Semiconductor memory and system
A semiconductor memory includes a real memory cell including a selection transistor and a resistance variable element which are connected in series between a first voltage line and a second voltage line through a connection node, a real amplification transistor having a gate connected to the connection node, a source connected to a reference voltage line, and a drain connected to a real read line, and a sense amplifier to determine a logic held in the real memory cell by receiving a voltage of the real read line varied with a voltage generated in the connection node by resistance dividing between a source/drain resistance of the selection transistor, and the resistance variable element, the selection transistor receiving a read control voltage at the gate thereof.
1. A semiconductor memory, comprising:
a memory cell including a selection transistor and a resistance variable element which are connected in series between a first voltage line and a second voltage line through a connection node, and an amplification transistor having a gate connected to the connection node, a source connected to a reference voltage line, and a drain connected to a read line;
a sense amplifier to determine a logic held in the memory cell by receiving a voltage of the read line varied with a voltage generated in the connection node by resistance dividing between a source/drain resistance of the selection transistor and the resistance variable element, the selection transistor receiving a read control voltage at the gate thereof;
a control circuit to set a word line connected to the gate of the selection transistor to the read control voltage in a read operation, set the first voltage line to a high-level voltage, and set the second voltage line to a low-level voltage; and
a pre-charge circuit to temporally supply a pre-charge voltage to the read line before the word line is set to the read control voltage in the read operation.
2. The semiconductor memory according to claim 1 , wherein
the control circuit sets the voltage of the word line in a read operation to not be higher than the voltage of the word line in a write operation.
3. The semiconductor memory according to claim 1 , wherein
the pre-charge circuit sets the voltage of the read line to be equal to the reference voltage line in a write operation.
4. The semiconductor memory according to claim 1 , further comprising:
a reference memory cell connected to the first voltage line and the second voltage line, wherein
the reference memory cell includes:
a first selection transistor and a first resistance variable element having a resistance value set to a low-resistance state, which are connected in series between a first voltage line and a second voltage line through a first connection node;
a first amplification transistor having a gate connected to the first connection node, a source connected to the reference voltage line, and a drain connected to a reference read line, where a gate width is formed so that the gate size is the half of the amplification transistor;
a second selection transistor and a second resistance variable element having a resistance value set to a high-resistance state, which are connected in series between the first voltage line and the second voltage line through a second connection node;
a second amplification transistor having a gate connected to the second connection node, a source connected to the reference voltage line, and a drain connected to a reference read line, where a gate width is formed so that the gate size is the half of the amplification transistor, wherein
the sense amplifier includes a differential input pair connected to the read line and the reference read line, and determines logic held in the memory cell in response to the voltage of the read line and the voltage of the reference read light, which are changed in a read operation.
5. The semiconductor memory according to claim 4 , further comprising:
a control circuit to set, in a read operation, a word line connected to the gate of the selection transistor, a first reference word line connected to the gate of the first selection transistor, and second reference word line connected to the gate of the second transistor to the read control voltage, set the first voltage line to a high level voltage, and set the second voltage line to a low level voltage; and
a pre-charge circuit to temporally supply a pre-charge voltage to the read line and the reference read line before the word line and the first and second reference word line are set to the read control voltage.
6. The semiconductor memory according to claim 4 , wherein
the sense amplifier includes a first current mirror circuit connected to the read line and a second current mirror circuit connected to the reference read line, wherein a current pair output from the first current mirror circuit and the second current mirror circuit is received by the differential input pair.
7. The semiconductor memory according to claim 4 , further comprising:
a first memory block and a second memory block, each including the memory cell and the reference memory cell,
wherein
in the first memory block, the read line connected to the memory cell and the reference read line connected to the reference memory cell are connected to a first read line, and
in the second memory block, the read line connected to the memory cell and the reference read line connected to the reference memory cell are connected to a second read line, wherein
the differential input pair of the sense amplifier is connected to the first read line and the second read line.
8. The semiconductor memory according to claim 1 , further comprising:
a plurality of memory blocks each including the memory cell, the sense amplifier, the control circuit, and the pre-charge circuit; and
a voltage-generating section to generate the read control voltage, which is formed corresponding to each of the memory blocks.
9. The semiconductor memory according to claim 1 , wherein
the resistance variable element of the memory cell is a magnetic tunnel junction element formed on a magnetic random access memory (MRAM).
