In Situ Electrochemical ATR-FTIR Spectroscopic Investigation of Hydrogen-Terminated Si(110) Surface in Dilute NH[sub 4]F Solution

In situ electrochemical attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy has been employed to study the dependence of hydride structures on a Si(110) surface in dilute NH4F solution. In situ ATR-FTIR results show that the Si(110) surface remains H-terminated in dilute NH4F solution and the hydride on Si(110) has a strong interaction with water molecules under cathodic potential control. In addition, SiHO3 is formed even at cathodic potentials. Infrared roughness factors, defined as the ratio of monohydride at steps or dihydride over the monohydride on the (110) plane, suggest that monohydride-terminated (111) facets are the dominant defects on the Si(110) surface in dilute NH4F solution at cathodic electrode potential. At anodic potential, vertical dihydrides, besides (111) facets, increased on the Si(110) surface leading to a roughened morphology. (C) 2001 The Electrochemical Society.