Silicon nanowires are patterned down to 30 nm using complementary metal-oxide-semiconductor (CMOS) compatible process. The electrical conductivities of n-/p-leg nanowires are extracted with the variation of width. Using this structure, Seebeck coefficients are measured. The obtained maximum Seebeck coefficient values are 122 mu V/K for p-leg and -94 mu V/K for n-leg. The maximum attainable power factor is 0.74 mW/m K(2) at room temperature.