SEMICONDUCTOR DEVICE AND METHOD FOR MANUFACTURING SEMICONDUCTOR DEVICE

• US 20110031492A1
• Filed: 08/02/2010
• Published: 02/10/2011
• Est. Priority Date: 08/07/2009
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: TAKAHASHI, Tatsuya, HOSOBA, Miyuki, YAMAZAKI, Shunpei, SAKATA, Junichiro
• Granted Patent: US 8,629,441 B2
• Time in Patent Office: Days
• US Class Current: 257/43
• CPC Class Codes: H01L 27/1222 with a particular composition, shape or crystalline structure of the active layer
• 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 27/1255 integrated with passive devices, e.g. auxiliary capacitors
• CPC Class Codes: H01L 29/45 Ohmic electrodes
• CPC Class Codes: H10K 59/00 Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
• CPC Class Codes: H10K 59/1213 the pixel elements being TFTs
• CPC Class Codes: H10K 59/123 Connection of the pixel electrodes to the thin film transistors [TFT]

Abstract

The semiconductor device includes a driver circuit including a first thin film transistor and a pixel including a second thin film transistor over one substrate. The first thin film transistor includes a first gate electrode layer, a gate insulating layer, a first oxide semiconductor layer, a first oxide conductive layer, a second oxide conductive layer, an oxide insulating layer which is in contact with part of the first oxide semiconductor layer and which is in contact with peripheries and side surfaces of the first and second oxide conductive layers, a first source electrode layer, and a first drain electrode layer. The second thin film transistor includes a second gate electrode layer, a second oxide semiconductor layer, and a second source electrode layer and a second drain electrode layer each formed using a light-transmitting material.

Claims

1. A semiconductor device comprising:

a driver circuit including a first thin film transistor and a pixel including a second thin film transistor over an insulating surface,

the first thin film transistor comprising;

a first gate electrode layer over the insulating surface;

a gate insulating layer over the first gate electrode layer;

a first oxide semiconductor layer comprising a first channel formation region over the first gate electrode layer with the gate insulating layer therebetween;

a first oxide conductive layer and a second oxide conductive layer over the first oxide semiconductor layer;

an oxide insulating layer which is in contact with the first channel formation region and which is in contact with peripheries and side surfaces of the first oxide conductive layer and the second oxide conductive layer;

a first source electrode layer in contact with the first oxide conductive layer; and

a first drain electrode layer in contact with the second oxide conductive layer; and

the second thin film transistor comprising;

a second gate electrode layer over the insulating surface;

a second oxide semiconductor layer comprising a second channel formation region over the second gate electrode layer with the gate insulating layer therebetween; and

a second source electrode layer and a second drain electrode layer over the second oxide semiconductor layer,

wherein the second gate electrode layer, the second oxide semiconductor layer, the second source electrode layer and the second drain electrode layer each have a light-transmitting property.

2. The semiconductor device according to claim 1, further comprising:

an planarizing insulating layer over the first source electrode layer, the first drain electrode layer, the second source electrode layer and the second drain electrode layer; and

a pixel electrode layer over the planarizing insulating layer,

wherein the pixel electrode layer is in direct contact with the second drain electrode layer through a contact hole of the planarizing insulating layer.

3. The semiconductor device according to claim 1, wherein the first source electrode layer and the first drain electrode layer each comprise a conductive layer of an element selected from Al, Cr, Cu, Ta, Ti, Mo, and W as a main component, or a stack of any of these elements in combination.

4. The semiconductor device according to claim 1, wherein the second source electrode layer and the second drain electrode layer each comprise indium oxide, an indium oxide-tin oxide alloy, an indium oxide-zinc oxide alloy, or zinc oxide.

5. The semiconductor device according to claim 1, further comprising a capacitor portion over the insulating surface,

wherein the capacitor portion includes a capacitor wiring layer and a capacitor electrode layer overlapped with the capacitor wiring layer, and

wherein the capacitor wiring layer and the capacitor electrode layer each have a light-transmitting property.

6. The semiconductor device according to claim 1, further comprising:

an planarizing insulating layer over the first source electrode layer, the first drain electrode layer, the second source electrode layer and the second drain electrode layer; and

a conductive layer over the first channel formation region with the planarizing insulating layer interposed therebetween.

7. The semiconductor device according to claim 1, wherein the first oxide conductive layer and the second oxide conductive layer comprise the same material as that of the second source electrode layer and the second drain electrode layer.

8. The semiconductor device according to claim 1, further comprising a protective layer between the oxide insulating layer and each the first source electrode layer and the first drain electrode layer.

9. The semiconductor device according to claim 1, wherein each the first oxide conductive layer and the second oxide conductive layer cover an end portion of the first oxide semiconductor layer.

10. The semiconductor device according to claim 1,

wherein the first oxide semiconductor layer comprises a first high-resistance source region and a first high-resistance drain region,

wherein the first channel formation region is provided between the first high-resistance source region and the first high-resistance drain region, and

wherein the first high-resistance source region and the first high-resistance drain region each have lower resistance than the first channel formation region.

