Atomic Scale Morphology of Hydrogen-Terminated Si(100) Surfaces Studied by Fourier-Transform Infrared Attenuated Total Reflection Spectroscopy and Scanning Probe Microscopies

Abstract

Using Fourier-transform infrared attenuated total reflection (FT-IR-ATR) spectroscopy and scanning probe microscopies, we have systematically studied hydrogen-terminated Si(100) surfaces. These surfaces were obtained by varying the solutions for removal of the chemical oxide grown during the SC1 cleaning step. We find that the smoothest surfaces are obtained using an acidic HF solution containing an oxidizing agent such as H 2 O 2 . Surfaces treated in an HF:H 2 O 2 =1:9 solution exhibited an FT-IR-ATR spectrum dominated by the asymmetric=SiH 2 stretching mode, while scanning probe microscopy studies verified the formation of parallel steps on such surfaces. On the other hand, a basic solution such as NH 4 F resulted in locally rougher surfaces. For such surfaces, we observed a correlation between the degree of - SiH 3 termination and the number of round structures on the Si(100) surface.