ATOMIC-SCALE PLANARIZATION OF SIO2/SI(001) INTERFACES

Atomically flat silicon-oxide interfaces were obtained after preparing the Si(001)-2 X 1 reconstructed surface in ultrahigh vacuum (UHV) followed by native oxide growth and then conventional thermal oxidation. When the surface is prepared with conventional wet cleaning prior to oxidation, the flat interfaces initially tend to become rough and then smoother with increasing oxide thickness. In comparison with the conventional interfaces, UHV surface planarization is significant up to oxide thicknesses of about 8 nm. This thickness range will be extremely important for future ultralarge-scale integrated circuits (ULSIs).