SEMICONDUCTOR DEVICE

• US 20110110145A1
• Filed: 11/02/2010
• Published: 05/12/2011
• Est. Priority Date: 11/06/2009
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Kato, Kiyoshi, Koyama, Jun, Yamazaki, Shunpei
• Granted Patent: US 8,289,753 B2
• Time in Patent Office: Days
• US Class Current: 365/149
• CPC Class Codes: G11C 11/24 using capacitors G11C11/22 takes precedence; using a combination of semiconductor devices and capacitors G11C11/34, e.g. G11C11/40
• CPC Class Codes: G11C 11/405 with three charge-transfer gates, e.g. MOS transistors, per cell
• CPC Class Codes: G11C 2211/4016 Memory devices with silicon-on-insulator cells
• 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 27/0688 Integrated circuits having a three-dimensional layout
• CPC Class Codes: H01L 27/105 including field-effect components
• CPC Class Codes: H01L 27/1225 with semiconductor materials not belonging to the group IV of the periodic table, e.g. InGaZnO
• CPC Class Codes: H10B 10/125 the MOSFET being a thin film transistor [TFT]
• CPC Class Codes: H10B 41/20 characterised by three-dimensional arrangements, e.g. with cells on different height levels
• CPC Class Codes: H10B 41/70 the floating gate being an electrode shared by two or more components

Abstract

An object is to provide a semiconductor device having a novel structure. A first wiring; a second wiring; a third wiring, a fourth wiring; a first transistor including a first gate electrode, a first source electrode, and a first drain electrode; a second transistor including a second gate electrode, a second source electrode, and a second drain electrode are included. The first transistor is provided over a substrate including a semiconductor material and a second transistor includes an oxide semiconductor layer.

Claims

1. A semiconductor device comprising:

a source line;

a bit line;

a first signal line;

a plurality of second signal lines;

a plurality of word lines;

a plurality of memory cells connected to each other in parallel between the source line and the bit line;

a first driver circuit configured to drive the plurality of second signal lines and the plurality of word lines so that a memory cell specified from the plurality of memory cells by an address signal input to the first driver circuit is selected;

a second driver circuit configured to select and output any of a plurality of writing potentials to the first signal line;

a reading circuit configured to compare a potential of the bit line and a plurality of reference potentials to read data out; and

a potential generating circuit configured to generate and supply the plurality of writing potentials and the plurality of reference potentials to the second driver circuit and the reading circuit,

wherein one of the plurality of memory cells comprises;

a first transistor including a first gate electrode, a first source electrode, and a first drain electrode;

a second transistor including a second gate electrode, a second source electrode, and a second drain electrode; and

a third transistor including a third gate electrode, a third source electrode, and a third drain electrode,

wherein the first transistor is provided on a substrate including a semiconductor material,

wherein the second transistor includes an oxide semiconductor layer,

wherein the first gate electrode and one of the second source electrode and the second drain electrode are electrically connected to each other,

wherein the source line and the first source electrode are electrically connected to each other,

wherein the first drain electrode and the third source electrode are electrically connected to each other,

wherein the bit line and the third drain electrode are electrically connected to each other,

wherein the first signal line and the other of the second source electrode and the second drain electrode are electrically connected to each other,

wherein one of the plurality of second signal lines and the second gate electrode are electrically connected to each other, and

wherein one of the plurality of word lines and the third gate electrode are electrically connected to each other.

2. The semiconductor device according to claim 1, further comprising a capacitor electrically connected to the first gate electrode.

3. The semiconductor device according to claim 1,

wherein the first transistor includes a channel formation region provided on the substrate including the semiconductor material, impurity regions between which the channel formation region is provided, a first gate insulating layer over the channel formation region, the first gate electrode over the first gate insulating layer, and the first source electrode and the first drain electrode,

wherein the first source electrode is electrically connected to one of the impurity regions, and

wherein the second source electrode is electrically connected to the other of the impurity regions.

4. The semiconductor device according to claim 1, wherein the second transistor includes the second gate electrode over the substrate including the semiconductor material, a second gate insulating layer over the second gate electrode, the oxide semiconductor layer over the second gate insulating layer, and the second source electrode and the second drain electrode which are electrically connected to the oxide semiconductor layer.

5. The semiconductor device according to claim 1, wherein the substrate including the semiconductor material is a single crystal semiconductor substrate.

6. The semiconductor device according to claim 1, wherein the semiconductor material is silicon.

7. The semiconductor device according to claim 1, wherein the oxide semiconductor layer includes In, Ga and Zn.

8. The semiconductor device according to claim 1, wherein the oxide semiconductor layer includes a crystal of In₂Ga₂ZnO₇.

9. The semiconductor device according to claim 1, wherein a hydrogen concentration of the oxide semiconductor layer is less than or equal to 5×

10¹⁹ atoms/cm³.

10. The semiconductor device according to claim 1, wherein off current of the second transistor is less than or equal to 1×

10<sup>−

13</sup> A.

