Semiconductor memory device and semiconductor device

• US 8,750,022 B2
• Filed: 04/04/2011
• Issued: 06/10/2014
• Est. Priority Date: 04/09/2010
• Status: Expired due to Fees

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Saito, Toshihiko, Takahashi, Yasuyuki
• Primary Examiner(s): Hoang, Huan
• Assistant Examiner(s): Huang, Min
• Application Number:
  US13/079,032
• Publication Number:
  US 20110249487A1
• Time in Patent Office: 1,163 Days
• Field of Search: 365/189.011
• US Class Current: 365/149
• CPC Class Codes: G11C 7/12 Bit line control circuits, e.g. drivers, boosters, pull-up circuits, pull-down circuits, precharging circuits, equalising circuits, for bit lines
• CPC Class Codes: H01L 27/1214 comprising a plurality of TFTs formed on a non-semiconducting substrate, e.g. driving circuits for AMLCDs
• CPC Class Codes: H10B 20/00 Read-only memory [ROM] devices
• CPC Class Codes: H10B 20/20 Programmable ROM [PROM] devices comprising field-effect components H10B20/10 takes precedence

Abstract

A semiconductor memory device or a semiconductor device which has high reading accuracy is provided. A bit line, a word line, a memory cell placed in an intersection portion of the bit line and the word line, and a reading circuit electrically connected to the bit line are provided. The memory cell includes a first transistor and an antifuse. The reading circuit includes a pre-charge circuit, a clocked inverter, and a switch. The pre-charge circuit includes a second transistor and a NAND circuit. The semiconductor memory device includes transistor in each of which an oxide semiconductor is used in a channel formation region, as the first transistor and the second transistor.

Claims

1. A semiconductor memory device comprising:

a memory cell including a first transistor and a memory element;

a pre-charge circuit including a second transistor;

a clocked inverter; and

a switch,

wherein a gate of the first transistor is electrically connected to a first line, one of a source and a drain of the first transistor is electrically connected to a second line, and the other of the source and the drain of the first transistor is electrically connected to one electrode of the memory element,

wherein one of a source and a drain of the second transistor is electrically connected to a third line, and the other of the source and the drain of the second transistor is electrically connected to one terminal of the switch and an input terminal of the clocked inverter,

wherein an output terminal of the clocked inverter is electrically connected to an output signal line,

wherein the other terminal of the switch is electrically connected to the second line,

wherein a channel formation region of the first transistor and a channel formation region of the second transistor each include an oxide semiconductor, and

wherein an off current value of the first transistor is lower than or equal to 10 aA/μ

m.

2. The semiconductor memory device according to claim 1,

wherein the pre-charge circuit further includes a NAND circuit,

wherein a gate of the second transistor is electrically connected to an output terminal of the NAND circuit,

wherein one input terminal of the NAND circuit is electrically connected to an address signal line, and

wherein the other input terminal of the NAND circuit is electrically connected to a pre-charge signal line.

3. The semiconductor memory device according to claim 1,

wherein the memory cell further includes a capacitor,

wherein the other of the source and the drain of the first transistor is electrically connected to one electrode of the capacitor.

4. The semiconductor memory device according to claim 1, wherein the second line is pre-charged by the pre-charge circuit before performing reading operation of the memory cell.

5. The semiconductor memory device according to claim 1, wherein the third line is a power supply line, and the second line is pre-charged with a power supply potential inputted from the power supply line by the pre-charge circuit.

6. A semiconductor device comprising the semiconductor memory device according to claim 1.

7. A semiconductor memory device comprising:

m first lines (m is an integer of 1 or more);

n second lines (n is an integer of 1 or more);

(m×

n) memory cells, each one of the (m×

n) memory cells includes a first transistor and a memory element;

m reading circuits, each one of m reading circuits is electrically connected to a corresponding one of the m first lines, each one of the m reading circuits including;

a pre-charge circuit including a second transistor; and

a switch, and

a latch circuit electrically connected to the m reading circuits,

wherein a gate of the first transistor is electrically connected to a corresponding one of the n second lines, one of a source and a drain of the first transistor is electrically connected to a corresponding one of the m first lines, and the other of the source and the drain of the first transistor is electrically connected to one electrode of the memory element,

wherein one of a source and a drain of the second transistor is electrically connected to a third line, and the other of the source and the drain of the second transistor is electrically connected to one terminal of the switch and an input terminal of the latch circuit,

wherein an output terminal of the latch circuit is electrically connected to an output signal line,

wherein the other terminal of the switch is electrically connected to the one of the source and the drain of the first transistor,

wherein a channel formation region of the first transistor and a channel formation region of the second transistor each include an oxide semiconductor, and

wherein an off current value of the first transistor is lower than or equal to 10 aA/μ

m.

8. The semiconductor memory device according to claim 7,

wherein the pre-charge circuit further includes a NAND circuit,

wherein a gate of the second transistor is electrically connected to an output terminal of the NAND circuit,

wherein one input terminal of the NAND circuit is electrically connected to an address signal line, and

wherein the other input terminal of the NAND circuit is electrically connected to a pre-charge signal line.

