Capacitor and semiconductor device having oxide semiconductor

• US 9,287,294 B2
• Filed: 12/23/2011
• Issued: 03/15/2016
• Est. Priority Date: 12/28/2010
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei
• Primary Examiner(s): Jung, Michael
• Application Number:
  US13/336,387
• Publication Number:
  US 20120161132A1
• Time in Patent Office: 1,544 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: C04B 2235/3284 Zinc oxides, zincates, cadmium oxides, cadmiates, mercury oxides, mercurates or oxide forming salts thereof
• CPC Class Codes: C04B 2235/3286 Gallium oxides, gallates, indium oxides, indates, thallium oxides, thallates or oxide forming salts thereof, e.g. zinc gallate
• CPC Class Codes: C04B 35/58 based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides containing free binder metal C22C29/00
• 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: H01L 27/1255 integrated with passive devices, e.g. auxiliary capacitors
• CPC Class Codes: H01L 29/78648 arranged on opposing sides of the channel
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

An object is to provide a novel semiconductor device which can store data even when power is not supplied in a data storing time and which does not have a limitation on the number of writing operations. The semiconductor device includes a transistor and a capacitor. The transistor includes a first oxide semiconductor layer, a source electrode and a drain electrode which are in contact with the first oxide semiconductor layer, a gate electrode overlapping with the first oxide semiconductor layer, and a gate insulating layer between the first oxide semiconductor layer and the gate electrode. The capacitor includes the source electrode or the drain electrode, a second oxide semiconductor layer in contact with the source electrode or the drain electrode, and a capacitor electrode in contact with the second oxide semiconductor layer.

Claims

1. A semiconductor device comprising:

an oxide semiconductor layer, the oxide semiconductor layer comprising a first portion and a second portion;

a transistor comprising a gate electrode, a source electrode, a drain electrode, a gate insulating layer, and the first portion of the oxide semiconductor layer; and

a capacitor comprising a first electrode, a second electrode overlapping the first electrode, and the second portion of the oxide semiconductor layer between the first electrode and the second electrode, as a dielectric of the capacitor,

wherein a minimal distance between the first electrode and the second electrode in the capacitor is smaller than a minimal distance between the gate electrode and the source electrode in the transistor by a thickness of the gate insulating layer.

2. The semiconductor device according to claim 1, wherein at least one of the first electrode and the second electrode comprises a metal oxide layer in direct contact with the oxide semiconductor layer.

3. The semiconductor device according to claim 1, wherein the first electrode comprises an In—

Ga—

Zn—

O—

N-based compound conductor.

4. The semiconductor device according to claim 1,

wherein the oxide semiconductor layer comprises an oxide semiconductor or an oxynitride semiconductor, the oxide semiconductor or the oxynitride semiconductor being a non-single-crystal and comprising a triangular or hexagonal atomic arrangement when seen from a direction parallel to a vector normal to an a-b plane and a phase where metal atoms are arranged in a layered manner or the metal atoms and oxygen atoms are arranged in a layered manner in a c-axis direction.

5. The semiconductor device according to claim 1,

wherein the oxide semiconductor layer comprises one or more elements chosen among silicon, germanium, cerium, titanium, tungsten, aluminum, copper, yttrium, lanthanum, vanadium.

6. The semiconductor device according to claim 1,

wherein the first electrode and the second electrode of the capacitor are in direct contact with the second portion of the oxide semiconductor layer.

7. The semiconductor device according to claim 1,

wherein the first portion of the oxide semiconductor layer and the second portion of the oxide semiconductor layer have been formed at a same time from a same oxide semiconductor layer.

8. The semiconductor device according to claim 1,

wherein the outer side edge of the gate insulating layer is covered by the first portion of the oxide semiconductor layer.

9. The semiconductor device according to claim 1,

wherein an extension of the gate insulating layer is not between the first electrode and the second electrode of the capacitor.

10. The semiconductor device according to claim 1,

wherein the second portion of the oxide semiconductor layer is not physically contacting the gate insulating layer.

11. A semiconductor device comprising:

a transistor comprising;

a gate electrode;

a first oxide semiconductor layer overlapping with the gate electrode;

a gate insulating layer interposed between the first oxide semiconductor layer and the gate electrode; and

a source electrode and a drain electrode, each in electrical contact with the first oxide semiconductor layer; and

a capacitor comprising;

a first electrode;

a second electrode electrically connected to one of the source electrode and the drain electrode of the transistor; and

a second oxide semiconductor layer interposed between the first electrode and the second electrode,

wherein a minimal distance between the first electrode and the second electrode in the capacitor is smaller than a minimal distance between the gate electrode and the source electrode in the transistor by a thickness of the gate insulating layer.

