A semiconductor device including a conductive substrate or a first conductive layer formed on the substrate, a non-single-crystal semiconductor layer member is disposed on the conductive substrate or the conductive layer, the non-single-crystal semiconductor layer member having at least one intrinsic, non-single-crystal semiconductor layer, and a second conductive layer disposed on the non-single-crystal semiconductor layer. The intrinsic non-single-crystal semiconductor layer contains sodium and oxygen in very low concentrations where each concentration is 510¹⁸ atoms/cm³ or less.