Nonvolatile semiconductor memory

1. A nonvolatile semiconductor memory comprising:

a resistance-change element having first and second terminals;

a transistor having third and fourth terminals and a control terminal, the third terminal being electrically connected to the second terminal;

a driver electrically connected to the first and fourth terminals, applying one of a first potential and a second potential to the first terminal and the other of the first and second potentials to the fourth terminal in writing, and applying one of the first and second potentials to the first terminal and the other of the first and second potentials to the fourth terminal in reading; and

a circuit electrically connected between the first and fourth terminals, and changing potentials of the first and fourth terminals to a third potential between the first and second potentials in the reading.

2. The memory of claim 1 , further comprising:

a circuit discharging one of the first and fourth terminals which have the third potential in the reading.

3. The memory of claim 2 , further comprising:

a decoder applying a fourth potential for turning on the transistor to the control terminal in a state in which one of the first and fourth terminals is discharged and the other of the first and fourth terminals holds the third potential in the reading.

4. The memory of claim 3 , further comprising:

a sense amplifier electrically connected to one of the first and fourth terminals and sensing data stored in the resistance-change element.

5. The memory of claim 1 , wherein

the first potential is larger than the second potential.

6. The memory of claim 1 , wherein

the second potential is larger than the first potential.

7. The memory of claim 1 , wherein

one of the first and second potentials is a write potential, and the third potential is a read potential.

8. The memory of claim 1 , wherein

the driver is a write driver.

9. The memory of claim 1 , wherein

the resistance-change element is a magnetoresistive element.

10. The memory of claim 1 , wherein

the circuit changes potentials of the first and fourth terminals to the third potential before sensing.

11. A nonvolatile semiconductor memory comprising:

a resistance-change element having first and second terminals;

a transistor having third and fourth terminals and a control terminal, the third terminal being electrically connected to the second terminal;

a driver electrically connected to the first and fourth terminals, applying one of a first potential and a second potential to the first terminal and the other of the first and second potentials to the fourth terminal in writing, and applying one of the first and second potentials to the first terminal and the other of the first and second potentials to the fourth terminal in reading; and

a node set to be a fourth potential,

wherein the circuit produces the third potential by shorting the first terminal, the fourth terminal and the node in the reading.

12. The memory of claim 11 , wherein

the first and fourth terminals are connected to first and second bit lines, respectively, and the node is connected to a third bit line.

13. The memory of claim 11 , wherein

the first and fourth terminals are connected to first and second bit lines, respectively, and the node is connected to a global bit line connected to one of the first and second bit lines.

14. The memory of claim 13 , wherein

the fourth potential is held in a capacitance connected to the global bit line.

15. The memory of claim 11 , wherein

the fourth potential is substantially equal to the first potential.

16. The memory of claim 11 , wherein

the fourth potential is substantially equal to the second potential.

17. The memory of claim 11 , wherein

the fourth potential is different from the first and second potentials.

18. A nonvolatile semiconductor memory comprising:

a resistance-change element having first and second terminals;

a transistor having third and fourth terminals and a control terminal, the third terminal being electrically connected to the second terminal;

a driver electrically connected to the first and fourth terminals, applying one of a first potential and a second potential to the first terminal and the other of the first and second potentials to the fourth terminal in writing, and applying one of the first and second potentials to the first terminal and the other of the first and second potentials to the fourth terminal in reading;

a first capacitance electrically connected to the first terminal and holding one of the first and second potentials in the reading; and

a second capacitance electrically connected to the fourth terminal and holding the other of the first and second potentials in the reading.

19. A nonvolatile semiconductor memory comprising:

a resistance-change element having first and second terminals;

a transistor having third and fourth terminals and a control terminal, the third terminal being electrically connected to the second terminal;

a driver electrically connected to the first and fourth terminals, applying one of a first potential and a second potential to the first terminal and the other of the first and second potentials to the fourth terminal in writing, and applying one of the first and second potentials to the first terminal and the other of the first and second potentials to the fourth terminal in reading;

first and second capacitances electrically connected to the first terminal and holding one of the first and second potentials in the reading; and

third and fourth capacitances electrically connected to the fourth terminal and holding the other of the first and second potentials in the reading.

20. The memory of claim 19 , further comprising:

first and second memory cells each including the resistance-change element and the transistor,

wherein data stored in the first memory cell is read by using the first and second potentials held in the first and third capacitances, and data stored in the second memory cell is read by using the first and second potentials held in the second and fourth capacitances.