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 Å/s at the onset of an ${\mathrm{SiO}}_{\mathrm{2}}$ thermal desorption step as low as 780 °C, scanning tunneling microscopy (STM) and atomic force microscopy images reveal smooth surfaces with atomically flat terraces with an rms roughness of 0.5 Å and single-step heights of 1.4 Å. 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 ∼50 Å deep and 1000 Å across. For Si fluxes above this range, no pits are seen but atomic steps are not visible on the surface.