Galvanomagnetic Effects in Silicon Surface Inversion Layers

In this paper a theory on the galvanomagnetic effect of two-dimensional electron gas in silicon surface inversion layers is presented together with experimental results on the (111) surface of silicon. The calculation takes into account two-dimensional many-valley energy band structure and energy-dependent relaxation time. An expression for the ratio of Hall mobility to conductivity mobility is obtained and the ratio is found to depend on crystal orientations, scattering mechanisms and carrier concentrations. The theory of magnetoresistance is compared with experimental results measured on the (111) surface of silicon at 300°K and 77°K. Validity of the two-dimensional electron gas model for electrons in silicon surface inversion layers is evaluated and it is found that electrons behave neither as two-dimensional nor as three-dimensional gas but as the mixture of them at room temperature.