SEMICONDUCTOR DEVICE AND METHOD FOR MANUFACTURING SEMICONDUCTOR DEVICE

• US 20110012112A1
• Filed: 07/14/2010
• Published: 01/20/2011
• Est. Priority Date: 07/18/2009
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: KUWABARA, Hideaki, TAKAHASHI, Tatsuya, MIYAKE, Hiroyuki, YAMAZAKI, Shunpei, SAKATA, Junichiro
• Granted Patent: US 8,552,423 B2
• Time in Patent Office: Days
• US Class Current: 257/57
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence
• CPC Class Codes: H01L 21/02554 Oxides
• CPC Class Codes: H01L 21/02565 Oxide semiconducting materials not being Group 12/16 materials, e.g. ternary compounds
• 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 27/1251 comprising TFTs having a different architecture, e.g. top- and bottom gate TFTs
• 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: H01L 29/78645 with multiple gate

Abstract

An aperture ratio of a semiconductor device is improved. A driver circuit and a pixel are provided over one substrate, and a first thin film transistor in the driver circuit and a second thin film transistor in the pixel each include a gate electrode layer, a gate insulating layer over the gate electrode layer, an oxide semiconductor layer over the gate insulating layer, source and drain electrode layers over the oxide semiconductor layer, and an oxide insulating layer in contact with part of the oxide semiconductor layer over the gate insulating layer, the oxide semiconductor layer, and the source and drain electrode layers. The gate electrode layer, the gate insulating layer, the oxide semiconductor layer, the source and drain electrode layers, and the oxide insulating layer of the second thin film transistor each have a light-transmitting property.

Claims

1. A semiconductor device comprising:

a driver circuit including a first transistor and a pixel including a second transistor over one substrate,

wherein the first transistor and the second transistor each comprise;

a gate electrode layer;

a gate insulating layer over the gate electrode layer;

an oxide semiconductor layer over the gate insulating layer;

a source electrode layer over the oxide semiconductor layer;

a drain electrode layer over the oxide semiconductor layer; and

an oxide insulating layer over the gate insulating layer, the oxide semiconductor layer, the source electrode layer, and the drain electrode layer, the oxide insulating layer being in contact with at least a part of the oxide semiconductor layer between the source electrode layer and the drain electrode layer,

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

wherein the source electrode layer and the drain electrode layer of the first transistor are formed using a material different from that of the source electrode layer and the drain electrode layer of the second transistor and have lower resistance than that of the source electrode layer and the drain electrode layer of the second transistor.

2. The semiconductor device according to claim 1, wherein the source electrode layer and the drain electrode layer of the first transistor comprise a metal film containing an element selected from the group consisting of Al, Cr, Cu, Ta, Ti, Mo, and W.

3. The semiconductor device according to claim 1, wherein the source electrode layer and the drain electrode layer of the second transistor contain at least one selected from the group consisting of indium oxide, an alloy of indium oxide and tin oxide, an alloy of indium oxide and zinc oxide, and zinc oxide.

4. The semiconductor device according to claim 1, further comprising a capacitor portion over the substrate,

wherein the capacitor portion includes a capacitor wiring and a capacitor electrode overlapping with the capacitor wiring, and

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

5. The semiconductor device according to claim 1, further comprising a conductive layer overlapping with the gate electrode layer over the oxide insulating layer of the first transistor.

6. The semiconductor device according to claim 1, further comprising an oxide conductive layer between the oxide semiconductor layer and each of the source and drain electrode layers of the first transistor,

wherein the oxide conductive layer is formed using the same material as that of the source and drain electrode layers of the second transistor.

7. The semiconductor device according to claim 1, wherein a region of the oxide semiconductor layer of the first transistor, which overlaps with the source or drain electrode layer, has lower resistance than that of a channel formation region in the oxide semiconductor layer of the first transistor.

8. The semiconductor device according to claim 1, wherein the oxide semiconductor layer has a depression portion.

9. A method for manufacturing a semiconductor device, the semiconductor device including a driver circuit having a first transistor and a pixel having a second transistor over one substrate, comprising the steps of:

forming a first gate electrode layer and a second gate electrode layer by forming a light-transmitting conductive film over a substrate and selectively etching the light-transmitting conductive film through a first photolithography process, wherein the first gate electrode layer serves as a gate electrode layer of the first transistor and the second gate electrode layer serves as a gate electrode layer of the second transistor;

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

forming a first oxide semiconductor layer and a second oxide semiconductor layer by forming an oxide semiconductor film over the gate insulating layer and selectively etching the oxide semiconductor film through a second photolithography process;

dehydrating or dehydrogenating the first oxide semiconductor layer and the second oxide semiconductor layer;

forming a pair of low-resistance drain regions over the first oxide semiconductor layer, a first source electrode layer and a first drain electrode layer over the pair of low-resistance drain regions respectively, and a second source electrode layer and a second drain electrode layer over the second oxide semiconductor layer by sequentially forming an oxide conductive film and a conductive film over the first and second oxide semiconductor layers which are dehydrated or dehydrogenated and selectively etching the oxide conductive film and the conductive film through a third photolithography process and a fourth photolithography process, wherein the first source electrode layer and the first drain electrode layer serve as a source electrode layer and a drain electrode layer respectively of the first transistor, and the second source electrode layer and the second drain electrode layer serve as a source electrode layer and a drain electrode layer respectively of the second transistor; and

forming an oxide insulating layer in contact with a part of the first oxide semiconductor layer and a part of the second oxide semiconductor layer over the gate insulating layer, the first oxide semiconductor layer, the second oxide semiconductor layer, the first source electrode layer, the first drain electrode layer, the second source electrode layer, and the second drain electrode layer.