10. The semiconductor memory according to claim 9 , further comprising:
a write word line arranged adjacent to the magnetic tunnel junction element, where the write word line intersects the second voltage line.
11. The semiconductor memory according to claim 1 , wherein
the resistance variable element of the memory cell is a resistance variable element formed in a phase change random access memory (PRAM).
12. The semiconductor memory according to claim 1 , wherein
the resistance variable element of the memory cell is a resistance variable element formed in resistive random a access memory (ReRAM).
13. A system, comprising:
a semiconductor memory including,
a selection transistor and a resistance variable element which are connected in series between a first voltage line and a second voltage line through a connection node;
a amplification transistor having a gate connected to the connection node, a source connected to a reference voltage line, and a drain connected to a read line;
a sense amplifier to determine a logic held in the memory cell by receiving a voltage of the read line varied with a voltage generated in the connection node by resistance dividing between a source/drain resistance of the selection transistor and the resistance variable element, the selection transistor receiving a read control voltage at the gate thereof;
a controller to control access to the semiconductor memory;
a control circuit to set a word line connected to the gate of the selection transistor to the read control voltage in a read operation, set the first voltage line to a high-level voltage, and set the second voltage line to a low-level voltage; and
a pre-charge circuit to temporally supply a pre-charge voltage to the read line before the word line is set to the read control voltage in the read operation.
14. A system, comprising:
a semiconductor memory including,
a selection transistor and a resistance variable element which are connected in series between a first voltage line and a second voltage line through a connection node;
a amplification transistor having a gate connected to the connection node, a source connected to a reference voltage line, and a drain connected to a read line;
a sense amplifier to determine a logic held in the memory cell by receiving a voltage of the read line varied with a voltage generated in the connection node by resistance dividing between a source/drain resistance of the selection transistor and the resistance variable element, the selection transistor receiving a read control voltage at the gate thereof;
a controller to control access to the semiconductor memory;
a reference memory cell connected to the first voltage line and the second voltage line, wherein the reference memory cell includes,
a first selection transistor and a first resistance variable element having a resistance value set to a low-resistance state, which are connected in series between a first voltage line and a second voltage line through a first connection node;
a first amplification transistor having a gate connected to the first connection node, a source connected to the reference voltage line, and a drain connected to a reference read line, where a gate width is formed so that the gate size is the half of the amplification transistor;
a second selection transistor and a second resistance variable element having a resistance value set to a high-resistance state, which are connected in series between the first voltage line and the second voltage line through a second connection node;
a second amplification transistor having a gate connected to the second connection node, a source connected to the reference voltage line, and a drain connected to a reference read line, where a gate width is formed so that the gate size is the half of the amplification transistor, wherein
the sense amplifier includes a differential input pair connected to the read line and the reference read line, and determines logic held in the memory cell in response to the voltage of the read line and the voltage of the reference read light, which are changed in a read operation.
15. The system according to claim 14 , wherein
the semiconductor memory further includes:
a word line connected to the gate of the selection transistor, a first reference word line connected to the gate of the first selection transistor, and second reference word line connected to the gate of the second transistor to the read control voltage, the first voltage line is set to a high level voltage, and the second voltage line is set to a low level voltage;
a pre-charge circuit to temporally supply a pre-charge voltage to the read line and the reference read line before the word line and the first and second reference word line are set to the read control voltage.
16. The system according to claim 14 , wherein
the sense amplifier includes a first current mirror circuit connected to the read line and a second current mirror circuit connected to the reference read line, wherein
a current pair output from the first current mirror circuit and the second current mirror circuit is received by the differential input pair.
17. The system according to claim 14 , wherein
the semiconductor memory further includes:
a first memory block and a second memory block, each including the memory cell and the reference memory cell, wherein
in the first memory block, the read line connected to the memory cell and the reference read line connected to the reference memory cell are connected to a first read line,
in the second memory block, the read line connected to the memory cell and the reference read line connected to the reference memory cell are connected to a first read line, and
the differential input pair of the sense amplifier is connected to the first read line and the second read line.
18. The system according to claim 13 , wherein
the semiconductor memory further includes:
a plurality of memory blocks each including the memory cell, the sense amplifier, the control circuit, and the pre-charge circuit; and
a voltage-generating section to generate the read control voltage, which is formed corresponding to each of the memory blocks.