Display device and electronic device including the same

• US 8,247,813 B2
• Filed: 12/01/2010
• Issued: 08/21/2012
• Est. Priority Date: 12/04/2009
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Koyama, Jun, Yamazaki, Shunpei
• Primary Examiner(s): Pham, Long
• Application Number:
  US12/957,517
• Publication Number:
  US 20120012847A1
• Time in Patent Office: 629 Days
• Field of Search: 257/43, 257/59, 257/57, 257/52, 257/66, 257/E21.412, 257/E29.068, 257/E21.461
• US Class Current: 257/43
• CPC Class Codes: G02F 1/133345 Insulating layers G02F1/1335, G02F1/1337, G02F1/135, G02F1/136 take precedence
• CPC Class Codes: G02F 1/134309 characterised by their geometrical arrangement
• CPC Class Codes: G02F 1/13452 Conductors connecting driver circuitry and terminals of panels
• CPC Class Codes: G02F 1/13454 Drivers integrated on the active matrix substrate G02F1/136277 takes precedence
• CPC Class Codes: G02F 1/136286 Wiring, e.g. gate line, drain line
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence
• CPC Class Codes: G02F 2201/123 pixel
• CPC Class Codes: G09G 2300/0426 Layout of electrodes and connections
• CPC Class Codes: G09G 2310/0286 Details of a shift registers arranged for use in a driving circuit
• CPC Class Codes: G09G 2310/08 Details of timing specific for flat panels, other than clock recovery
• CPC Class Codes: G09G 2330/023 using energy recovery or conservation
• CPC Class Codes: G09G 3/3266 Details of drivers for scan electrodes
• CPC Class Codes: G09G 3/3275 Details of drivers for data electrodes
• CPC Class Codes: G09G 3/3677 suitable for active matrices only
• CPC Class Codes: G09G 3/3688 suitable for active matrices only
• 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 27/124 with a particular composition, shape or layout of the wiring layers specially adapted to the circuit arrangement, e.g. scanning lines in LCD pixel circuits wiring structures per se H01L23/52
• CPC Class Codes: H01L 27/1285 using control of the annealing or irradiation parameters, e.g. using different scanning direction or intensity for different transistors
• CPC Class Codes: H01L 29/045 by their particular orientation of crystalline planes
• CPC Class Codes: H01L 29/66742 Thin film unipolar transistors
• CPC Class Codes: H01L 29/66969 : of devices having semiconductor bodies not comprising group 14 or group 13/15 materials comprising selenium or tellurium in uncombined form other than as impurities in semiconductor bodies of other materials, comprising cuprous oxide or cuprous iodide H01L21/02365
• CPC Class Codes: H01L 29/7869 : having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate

Abstract

One embodiment of the present invention provides a highly reliably display device in which a high mobility is achieved in an oxide semiconductor. A first oxide component is formed over a base component. Crystal growth proceeds from a surface toward an inside of the first oxide component by a first heat treatment, so that a first oxide crystal component is formed in contact with at least part of the base component. A second oxide component is formed over the first oxide crystal component. Crystal growth is performed by a second heat treatment using the first oxide crystal component as a seed, so that a second oxide crystal component is formed. Thus, a stacked oxide material is formed. A transistor with a high mobility is formed using the stacked oxide material and a driver circuit is formed using the transistor.

Claims

1. A display device comprising:

a substrate;

a pixel over the substrate, the pixel comprising a first transistor and a pixel electrode electrically connected to the first transistor;

a gate driver over the substrate, the gate driver comprising a second transistor and being operationally connected to the first transistor;

an analog switch over the substrate, the analog switch comprising a third transistor and being operationally connected to the pixel;

each of the first transistor, the second transistor, and the third transistor comprising;

a tapered gate electrode including an upper surface and a slanted side surface;

a gate insulating layer over the gate electrode; and

an oxide semiconductor layer comprising indium over the gate electrode with the gate insulating layer interposed therebetween, the oxide semiconductor layer having crystallinity,

wherein the oxide semiconductor layers each include a first portion over the upper surface of the corresponding gate electrode, and a second portion adjacent to the first portion, the second portion being slanted due to the slanted side surface of the corresponding gate electrode;

wherein, for at least one of the first transistor, the second transistor, and the third transistor, c-axis of crystals of the oxide semiconductor layer are substantially perpendicular to a surface of the oxide semiconductor layer in both the first portion and the second portion; and

wherein the at least one of the first transistor, the second transistor, and the third transistor has a field effect mobility of 50 cm²/Vs or higher.

