ADSORPTION AND REACTION OF NO ON SI(111) STUDIED BY SCANNING-TUNNELING-MICROSCOPY

By using scanning tunneling microscopy, low-energy electron diffractio n, and Auger electron spectroscopy adsorption and reaction of NO on Si (111)7x7 at 860 K and the effect of subsequent annealing to 1230 K hav e been studied. The latter results are compared with those obtained on a surface which has been heated to 1260 K during NO exposure. In both cases the previously described ''8x8'' structure has been obtained. A t 860 K etching of Si and formation of oxynitride islands are found at the same time. In scanning tunneling microscopy the 8x8 structure app ears as a rather regular array of protrusions in a mean distance of 8/ 3 a(Si). No indications of the previously proposed coincidence lattice structure [A. G. Schrott and S. C. Fain, Jr., Surf. Sci. 123, 204 (19 82)] are seen in the scanning tunneling microscopy results. (C) 1996 A merican Vacuum Society.