Surface roughness induced scattering and band tailing

A random potential due to surface roughness has long been recognized as the dominant scattering mechanism at high electron concentrations in quantized inversion layers of semiconductors, but little definitive understanding is truly available. Here, the extent of band tailing and the role of this band tailing in electron transport have been estimated from the second-order correction to the surface subbands arising from the surface roughess induced random potential. Surface roughness parameters were determined from high resolution TEM pictures of the Si-SiO2 interface and are found to be in reasonable agreement with earlier estimates. Calculations based upon these parameters indicate that band tailing is important at high inversion layer densities (≳ 1012cm2).