The paper describes the behavior of capacitance (C-V) and conductance (G/omega-V) versus voltage characteristics of Ag/SnO2/n-Si/Au metal-oxide-semiconductor (MOS) junction under dark and light condition. In addition, C-V of the junction is measured at room temperature for several frequencies. Ag/SnO2/n-Si/Au MOSjunction is fabricated with both spray pyrolysis at kept substrate temperature of 300 degrees C and thermal evaporation in high vacuum processes for the SnO2 layer and metallic contacts respectively. C-V curves present several peaks when SnO2/Si junction is illuminated with high light intensities. The peaks seem to Gaussian distribution within the reverse-forward bias voltage. Under dark room light and solar simulator conditions, the electrical measurements of junction are achieved presenting different behaviors. The carrier density, calculated from C-V measurements of metal oxide semiconductor junction as a function of light intensity, changes from 0.17 x 10(17) to 0.85 x 10(17) cm(-3) as a result of light intensity.