2. The display device according to claim 1, wherein the field effect mobility of each of the transistors is of 100 cm²/Vs or higher.

3. The display device according to claim 1, wherein a diagonal of a display panel is longer than or equal to 20 inches.

4. The display device according to claim 1, wherein a gate electrode of each of the transistors comprises at least one of aluminum, copper, chrome, tantalum, titanium, molybdenum, and tungsten.

15. The display device according to claim 1,

further comprising at least two source line drivers located on two opposite sides of the substrate.

5. A display device comprising:

a substrate;

a pixel over the substrate, the pixel comprising a first transistor and a pixel electrode electrically connected to the first transistor;

a gate driver over the substrate, the gate driver comprising a second transistor and being operationally connected to the first transistor;

a source driver over the substrate, the source driver comprising a third transistor and being operationally connected to the pixel;

each of the first transistor, the second transistor, and the third transistor comprising;

a tapered gate electrode including an upper surface and a slanted side surface;

a gate insulating layer over the gate electrode; and

an oxide semiconductor layer comprising indium over the gate electrode with the gate insulating layer interposed therebetween, the oxide semiconductor layer having crystallinity,

wherein the oxide semiconductor layers each include a first portion over the upper surface of the corresponding gate electrode, and a second portion adjacent to the first portion, the second portion being slanted due to the slanted side surface of the corresponding gate electrode;

wherein, for at least one of the first transistor, the second transistor, and the third transistor, c-axis of crystals of the oxide semiconductor layer are substantially perpendicular to a surface of the oxide semiconductor layer in both the first portion and the second portion; and

wherein the at least one of the first transistor, the second transistor, and the third transistor has a field effect mobility of 50 cm²/Vs or higher.

6. The display device according to claim 5, wherein the field effect mobility of each of the transistors is of 100 cm²/Vs or higher.

7. The display device according to claim 5, wherein a diagonal of a display panel is longer than or equal to 20 inches.

8. The display device according to claim 5, wherein a gate electrode of each of the transistors comprises at least one of aluminum, copper, chrome, tantalum, titanium, molybdenum, and tungsten.

9. The display device according to claim 5, wherein the gate driver and the source driver are formed over the substrate.

16. The display device according to claim 5,

further comprising at least two source line drivers located on two opposite sides of the substrate.

10. A display device comprising:

a substrate;

a pixel over the substrate, the pixel comprising a first transistor and a pixel electrode electrically connected to the first transistor;

a gate driver over the substrate, the gate driver comprising a second transistor and being operationally connected to the first transistor;

a source driver over the substrate, the source driver comprising a third transistor and being operationally connected to the pixel;

each of the first transistor, the second transistor, and the third transistor comprising;

a tapered gate electrode including an upper surface and a slanted side surface;

a gate insulating layer over the gate electrode; and

an oxide semiconductor layer comprising indium over the gate electrode with the gate insulating layer interposed therebetween, the oxide semiconductor layer having crystallinity,

wherein the oxide semiconductor layers each include a first portion over the upper surface of the corresponding gate electrode, and a second portion adjacent to the first portion, the second portion being slanted due to the slanted side surface of the corresponding gate electrode;

wherein, for each of the first transistor, the second transistor, and the third transistor, c-axis of crystals of the oxide semiconductor layer are substantially perpendicular to a surface of the oxide semiconductor layer in both the first portion and the second portion.

11. The display device according to claim 10, wherein the field effect mobility of each of the first to third transistors is of 100 cm²/Vs or higher.

12. The display device according to claim 10, wherein a diagonal of a display panel is longer than or equal to 20 inches.

13. The display device according to claim 10, wherein a gate electrode of each of the first to third transistors comprises at least one of aluminum, copper, chrome, tantalum, titanium, molybdenum, and tungsten.

14. The display device according to claim 10,

wherein the first transistor, the second transistor, and the third transistor have each a field effect mobility of 50 cm²/Vs or higher.

17. The display device according to claim 10,

further comprising at least two source line drivers located on two opposite sides of the substrate.