Patent ID: 7812621

Claim:
A measuring apparatus measuring surface capacitance of an insulating film of a measurement sample structured such that the insulating film is formed on a semiconductor substrate, comprising: a measuring unit measuring a current-voltage characteristic, which is dependency on a dc voltage of a current flowing between a probe and the insulating film, when the dc voltage is applied to the semiconductor substrate while a level of the dc voltage being changed at a desired change speed, the dc voltage causing an inversion layer to be formed on an interface between the semiconductor substrate and the insulating film; and an arithmetic unit obtaining a relationship between a voltage change speed that is a change speed of the voltage applied to insulating film and a saturation current flowing through the insulating film on the basis of the measured current-voltage characteristic, and calculating the surface capacitance of the insulating film on the basis of the obtained relationship, wherein: the measuring unit performs a measurement process measuring a plurality of the current-voltage characteristics by changing the voltage change speed to a plurality of voltage change speeds; and the arithmetic unit detecting a plurality of saturation currents on the basis of the measured plurality of the current-voltage characteristics, plotting a relationship between the detected plurality of saturation currents and the plurality of current-voltage characteristics to obtain a straight line showing a relationship between the saturation current flowing through the insulating film and the voltage change speed, and performing an arithmetic process calculating a slope of the obtained straight line as the surface capacitance of the insulating film.