INHIBITION OF ATOMIC-HYDROGEN ETCHING OF SI(111) BY BORON DOPING

Subsurface boron doping reconstructs the Si(111) surface and alters the electronic character of the surface Si atoms. The interaction of atomic hydrogen with the boron-modified Si(111)-(unroofed radical 3 x unroofed radical 3)-R30-degrees surface was studied using temperature programmed desorption (TPD), high-resolution electron energy-loss spectroscopy (HREELS), and low-energy electron diffraction. In comparison to the Si(111)-(7 x 7) surface, we observe a significantly reduced hydrogen saturation coverage, measured by TPD and HREELS, and the absence of silane production. The ordered (1/3 ML) subsurface boron atoms passivate the surface Si atoms and reduce their reactivity with atomic hydrogen. This leads to a surface condition causing suppression of silicon etching by atomic hydrogen, compared to the unmodified Si(111)-(7 x 7) surface.