12. A semiconductor device according to claim 11,

wherein the gate insulating layer is over the gate electrode;

and

wherein the first oxide semiconductor layer is over the gate insulating layer and the gate electrode.

13. The semiconductor device according to claim 12, further comprising:

an insulating layer over the first oxide semiconductor layer, the source electrode and the drain electrode; and

another gate electrode over the insulating layer and overlapping the first oxide semiconductor layer.

14. The semiconductor device according to claim 11, wherein at least part of the second electrode is formed using a same conductive layer as the source electrode or the drain electrode.

15. The semiconductor device according to claim 11, wherein the second electrode comprises an extension of one of the source electrode and the drain electrode.

16. The semiconductor device according to claim 11,

wherein the first electrode comprises a same first layer as one of the gate electrode and the source electrode, and

wherein the second electrode comprises a same second layer as the other one of the gate electrode and the source electrode.

17. The semiconductor device according to claim 11, wherein at least one of the first electrode and the second electrode comprises a metal oxide layer in direct contact with the second oxide semiconductor layer.

18. The semiconductor device according to claim 11, wherein the first oxide semiconductor layer and the second oxide semiconductor layer are formed during a same process step.

19. The semiconductor device according to claim 11, wherein at least one of the first electrode and the gate electrode comprises an In—

Ga—

Zn—

O—

N-based compound conductor.

20. The semiconductor device according to claim 11,

wherein the first oxide semiconductor layer and the second oxide semiconductor layer each comprise an oxide semiconductor or an oxynitride semiconductor, the oxide semiconductor or the oxynitride semiconductor being a non-single-crystal and comprising a triangular or hexagonal atomic arrangement when seen from a direction parallel to a vector normal to an a-b plane and a phase where metal atoms are arranged in a layered manner or the metal atoms and oxygen atoms are arranged in a layered manner in a c-axis direction.

21. The semiconductor device according to claim 11,

wherein the second oxide semiconductor layer comprises one or more elements chosen among silicon, germanium, cerium, titanium, tungsten, aluminum, copper, yttrium, lanthanum, vanadium.

22. The semiconductor device according to claim 11,

wherein the first electrode and the second electrode of the capacitor are in direct contact with the second oxide semiconductor layer.

23. The semiconductor device according to claim 11,

wherein the first oxide semiconductor layer and the second oxide semiconductor layer have been formed at a same time from a same oxide semiconductor layer.

24. A semiconductor device comprising:

a first conductive layer, the first conductive layer comprising a first portion and a second portion;

a second conductive layer, the second conductive layer comprising a first portion and a second portion;

an oxide semiconductor layer, the oxide semiconductor layer comprising a first portion and a second portion;

a transistor comprising;

the first portion of the first conductive layer as a gate electrode;

a gate insulating layer over the gate electrode;

the first portion of the oxide semiconductor layer over the gate insulating layer and the gate electrode; and

the first portion and the second portion of the second conductive layer as, respectively, a source electrode and a drain electrode, each in electrical contact with the first portion of the oxide semiconductor layer; and

a capacitor comprising;

the second portion of the first conductive layer as a first electrode;

one of the first portion and the second portion of the second conductive layer as a second electrode; and

the second portion of the oxide semiconductor layer between the first electrode and the second electrode,

wherein a minimal distance between the first electrode and the second electrode in the capacitor is smaller than a minimal distance between the gate electrode and the source electrode in the transistor by a thickness of the gate insulating layer.

25. The semiconductor device according to claim 24, wherein at least one of the first electrode and the second electrode comprises a metal oxide layer in direct contact with the second portion of the oxide semiconductor layer.

26. The semiconductor device according to claim 24, wherein the first electrode and the gate electrode comprise an In—

Ga—

Zn—

O—

N-based compound conductor.

27. The semiconductor device according to claim 24,

wherein the oxide semiconductor layer comprises an oxide semiconductor or an oxynitride semiconductor, the oxide semiconductor or the oxynitride semiconductor being a non-single-crystal and comprising a triangular or hexagonal atomic arrangement when seen from a direction parallel to a vector normal to an a-b plane and a phase where metal atoms are arranged in a layered manner or the metal atoms and oxygen atoms are arranged in a layered manner in a c-axis direction.

28. The semiconductor device according to claim 24,

wherein the second portion of the oxide semiconductor layer comprises one or more elements chosen among silicon, germanium, cerium, titanium, tungsten, aluminum, copper, yttrium, lanthanum, vanadium.

29. The semiconductor device according to claim 24,

wherein the first portion of the oxide semiconductor layer and the second portion of the oxide semiconductor layer have been formed at a same time from a same oxide semiconductor layer.