11. A semiconductor device comprising:

a source line;

a bit line;

a first signal line;

a plurality of second signal lines;

a plurality of word lines;

a plurality of memory cells connected to each other in parallel between the source line and the bit line;

a first driver circuit configured to drive the plurality of second signal lines and the plurality of word lines so that a memory cell specified from the plurality of memory cells by an address signal input to the first driver circuit is selected;

a second driver circuit configured to select and output any of a plurality of writing potentials to the first signal line;

a reading circuit including a reference memory cell, the reading circuit configured to compare conductance of the specified memory cell and conductance of the reference memory cell to read data out; and

a potential generating circuit configured to generate and supply the plurality of writing potentials and a plurality of reference potentials to the second driver circuit and the reading circuit,

wherein one of the plurality of memory cells comprises;

a first transistor including a first gate electrode, a first source electrode, and a first drain electrode;

a second transistor including a second gate electrode, a second source electrode, and a second drain electrode; and

a third transistor including a third gate electrode, a third source electrode, and a third drain electrode,

wherein the first transistor is provided on a substrate including a semiconductor material,

wherein the second transistor includes an oxide semiconductor layer,

wherein the first gate electrode and one of the second source electrode and the second drain electrode are electrically connected to each other,

wherein the source line and the first source electrode are electrically connected to each other,

wherein the first drain electrode and the third source electrode are electrically connected to each other,

wherein the bit line and the third drain electrode are electrically connected to each other,

wherein the first signal line and the other of the second source electrode and the second drain electrode are electrically connected to each other,

wherein one of the plurality of second signal lines and the second gate electrode are electrically connected to each other, and

wherein one of the plurality of word lines and the third gate electrode are electrically connected to each other.

12. The semiconductor device according to claim 11,

wherein the first transistor includes a channel formation region provided on the substrate including the semiconductor material, impurity regions between which the channel formation region is provided, a first gate insulating layer over the channel formation region, the first gate electrode over the first gate insulating layer, and the first source electrode and the first drain electrode,

wherein the first source electrode is electrically connected to one of the impurity regions, and

wherein the second source electrode is electrically connected to the other of the impurity regions.

13. The semiconductor device according to claim 11, wherein the second transistor includes the second gate electrode over the substrate including the semiconductor material, a second gate insulating layer over the second gate electrode, the oxide semiconductor layer over the second gate insulating layer, and the second source electrode and the second drain electrode which are electrically connected to the oxide semiconductor layer.

14. The semiconductor device according to claim 11, wherein the substrate including the semiconductor material is a single crystal semiconductor substrate.

15. The semiconductor device according to claim 11, wherein the semiconductor material is silicon.

16. The semiconductor device according to claim 11, wherein the oxide semiconductor layer includes In, Ga and Zn.

17. The semiconductor device according to claim 11, wherein the oxide semiconductor layer includes a crystal of In₂Ga₂ZnO₇.

18. The semiconductor device according to claim 11, wherein a hydrogen concentration of the oxide semiconductor layer is less than or equal to 5×

10¹⁹ atoms/cm³.

19. The semiconductor device according to claim 11, wherein off current of the second transistor is less than or equal to 1×

10<sup>−

13</sup> A.

20. A semiconductor device comprising:

a source line;

a bit line;

a first signal line;

a plurality of second signal lines;

a plurality of word lines;

a plurality of memory cells connected to each other in parallel between the source line and the bit line;

a first driver circuit configured to drive the plurality of second signal lines and the plurality of word lines so that a memory cell specified from the plurality of memory cells by an address signal input to the first driver circuit, is selected, and configured to select and output any of a plurality of reference potentials input to the first driver circuit, to one selected from the plurality of word lines;

a second driver circuit configured to select and output any of a plurality of writing potentials to the first signal line;

a reading circuit electrically connected to the bit line and configured to read out data by reading out conductance of the specified memory cell; and

a potential generating circuit configured to generate and supply the plurality of writing potentials and the plurality of reference potentials to the second driver circuit and the reading circuit,

wherein one of the plurality of memory cells comprises;

a first transistor including a first gate electrode, a first source electrode, and a first drain electrode;

a second transistor including a second gate electrode, a second source electrode, and a second drain electrode; and

a capacitor,

wherein the first transistor is provided on a substrate including a semiconductor material,

wherein the second transistor includes an oxide semiconductor layer,

wherein the first gate electrode, one of the second source electrode and the second drain electrode, and one electrode of the capacitor are electrically connected to each other,

wherein the source line and the first source electrode are electrically connected to each other,

wherein the bit line and the first drain electrode are electrically connected to each other,

wherein the first signal line and the other of the second source electrode and the second drain electrode are electrically connected to each other,

wherein one of the plurality of second signal lines and the second gate electrode are electrically connected to each other, and

wherein one of the plurality of word lines and the other electrode of the capacitor are electrically connected to each other.

21. The semiconductor device according to claim 20,

wherein the first transistor includes a channel formation region provided on the substrate including the semiconductor material, impurity regions between which the channel formation region is provided, a first gate insulating layer over the channel formation region, the first gate electrode over the first gate insulating layer, and the first source electrode and the first drain electrode,

wherein the first source electrode is electrically connected to one of the impurity regions, and

wherein the second source electrode is electrically connected to the other of the impurity regions.

22. The semiconductor device according to claim 20, wherein the second transistor includes the second gate electrode over the substrate including the semiconductor material, a second gate insulating layer over the second gate electrode, the oxide semiconductor layer over the second gate insulating layer, and the second source electrode and the second drain electrode which are electrically connected to the oxide semiconductor layer.

23. The semiconductor device according to claim 20, wherein the substrate including the semiconductor material is a single crystal semiconductor substrate.

24. The semiconductor device according to claim 20, wherein the semiconductor material is silicon.

25. The semiconductor device according to claim 20, wherein the oxide semiconductor layer includes In, Ga and Zn.

26. The semiconductor device according to claim 20, wherein the oxide semiconductor layer includes a crystal of In₂Ga₂ZnO₇.

27. The semiconductor device according to claim 20, wherein a hydrogen concentration of the oxide semiconductor layer is less than or equal to 5×

10¹⁹ atoms/cm³.

28. The semiconductor device according to claim 20, wherein off current of the second transistor is less than or equal to 1×

10<sup>−

13</sup> A.