Oxidation of spatially controlled atomically flat Si 001/surface

We have demonstrated oxidation of the spatially controlled atomically flat Si 001.surface by exposing O2 gas, and investigated morphologies of the SiO2surface and the SiO2rSi 001.interface using atomic force microscopy. When the O2 pressure was low at high substrate temperatures )4008C., anisotropic surface etching occurred. Monoatomic-deep pits elongated in the direction of the dimer rows were formed on the Si 001.terraces. Thus, the O2 exposure resulted in the roughening of the atomically flat Si 001.surface. When the O2 pressure was kept high at the high substrate temperatures on the other hand, the oxidized specimens were free from the etching and had good morphologies at the SiO2 surface and the SiO2rSi 001.interface, whose root-mean-square values of roughness are small compared with a monoatomic-step-height. q1998 Elsevier Science B.V. All rights reserved