ATOMIC-ORDER PLANARIZATION OF ULTRATHIN SIO2 SI(001) INTERFACES/

Conventional wet cleaning and ultrahigh vacuum (UHV) heated cleaning p rior to thermal oxidation were compared with respect to their effects on extremely thin SiO2/Si(001) interface roughness. Atomically flat Si O2/Si(001) interfaces were realized by preparing the Si(001) reconstru cted surface in UHV followed by thermal oxidation. In contrast to conv entional wet cleaning, this planarization is significant in the range of oxide thickness (T-OX) < 9 nm which is an important thickness for f uture gate oxides. As for the conventional wet-cleaned surfaces, maxim um roughness of the interface was observed at T(OX)similar or equal to 4 nm which corresponds to the ''initial oxide thickness'' which appea red in the oxide growth kinetics.