Changes in dopant concentration profiles in crystalline silicon induced by rf hydrogen plasma treatment of Si-SiO2structures were studied by using differential capacitance technique. It was found that such a treatment influences p-type and n-type silicon controversially. In p-type Si compensation of boron acceptors by neutral H-B complex formation was observed. It was suggested that the increase of doping concentration in n-type Si is due to the generation of donor-like defects in the bulk Si by plasma radiation.