Semiconductor storage device

• US 8,824,193 B2
• Filed: 05/11/2012
• Issued: 09/02/2014
• Est. Priority Date: 05/18/2011
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yoneda, Seiichi
• Primary Examiner(s): Le, Vu
• Application Number:
  US13/469,159
• Publication Number:
  US 20120294066A1
• Time in Patent Office: 844 Days
• Field of Search: 365/149, 365/189.05, 365/189.12
• US Class Current: 365/149
• CPC Class Codes: G11C 19/184 with field-effect transistors, e.g. MOS-FET
• CPC Class Codes: G11C 19/28 using semiconductor elements G11C19/14, G11C19/36 take precedence
• CPC Class Codes: H03K 3/356008 ensuring a predetermined initial state when the supply voltage has been applied; storing the actual state when the supply voltage fails digital storage cells each combining volatile and non-volatile storage properties G11C14/00

Abstract

A semiconductor storage device which stops and resumes the supply of power supply voltage without the necessity of saving and returning a data signal between a volatile storage device and a nonvolatile storage device is provided. In the semiconductor storage device, data is held in a data holding portion connected to a transistor including a semiconductor layer containing an oxide semiconductor and a capacitor. The potential of the data held in the data holding portion is controlled by a data potential holding circuit and a data potential control circuit. The data potential holding circuit can output data without leaking electric charge, and the data potential control circuit can control the potential of the data held in the data holding portion without leaking electric charge by capacitive coupling through the capacitor.

Claims

1. A semiconductor storage device comprising:

a wiring;

a first storage circuit comprising a first transistor, a first capacitor, a first data holding portion, a first circuit, and a first control circuit;

a second storage circuit comprising a second transistor, a second capacitor, a second data holding portion, a second circuit, and a second control circuit; and

a third transistor,

wherein the first storage circuit and the second storage circuit are adjacent to each other,

wherein one of a source and a drain of the first transistor is electrically connected to the wiring,

wherein the first data holding portion is configured to hold data supplied from the wiring when the first transistor and the second transistor are in an Off-state,

wherein the first data holding portion is electrically connected to the other of the source and the drain of the first transistor, a first electrode of the first capacitor, an input terminal of the first circuit, and one of a source and a drain of the second transistor,

wherein the first circuit is configured to output a first signal to the first control circuit and a data output portion, a potential of the first signal depending on a potential of the data in the first data holding portion,

wherein the first control circuit is configured to output a second signal to a second electrode of the first capacitor so that the potential of the data in the first data holding portion is controlled by the second signal,

wherein the second data holding portion is electrically connected to the other of the source and the drain of the second transistor, a first electrode of the second capacitor, an input terminal of the second circuit, and the third transistor, and

wherein the second data holding portion is configured to hold the data supplied from the first data holding portion when the second transistor and the third transistor are in an Off-state.

2. The semiconductor storage device according to claim 1, wherein at least one of the first circuit, the first control circuit, the second circuit, and the second control circuit comprises a transistor comprising a semiconductor including silicon.

3. The semiconductor storage device according to claim 2, wherein the transistor and the first transistor or the second transistor are stacked.

4. The semiconductor storage device according to claim 1, wherein the first to third transistors are each a transistor comprising a semiconductor layer including an oxide semiconductor.

5. The semiconductor storage device according to claim 4, wherein the oxide semiconductor is an In—

Sn—

Zn-based oxide semiconductor.

6. The semiconductor storage device according to claim 1, further comprising a first gate-selection signal generator circuit electrically connected to a gate of the first transistor, and a second gate-selection signal generator circuit electrically connected to a gate of the second transistor.

7. A semiconductor storage device comprising:

a wiring;

a (2m−

1)-th stage storage circuit (m is a natural number of 1 or more);

a 2m-th stage storage circuit;

a (2m+1)-th stage storage circuit;

a (2m−

1)-th gate-selection signal generator circuit; and

a 2m-th gate-selection signal generator circuit,

wherein the (2m−

1)-th stage storage circuit comprises;

a (2m−

1)-th transistor including a first terminal electrically connected to the wiring;

a (2m−

1)-th data holding portion electrically connected to a second terminal of the (2m−

1)-th transistor, a first terminal of a 2m-th transistor included in the 2m-th stage storage circuit, a first electrode of a (2m−

1)-th capacitor, and an input terminal of a (2m−

1)-th inverter circuit, the (2m−

1)-th data holding portion being configured to hold data supplied from the wiring; and

a (2m−

1)-th NOR circuit configured to receive a signal of an output terminal of the (2m−

1)-th inverter circuit and a first capacitor control signal, the (2m−

1)-th NOR circuit including an output terminal electrically connected to a second electrode of the (2m−

