M. Iwami et al., Studies of 4H-SiC(0001)Si(root 3 x root 3) and (0001)C(3 x 3) surfaces andtheir metallization process by Ni using STM, AES and LEED, SURF REV L, 7(5-6), 2000, pp. 679-682
Several methods have been tried to prepare clean surfaces of 4H-SiC(0001)Si
and C, whose surface atomic, or electronic, structures have been studied b
y LEED (low energy electron diffraction) STM (scanning tunneling microscopy
) and AES (Auger electron spectroscopy). Some sequential chemical treatment
s, for example, agitation in an organic solvent and dipping in HF solution,
followed by the heating of a SiC wafer in UHV (ultrahigh vacuum, below 10(
-7) Pa) at 950 degreesC, gave either a root3 x root3 or 3 x 3 superstructur
e, observed by LEED (low energy electron diffraction), for the SiC(0001) Si
or C surface, respectively. An elongated NH4F treatment followed by a heat
treatment in UHV at similar to 950 degreesC gave a rather flat region to b
e investigated by STM, where a root3 x root3 superstructure for the SiC(000
1) Si surface has been observed. In the case of metal (Ni) atom deposition
on SiC(0001) Si(root3 x root3) and (0001)C(3 x 3) surfaces, AES and LEED an
alysis have clarified that deposited metal atoms form islands up to similar
to 5 Angstrom. However, Ni atoms dispersed uniformly at the very beginning
of the deposition, which means that the Ni overlayer piles up in layer fol
lowed by island growth mode.