Patent ID: 6982555

Claim:
A semiconductor device that has a structure in which a semiconductor chip includes a first conductor member, a second conductor member provided with a dielectric interposed between the first conductor member and the second conductor member, a third conductor member provided with a dielectric interposed between each of the first and second conductor members and the third conductor member, and a capacitance measuring circuit, wherein the capacitance measuring circuit comprises: a charging voltage supply part for charging the first conductor member, said charging voltage supply part being connected via a first charge-side switching transistor to the first conductor member; a current sampling part for sampling currents flowing through the second and third conductor members, said current sampling part being connected via first and second switching transistors for measuring current to the second and third conductor members, respectively; and a control circuit for controlling ON/OFF switching of each of the switching transistors, the second conductor member is connected to the charging voltage supply part via a second charge-side switching transistor whose ON/OFF switching is controllable by the control circuit; the third conductor member is connected via a third charge-side switching transistor to the charging voltage supply part; the first conductor member is connected via a third switching transistor for measuring current to the current sampling part; and a switching transistor for decreasing off-leakage current is placed between each of the first through third conductor members and the current sampling part, said switching transistor being connected in series with a corresponding one of the first through third switching transistors for measuring current and having a higher threshold voltage than said corresponding switching transistor for measuring current.