Semiconductor device and method for driving semiconductor device

A method for driving a semiconductor device including a first transistor whose channel region includes an oxide semiconductor, a second transistor, a third transistor, and a capacitor whose one electrode electrically connected to one of a source and a drain of the first transistor and a gate of the second transistor, the method comprising:

• applying a low voltage to a bit line and a first wiring, applying a high voltage to a first word line to turn on the first transistor, applying the low voltage of the bit line to the gate of the second transistor to turn on the second transistor, and applying a low voltage to a second word line to turn on the third transistor, wherein:
• the first word line is electrically connected to a gate of the first transistor,
• the second word line is electrically connected to a gate of the third transistor,
• the first wiring is electrically connected to one of a source and a drain of the second transistor
• one of a source and a drain of the third transistor is electrically connected to the other of the source and the drain of the second transistor,
• the bit line is electrically connected to the other of the source and the drain of the first transistor and the other of the source and the drain of the third transistor, and
• a low voltage is applied to the other electrode of the capacitor;
• applying a first voltage to the first wiring, and stopping the application of the low voltage to the bit line so that a voltage corresponding to the first voltage is applied to the gate of the second transistor from the first wiring through the source and the drain of the second transistor, the source and the drain of the third transistor, the bit line, and the source and the drain of the first transistor;
• applying a low voltage to the first word line to turn off the first transistor, applying a low voltage to the bit line and the first wiring, and applying a high voltage to the second word line to turn off the third transistor;
• applying a high voltage to the first wiring;
• and
• stopping the application of the high voltage to the first wiring, and applying a low voltage to the second word line to turn on the third transistor so that a voltage of the first wiring changes from the high voltage to the first voltage.

A method for driving a semiconductor device including a first transistor whose channel region includes an oxide semiconductor, a second transistor, and a capacitor whose one electrode electrically connected to one of a source and a drain of the first transistor and a gate of the second transistor, the method comprising:

• applying a high voltage to a bit line and a first wiring, applying a high voltage to a word line to turn on the first transistor, and applying a high voltage to a capacitor line, thereby turning on the second transistor, wherein:
• the word line is electrically connected to a gate of the first transistor,
• the first wiring is electrically connected to one of a source and a drain of the second transistor,
• the bit line is electrically connected to the other of the source and the drain of the first transistor and the other of the source and the drain of the second transistor, and
• the capacitor line is electrically connected to the other electrode of the capacitor;
• applying a first voltage to the first wiring and stopping application of the high voltage to the bit line so that a voltage corresponding to the first voltage is applied to the gate of the second transistor from the first wiring through the source and the drain of the second transistor, the bit line, and the source and the drain of the first transistor;
• applying a low voltage to the word line to turn off the first transistor, applying a high voltage to the bit line and the first wiring, and applying a low voltage to the capacitor line to turn off the second transistor;
• applying a low voltage to the first wiring;
• and
• stopping the application of the low voltage to the first wiring, and applying a high voltage to the capacitor line so that a voltage of the first wiring changes from the low voltage to the first voltage.

A method for driving a semiconductor device including a first transistor whose channel region includes an oxide semiconductor, a second transistor, a third transistor, and a capacitor whose one electrode electrically connected to one of a source and a drain of the first transistor and a gate of the second transistor, the method comprising:

• applying a high voltage to a bit line and a first wiring, applying a high voltage to a first word line to turn on the first transistor, applying the high voltage of the bit line to the gate of the second transistor to turn on the second transistor, and applying a high voltage to a second word line to turn on the third transistor, wherein:
• the first word line is electrically connected to a gate of the first transistor,
• the second word line is electrically connected to a gate of the third transistor,
• the first wiring is electrically connected to one of a source and a drain of the second transistor
• one of a source and a drain of the third transistor is electrically connected to the other of the source and the drain of the second transistor,
• the bit line is electrically connected to the other of the source and the drain of the first transistor and the other of the source and the drain of the third transistor, and
• a low voltage is applied to the other electrode of the capacitor;
• applying a first voltage to the first wiring, and stopping the application of the high voltage to the bit line so that a voltage corresponding to the first voltage is applied to the gate of the second transistor from the first wiring through the source and the drain of the second transistor, the source and the drain of the third transistor, the bit line, and the source and the drain of the first transistor;
• applying a low voltage to the first word line to turn off the first transistor, applying a high voltage to the bit line and the first wiring, and applying a low voltage to the second word line to turn off the third transistor;
• applying a low voltage to the first wiring;
• and
• stopping the application of the low voltage to the first wiring, and applying a high voltage to the second word line to turn on the third transistor so that a voltage of the first wiring changes from the high voltage to the first voltage.