The present disclosure provides a method of analyzing a semiconductor device. The method includes providing a first transistor, a second transistor disposed adjacent to the first transistor, and a gate electrode common to the first transistor and the second transistor; connecting a power-supply voltage (Vdd) to the gate electrode to turn on the first transistor, determining a first threshold voltage (Vth) based on the power-supply voltage; switching the power-supply voltage to a ground voltage (Vss); connecting the ground voltage to the gate electrode to turn on the second transistor; and determining a second threshold voltage based on the ground voltage.