Threshold voltage measurement device

Abstract

A threshold voltage measurement device is disclosed. The device is coupled to a 6T SRAM. The SRAM comprises two inverters each coupled to a FET. Power terminals of one inverter are in a floating state; the drain and source of the FET coupled to the inverter are short-circuited. Two voltage selectors, a resistor, an amplifier and the SRAM are connected in a negative feedback way. Different bias voltages are applied to the SRAM for measuring threshold voltages of two FETs of the other inverter and the FET coupled to the other inverter. The present invention uses a single circuit to measure the threshold voltages of the three FETs without changing the physical structure of the SRAM. Thereby is accelerated the measurement and decreased the cost of the fabrication process and measurement instruments.