9. The semiconductor memory device according to claim 7,

wherein the each one of the (m×

n) memory cells further includes a capacitor,

wherein the other of the source and the drain of the first transistor is electrically connected to one electrode of the capacitor.

10. The semiconductor memory device according to claim 7, wherein reading of memory cells electrically connected to the same first line is performed at the same time.

11. The semiconductor memory device according to claim 10, wherein the m first lines are pre-charged by the pre-charge circuit included in the m reading circuits before performing reading operation.

12. The semiconductor memory device according to claim 7, wherein the third line is a power supply line, and corresponding one of the m first lines is pre-charged with a power supply potential inputted from the power supply line by the pre-charge circuit.

13. A semiconductor device comprising the semiconductor memory device according to claim 7.

14. A semiconductor memory device comprising:

a memory cell including a first transistor and a memory element;

a pre-charge circuit including a second transistor;

a clocked inverter; and

a switch,

wherein a gate of the first transistor is electrically connected to a first line, one of a source and a drain of the first transistor is electrically connected to a second line, and the other of the source and the drain of the first transistor is electrically connected to one electrode of the memory element,

wherein one of a source and a drain of the second transistor is electrically connected to a third line, and the other of the source and the drain of the second transistor is electrically connected to one terminal of the switch and an input terminal of the clocked inverter,

wherein an output terminal of the clocked inverter is electrically connected to an output signal line,

wherein the other terminal of the switch is electrically connected to the second line,

wherein a channel formation region of the first transistor and a channel formation region of the second transistor each include an oxide semiconductor,

wherein an off current value of the first transistor is lower than or equal to 10 aA/μ

m, and

wherein the second line is configured to be charged by the pre-charge circuit before performing reading operation of the memory cell.

15. The semiconductor memory device according to claim 14,

wherein the pre-charge circuit further includes a NAND circuit,

wherein a gate of the second transistor is electrically connected to an output terminal of the NAND circuit,

wherein one input terminal of the NAND circuit is electrically connected to an address signal line, and

wherein the other input terminal of the NAND circuit is electrically connected to a pre-charge signal line.

16. The semiconductor memory device according to claim 14,

wherein the memory cell further includes a capacitor,

wherein the other of the source and the drain of the first transistor is electrically connected to one electrode of the capacitor.

17. The semiconductor memory device according to claim 14, wherein the third line is a power supply line, and the second line is pre-charged with a power supply potential inputted from the power supply line by the pre-charge circuit.

18. A semiconductor device comprising the semiconductor memory device according to claim 14.

25. The semiconductor memory device according to claim 14, wherein the memory element is an antifuse.

19. A semiconductor memory device comprising:

m first lines (m is an integer of 1 or more);

n second lines (n is an integer of 1 or more);

(m×

n) memory cells, each one of the (m×

n) memory cells includes a first transistor and a memory element;

m reading circuits electrically connected to a corresponding one of the m first lines, each one of the m reading circuits including;

a pre-charge circuit including a second transistor; and

a switch, and

a latch circuit electrically connected to the m reading circuits,

wherein a gate of the first transistor is electrically connected to a corresponding one of the n second lines, one of a source and a drain of the first transistor is electrically connected to a corresponding one of the m first lines, and the other of the source and the drain of the first transistor is electrically connected to one electrode of the memory element,

wherein one of a source and a drain of the second transistor is electrically connected to a third line, and the other of the source and the drain of the second transistor is electrically connected to one terminal of the switch and an input terminal of the latch circuit,

wherein an output terminal of the latch circuit is electrically connected to an output signal line,

wherein the other terminal of the switch is electrically connected to the one of the source and the drain of the first transistor,

wherein a channel formation region of the first transistor and a channel formation region of the second transistor each include an oxide semiconductor,

wherein an off current value of the first transistor is lower than or equal to 10 aA/μ

m, and

wherein each one of the m first lines is configured to be charged by a corresponding one of m pre-charge circuits before performing reading operation of a corresponding one of (m×

n) memory cells.

20. The semiconductor memory device according to claim 19,

wherein the pre-charge circuit further includes a NAND circuit,

wherein a gate of the second transistor is electrically connected to an output terminal of the NAND circuit,

wherein one input terminal of the NAND circuit is electrically connected to an address signal line, and

wherein the other input terminal of the NAND circuit is electrically connected to a pre-charge signal line.

21. The semiconductor memory device according to claim 19,

wherein the each one of the (m×

n) memory cells further includes a capacitor,

wherein the other of the source and the drain of the first transistor is electrically connected to one electrode of the capacitor.

22. The semiconductor memory device according to claim 19, wherein reading of memory cells electrically connected to the same first line is performed at the same time.

23. The semiconductor memory device according to claim 19, wherein the third line is a power supply line, and corresponding one of the m first lines is pre-charged with a power supply potential inputted from the power supply line by the pre-charge circuit.

24. A semiconductor device comprising the semiconductor memory device according to claim 19.

26. The semiconductor memory device according to claim 19, wherein the memory element is an antifuse.