1)-th capacitor,

wherein the 2m-th stage storage circuit comprises;

the 2m-th transistor;

a 2m-th data holding portion electrically connected to a second terminal of the 2m-th transistor, a first terminal of a (2m+1)-th transistor included in a (2m+1)-th stage storage circuit, a first electrode of a 2m-th capacitor, and an input terminal of a 2m-th inverter circuit, the 2m-th data holding portion being configured to hold the data supplied from the (2m−

1)-th data holding portion; and

a 2m-th NOR circuit configured to receive a signal of an output terminal of the 2m-th inverter circuit and a second capacitor control signal, the 2m-th NOR circuit including an output terminal electrically connected to a second electrode of the 2m-th capacitor,

wherein a gate of the (2m−

1)-th transistor is electrically connected to a (2m−

1)-th gate-selection signal generator circuit configured to receive a first gate control signal and a (2m−

1)-th enable signal and to control a conductive state or a non-conductive state of the (2m−

1)-th transistor,

wherein a gate of the 2m-th transistor is electrically connected to a 2m-th gate-selection signal generator circuit configured to receive a second gate control signal and a 2m-th enable signal and to control a conductive state or a non-conductive state of the 2m-th transistor,

wherein the (2m−

1)-th data holding portion is configured to hold the data by turning the (2m−

1)-th transistor and the 2m-th transistor Off,

wherein the 2m-th data holding portion is configured to hold the data by turning the 2m-th transistor and the (2m+1)-th transistor Off,

wherein the (2m−

1)-th NOR circuit is configured to output a first signal depending on the signal of the output terminal of the (2m−

1)-th inverter circuit and the first capacitor control signal to control a potential of the (2m−

1)-th data holding portion by capacitive coupling through the (2m−

1)-th capacitor, and

wherein the 2m-th NOR circuit is configured to output a second signal depending on the signal of the output terminal of the 2m-th inverter circuit and the second capacitor control signal to control a potential of the 2m-th data holding portion by capacitive coupling through the 2m-th capacitor.

8. The semiconductor storage device according to claim 7, wherein at least one of the (2m−

1)-th inverter circuit, the 2m-th inverter circuit, the (2m−

1)-th NOR circuit, the 2m-th NOR circuit, the (2m−

1)-th gate-selection signal generator circuit, and the 2m-th gate-selection signal generator circuit comprises a transistor comprising a semiconductor including silicon.

9. The semiconductor storage device according to claim 8, wherein the transistor and the (2m−

1)-th transistor or the 2m-th transistor are stacked.

10. The semiconductor storage device according to claim 7, wherein the (2m−

1)-th transistor and the 2m-th transistor are each a transistor comprising a semiconductor layer including an oxide semiconductor.

11. The semiconductor storage device according to claim 10, wherein the oxide semiconductor is an In—

Sn—

Zn-based oxide semiconductor.

12. A semiconductor storage device comprising:

a wiring;

a first wiring;

a second wiring;

a first storage circuit comprising a first transistor, a first capacitor, a first data holding portion, a first inverter, a second inverter, and a first NOR circuit;

a second storage circuit comprising a second transistor, a second capacitor, a second data holding portion, a third inverter, a fourth inverter, and a second NOR circuit;

a first selection circuit;

a second selection circuit; and

a third transistor,

wherein the first storage circuit and the second storage circuit are adjacent to each other,

wherein one of a source and a drain of the first transistor is electrically connected to the wiring,

wherein a gate of the first transistor is electrically connected to the first selection circuit,

wherein a gate of the second transistor is electrically connected to the second selection circuit,

wherein the first data holding portion is electrically connected to the other of the source and the drain of the first transistor, a first electrode of the first capacitor, an input terminal of the first inverter, and one of a source and a drain of the second transistor,

wherein an output terminal of the first inverter is electrically connected to a first input terminal of the first NOR circuit and an input terminal of the second inverter,

wherein an output terminal of the first NOR circuit is electrically connected to a second electrode of the first capacitor,

wherein a second input terminal of the first NOR circuit is electrically connected to the first wiring,

wherein the second data holding portion is electrically connected to the other of the source and the drain of the second transistor, a first electrode of the second capacitor, an input terminal of the third inverter, and one of a source and a drain of the third transistor,

wherein an output terminal of the third inverter is electrically connected to a first input terminal of the second NOR circuit and an input terminal of the fourth inverter,

wherein an output terminal of the second NOR circuit is electrically connected to a second electrode of the second capacitor, and

wherein a second input terminal of the second NOR circuit is electrically connected to the second wiring.

13. The semiconductor storage device according to claim 12, wherein at least one of the first to fourth inverters, the first NOR circuit, and the second NOR circuit comprises a transistor comprising a semiconductor including silicon.

14. The semiconductor storage device according to claim 13, wherein the transistor and the first transistor or the second transistor are stacked.

15. The semiconductor storage device according to claim 12, wherein the first to third transistors are each a transistor comprising a semiconductor layer including an oxide semiconductor.

16. The semiconductor storage device according to claim 15, wherein the oxide semiconductor is an In—

Sn—

Zn-based oxide semiconductor.