Patent ID: 6111423
Filing Date: 2000-08-29
Classification: G01R

Abstract:
A pinch-off voltage measurement circuit for measuring a pinch-off voltage of a field effect transistor, said circuit comprising:a measuring means,a measuring capacitor, anda connection circuit,wherein,said measuring means applies a voltage to said field effect transistor and detects a change of impedance with respect to the applied voltage via said connection circuit for measuring the pinch-off voltage of said field effect transistor, andsaid connection circuit comprises:a first detection terminal and second detection terminal to which said measuring means is connected, one side of a measuring capacitor being connected to one of said detection terminals;a first element connection terminal to which one of the source and drain of said field effect transistor is connected;a second element connection terminal to which the other of the source and drain is connected; anda third element connection terminal to which the gate is connected, the one detection terminal to which said measuring capacitor is connected and the third element connection terminal being short-circuited, an opposite side of said measuring capacitor being connected to one of said first element connection terminal and said second element connection terminal and having a capacitance value sufficiently larger than the transistor capacitance between the source or drain and the gate in said field effect transistor.