Ja. Kubby et al., IMAGING DEFECT FORMATION IN THE TEMPLATE GROWTH OF NISI2 SI(111) - ANAPPLICATION OF QUANTUM-SIZE MICROSCOPY/, Physical review. B, Condensed matter, 48(7), 1993, pp. 4473-4480
The tunneling microscope is used to study the solid phase reaction of
thin nickel films on silicon substrates to form epitaxial nickel disil
icide. The initially flat Si(111)-7 X 7 substrate develops defects in
the form of surface and interface steps as the silicide reaction proce
eds, with the steps corresponding to domains of NiSi2(111) of varying
thicknesses. For low-temperature growth, the nickel disilicide terrace
s are atomically flat, whereas below the surface there is substantial
inhomogeneity. Annealing this surface to higher temperature reduces th
e subsurface inhomogeneity by diffusing residual silicon to the surfac
e to form adatom islands, trading off volume defects for surface defec
ts. We present resonant tunneling spectra for the resulting vacuum-met
al-semiconductor quantum-well structure, and discuss the conditions un
der which quantum size effects occur for carriers within the thin NiSi
2 metallic film.