Patent ID: 7573271

Claim:
An apparatus for measuring electric characteristic of a semiconductor comprising: light irradiating means for irradiating light to a characteristic measured semiconductor; an alternating-current voltage source; electrodes for applying an alternating-current voltage to said characteristic measured semiconductor from said alternating-current voltage source; an impedance regulator connected to said characteristic measured semiconductor in series; and electric potential measuring means for measuring electric potential at a connection point between said characteristic measured semiconductor and said impedance regulator, wherein said impedance regulator is regulated so as to have alternating-current impedance similar to that of said characteristic measured semiconductor, said alternating-current voltage being applied to said characteristic measured semiconductor in such a manner that electric potential at said connection point between said characteristic measured semiconductor and said impedance regulator may become zero electric potential, and wherein at least said characteristic measured semiconductor is applied with a direct-current bias voltage, said direct-current bias voltage being applied to said characteristic measured semiconductor in the state in which said alternating-current voltage is superimposed upon said direct-current bias voltage from said alternating-current voltage source.