11. A semiconductor device comprising:

a driver circuit including a first thin film transistor and a pixel including a second thin film transistor over an insulating surface,

the first thin film transistor comprising;

a first gate electrode layer over the insulating surface;

a gate insulating layer over the first gate electrode layer;

a first oxide semiconductor layer comprising a first channel formation region over the first gate electrode layer with the gate insulating layer therebetween;

a first oxide conductive layer and a second oxide conductive layer over the first oxide semiconductor layer;

an oxide insulating layer which is in contact with the first channel formation region and which covers an end portion of the first oxide conductive layer and an end portion of the second oxide conductive layer;

a first source electrode layer over the oxide insulating layer and in contact with the first oxide conductive layer; and

a first drain electrode layer over the oxide insulating layer and in contact with the second oxide conductive layer; and

the second thin film transistor comprising;

a second gate electrode layer over the insulating surface;

a second oxide semiconductor layer comprising a second channel formation region over the second gate electrode layer with the gate insulating layer therebetween; and

a second source electrode layer and a second drain electrode layer over the second oxide semiconductor layer,

wherein the second gate electrode layer, the second oxide semiconductor layer, the second source electrode layer and the second drain electrode layer each have a light-transmitting property.

12. The semiconductor device according to claim 11, further comprising:

an planarizing insulating layer over the first source electrode layer, the first drain electrode layer, the second source electrode layer and the second drain electrode layer; and

a pixel electrode layer over the planarizing insulating layer,

wherein the pixel electrode layer is in direct contact with the second drain electrode layer through a contact hole of the planarizing insulating layer.

13. The semiconductor device according to claim 11, wherein the first source electrode layer and the first drain electrode layer each comprise a conductive layer of an element selected from Al, Cr, Cu, Ta, Ti, Mo, and W as a main component, or a stack of any of these elements in combination.

14. The semiconductor device according to claim 11, wherein the second source electrode layer and the second drain electrode layer each comprise indium oxide, an indium oxide-tin oxide alloy, an indium oxide-zinc oxide alloy, or zinc oxide.

15. The semiconductor device according to claim 11, further comprising a capacitor portion over the insulating surface,

wherein the capacitor portion includes a capacitor wiring layer and a capacitor electrode layer overlapped with the capacitor wiring layer, and

wherein the capacitor wiring layer and the capacitor electrode layer each have a light-transmitting property.

16. The semiconductor device according to claim 11, further comprising:

an planarizing insulating layer over the first source electrode layer, the first drain electrode layer, the second source electrode layer and the second drain electrode layer; and

a conductive layer over the first channel formation region with the planarizing insulating layer interposed therebetween.

17. The semiconductor device according to claim 11, wherein the first oxide conductive layer and the second oxide conductive layer comprise the same material as that of the second source electrode layer and the second drain electrode layer.

18. The semiconductor device according to claim 11, further comprising a protective layer between the oxide insulating layer and each the first source electrode layer and the first drain electrode layer.

19. The semiconductor device according to claim 11, wherein each the first oxide conductive layer and the second oxide conductive layer cover an end portion of the first oxide semiconductor layer.

20. The semiconductor device according to claim 11,

wherein the first oxide semiconductor layer comprises a first high-resistance source region and a first high-resistance drain region,

wherein the first channel formation region is provided between the first high-resistance source region and the first high-resistance drain region, and

wherein the first high-resistance source region and the first high-resistance drain region each have lower resistance than the first channel formation region.

21. A method for manufacturing a semiconductor device, comprising the steps of:

forming a first gate electrode layer and a second gate electrode layer over an insulating surface;

forming a gate insulating layer over the first gate electrode layer and the second gate electrode layer;

forming a first oxide semiconductor layer over the first gate electrode layer with the gate insulating layer interposed therebetween and forming a second oxide semiconductor layer over the second gate electrode layer with the gate insulating layer interposed therebetween;

performing heat treatment on the first oxide semiconductor layer and the second oxide semiconductor layer in order to decrease a hydrogen concentration in the first oxide semiconductor layer and the second oxide semiconductor layer;

forming a first oxide conductive layer and a second oxide conductive layer over the first oxide semiconductor layer, and forming a second source electrode layer and a second drain electrode layer over the second oxide semiconductor layer after performing the heat treatment;

forming an oxide insulating layer over the first oxide conductive layer and the second oxide conductive layer so that the oxide insulating layer is in contact with part of the first oxide semiconductor layer between the first oxide conductive layer and the second oxide conductive layer, and part of the first oxide conductive layer and part of the second oxide conductive layer are exposed; and

forming a first source electrode layer over the first oxide conductive layer, and a first drain electrode layer over the second oxide conductive layer.

22. The method for manufacturing a semiconductor device according to claim 21, wherein a resist mask is formed using a multi-tone mask, so that the first oxide semiconductor layer, the second oxide semiconductor layer, the first oxide conductive layer, the second oxide conductive layer, the second source electrode layer, and the second drain electrode layer are formed by etching using the resist mask.