces of a number of samples having oxide and/or thin organic layers on top of p- and n-Si wafers. Whereas the photoinduced shifts, in each and every peak related, vary from 0.2 to 0.5 eV for the p-type samples, the corresponding shifts are substantially smaller (<0.1 eV) for the n-type, regardless of (i) oxidation route (thermal or anodic), (ii) thickness of oxide layer, (iii) nature of organic layer, or (iv) color of three illuminating sources we have used. This leads us to conclude that these particular photoshifts reflect the charge state of the SiO2/Si interface, even in the case of a 20 nm thick oxide, where the interface is buried and cannot be probed directly by XPS. © 2013 American Chemical Society