Study of fluorine (XeF2) adsorption and of oxygen/fluorine coadsorption on silicon using infrared reflection absorption spectroscopy

摘要: Infrared reflection absorption spectroscopy has been used to study the chemisorption of fluorine (by exposure XeF2) on polycrystalline Si surfaces in ultrahigh vacuum and under low‐pressure steady‐state conditions. Adsorption at 300 K leads sequential formation mono‐, di‐, trifluoride SiFx groups. Annealing successively higher temperature forms more ≡SiF by decomposition =SiF2 –SiF3. After a 770 anneal, only 890 cm−1 band remains is removed F desorption ∼820 K. Similar results are obtained continuous XeF2 flux with, addition, appearance near weak feature possibly due adsorbed SiF4. Based part these results, an estimate can be made rate‐limiting step reaction. In high‐temperature limit (T≥650 K) it appears conversion =SiF2; whereas, K, SiF4 from The effects fluorination pre‐ postexposure O2 have also observed. Preadsorbed O stabilize...