Semiconductor device and method for driving the same

A semiconductor device, comprising:

• a control-voltage supply unit;
• a field-effect transistor including a gate electrode having a function of accumulating a charge;
• and
• a capacitor and a resistor, disposed in parallel and interposed between the control-voltage supply unit and the gate electrode,
• wherein the semiconductor device can store multilevel information.

A method for driving a semiconductor device including a control-voltage supply unit, a field-effect transistor including a gate electrode having a function of accumulating a charge, a capacitor, and a resistor, the capacitor and the resistor being disposed in parallel and interposed between the control-voltage supply unit and the gate electrode,

• the method comprising the steps of:
• a) applying a write voltage to both ends of the resistor to vary the amount of the charge accumulated in the gate electrode via the resistor, thereby changing a threshold voltage of the field-effect transistor;
• and
• b) reading out information according to variation in a drain current in the field-effect transistor.