In situ Si flux cleaning technique for producing atomically flat Si(100) surfaces at low temperature

We have developed a method for removing oxides and producing atomically flat Si(100) surfaces with single atomic height steps using a Si flux cleaning technique. By introducing a Si flux in the range 1.0-1.5 Angstrom/s at the onset of an SiO2 thermal desorption step as low as 780 degrees C, scanning tunneling microscopy (STM) and atomic force microscopy images reveal smooth surfaces with atomically flat terraces with an rms roughness of 0.5 Angstrom and single step heights of 1.4 Angstrom. STM reveals that A- and B-type steps are present across the entire area of the scanned surface. Desorption of the surface oxide layer with Si fluxes below this range results in rougher surfaces with pits similar to 50 Angstrom deep and 1000 Angstrom across. For Si fluxes above this range, no pits are seen but atomic steps are not visible on the surface. (C) 1997 American Institute of Physics.