Semiconductor memory device
View Patent ↗In order to decrease the circuit scale of a power supply circuit and the area occupied by the power supply circuit over a semiconductor substrate, the power supply circuit, which supplies a supply voltage to respective parts of a memory circuit, includes a word driver power supply (first power supply circuit), a sense amplifier power supply (second power supply circuit), a bit line precharge power supply, a cell plate power supply, a substrate bias power supply, and a word line bias power supply. The word driver power supply supplies a word driver with a voltage generated by directly increasing an external supply voltage, whereas the other power supplies (e.g., the sense amplifier power supply) supply a sense amplifier, etc., with a voltage generated by decreasing the external supply voltage.
1. A semiconductor memory device, comprising:
a plurality of memory cells for storing information by storing an electric charge;
an access transistor having one source/drain terminal connected to the memory cell and the other source/drain terminal connected to a bit line;
a word line connected to a gate terminal of the access transistor;
a sense amplifier for amplifying a voltage of the bit line;
a first power supply circuit for generating a first supply voltage which is used for driving the word line; and
a second power supply circuit for generating a second supply voltage which is used for driving the sense amplifier,
wherein the first power supply circuit increases a supply voltage supplied from an external power supply,
the second power supply circuit decreases the supply voltage supplied from the external power supply
the sense amplifier includes a sense amplifier transistor;
the access transistor and the sense amplifier transistor are formed by transistors having gate insulating films of different thicknesses; and
the gate insulating film of the access transistor is thicker than that of the sense amplifier transistor.
2. A semiconductor memory device, comprising:
a plurality of memory cells for storing information by storing an electric charge;
an access transistor having one source/drain terminal connected to the memory cell and the other source/drain terminal connected to a bit line;
a word line connected to a gate terminal of the access transistor;
a sense amplifier for amplifying a voltage of the bit line;
a first power supply circuit for generating a first supply voltage which is used for driving the word line; and
a second power supply circuit for generating a second supply voltage which is used for driving the sense amplifier,
wherein the first power supply circuit increases a supply voltage supplied from an external power supply,
the second power supply circuit decreases the supply voltage supplied from the external power supply, and
the first power supply circuit has a temperature characteristic such that the first supply voltage increases as the temperature decreases.
3. A semiconductor memory device, comprising:
a plurality of memory cells for storing information by storing an electric charge;
an access transistor having one source/drain terminal connected to the memory cell and the other source/drain terminal connected to a bit line;
a word line connected to a gate terminal of the access transistor;
a sense amplifier for amplifying a voltage of the bit line;
a first power supply circuit for generating a first supply voltage which is used for driving the word line;
a second power supply circuit for generating a second supply voltage which is used for driving the sense amplifier; and
a third power supply circuit which decreases the supply voltage supplied from the external power supply to apply the decreased voltage to the bit line as a precharge voltage and to a common counter electrode of the memory cell as a common counter electrode voltage,
wherein the first power supply circuit increases a supply voltage supplied from an external power supply, and
the second power supply circuit decreases the supply voltage supplied from the external power supply.
4. The semiconductor memory device of claim 3 , wherein the third power supply circuit is formed by connecting outputs of a plurality of power supply circuits to each other.
5. A semiconductor memory device, comprising:
a plurality of memory cells for storing information by storing an electric charge;
an access transistor having one source/drain terminal connected to the memory cell and the other source/drain terminal connected to a bit line;
a word line connected to a gate terminal of the access transistor;
a sense amplifier for amplifying a voltage of the bit line;
a first power supply circuit for generating a first supply voltage which is used for driving the word line;
a second power supply circuit for generating a second supply voltage which is used for driving the sense amplifier; and
a third power supply circuit which decreases the supply voltage supplied from the external power supply to apply the decreased voltage to the word line as a bias voltage and to a substrate of the access transistor as a bias voltage,
wherein the first power supply circuit increases a supply voltage supplied from an external power supply, and
the second power supply circuit decreases the supply voltage supplied from the external power supply.
6. The semiconductor memory device of claim 5 , wherein the third power supply circuit is formed by connecting outputs of a plurality of power supply circuits to each other.
7. A semiconductor memory device, comprising:
a plurality of memory cells for storing information by storing an electric charge;
an access transistor having one source/drain terminal connected to the memory cell and the other source/drain terminal connected to a bit line;
a word line connected to a gate terminal of the access transistor;
a sense amplifier for amplifying a voltage of the bit line;
a first power supply circuit for generating a first supply voltage which is used for driving the word line; and
a second power supply circuit for generating a second supply voltage which is used for driving the sense amplifier,
wherein the first power supply circuit increases a supply voltage supplied from an external power supply,
the second power supply circuit decreases the supply voltage supplied from the external power supply,
a memory circuit including the memory cell and a logic circuit having a function associated with the memory circuit are provided in different regions on the same semiconductor substrate, and
the first power supply circuit and the second power supply circuit are provided in the region in which the logic circuit is provided.
8. A semiconductor memory device, comprising:
a plurality of memory cells for storing information by storing an electric charge;
an access transistor having one source/drain terminal connected to the memory cell and the other source/drain terminal connected to a bit line;
a word line connected to a gate terminal of the access transistor;
a sense amplifier for amplifying a voltage of the bit line;
a first power supply circuit for generating a first supply voltage which is used for driving the word line; and
a second power supply circuit for generating a second supply voltage which is used for driving the sense amplifier,
wherein the first power supply circuit increases a supply voltage supplied from an external power supply,
the second power supply circuit decreases the supply voltage supplied from the external power supply,
a plurality of memory circuits each including a plurality of memory cells are provided on the same semiconductor substrate, and
the first power supply circuit and the second power supply circuit respectively supply the first supply voltage and the second supply voltage commonly to the plurality of memory circuits.
9. A semiconductor memory device, comprising:
a plurality of memory cells for storing information by storing an electric charge;
an access transistor having one source/drain terminal connected to the memory cell and the other source/drain terminal connected to a bit line;
a word line connected to a gate terminal of the access transistor;
a sense amplifier for amplifying a voltage of the bit line;
a first power supply circuit for generating a first supply voltage which is used for driving the word line; and
a second power supply circuit for generating a second supply voltage which is used for driving the sense amplifier,
wherein the first power supply circuit increases a supply voltage supplied from an external power supply,
the second power supply circuit decreases the supply voltage supplied from the external power supply, and
the first power supply circuit and the second power supply circuit respectively control the first supply voltage and the second supply voltage to be kept constant irrespective of a variation in the supply voltage supplied from the external power supply.
10. The semiconductor memory device of claim 9 , wherein the first power supply circuit and the second power supply circuit respectively control the first supply voltage and the second supply voltage based on a common reference voltage.