10. A method for manufacturing a semiconductor device, the semiconductor device including a driver circuit having a first transistor and a pixel having a second transistor over one substrate, comprising the steps of:

forming a first gate electrode layer and a second gate electrode layer by forming a light-transmitting conductive film over a substrate and selectively etching the light-transmitting conductive film through a first photolithography process, wherein the first gate electrode layer serves as a gate electrode layer of the first transistor and the second gate electrode layer serves as a gate electrode layer of the second transistor;

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

forming an oxide semiconductor film over the gate insulating layer;

dehydrating or dehydrogenating the oxide semiconductor film;

forming a first oxide semiconductor layer and a second oxide semiconductor layer, a pair of low-resistance drain regions over the first oxide semiconductor layer, a first source electrode layer and a first drain electrode layer over the pair of low-resistance drain regions respectively, and a second source electrode layer and a second drain electrode layer over the second oxide semiconductor layer, by sequentially forming an oxide conductive film and a conductive film over the oxide semiconductor film which is dehydrated or dehydrogenated and selectively etching the oxide semiconductor film, the oxide conductive film, and the conductive film through a second photolithography process and a third photolithography process, wherein the first source electrode layer and the first drain electrode layer serve as a source electrode layer and a drain electrode layer respectively of the first transistor, and the second source electrode layer and the second drain electrode layer serve as a source electrode layer and a drain electrode layer respectively of the second transistor, and

forming an oxide insulating layer in contact with a part of the first oxide semiconductor layer and a part of the second oxide semiconductor layer over the gate insulating layer, the first oxide semiconductor layer, the second oxide semiconductor layer, the first source electrode layer, the first drain electrode layer, the second source electrode layer, and the second drain electrode layer.

11. The method for manufacturing a semiconductor device, according to claim 10, wherein the third photolithography process is performed using a multi-tone mask.

12. A method for manufacturing a semiconductor device, the semiconductor device including a driver circuit having a first transistor and a pixel having a second transistor over one substrate, comprising the steps of:

forming a first gate electrode layer and a second gate electrode layer by using a light-transmitting conductive film over a substrate, wherein the first gate electrode layer serves as a gate electrode layer of the first transistor and the second gate electrode layer serves as a gate electrode layer of the second transistor;

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

forming a first oxide semiconductor layer and a second oxide semiconductor layer over the gate insulating layer;

heating at least 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 pair of low-resistance drain regions over the first oxide semiconductor layer, a first source electrode layer and a first drain electrode layer over the pair of low-resistance drain regions respectively, and a second source electrode layer and a second drain electrode layer over the second oxide semiconductor layer, wherein the first source electrode layer and the first drain electrode layer serve as a source electrode layer and a drain electrode layer respectively of the first transistor, and the second source electrode layer and the second drain electrode layer serve as a source electrode layer and a drain electrode layer respectively of the second transistor; and

forming an oxide insulating layer in contact with a part of the first oxide semiconductor layer and a part of the second oxide semiconductor layer over the gate insulating layer, the first oxide semiconductor layer, the second oxide semiconductor layer, the first source electrode layer, the first drain electrode layer, the second source electrode layer, and the second drain electrode layer.

13. A method for manufacturing a semiconductor device, the semiconductor device including a driver circuit having a first transistor and a pixel having a second transistor over one substrate, comprising the steps of:

forming a first gate electrode layer and a second gate electrode layer by using a light-transmitting conductive film over a substrate, wherein the first gate electrode layer serves as a gate electrode layer of the first transistor and the second gate electrode layer serves as a gate electrode layer of the second transistor;

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

forming an oxide semiconductor film over the gate insulating layer;

heating at least the oxide semiconductor film in order to decrease a hydrogen concentration in the oxide semiconductor film;

forming a first oxide semiconductor layer and a second oxide semiconductor layer, a pair of low-resistance drain regions over the first oxide semiconductor layer, a first source electrode layer and a first drain electrode layer over the pair of low-resistance drain regions respectively, and a second source electrode layer and a second drain electrode layer over the second oxide semiconductor layer, wherein the first source electrode layer and the first drain electrode layer serve as a source electrode layer and a drain electrode layer respectively of the first transistor, and the second source electrode layer and the second drain electrode layer serve as a source electrode layer and a drain electrode layer respectively of the second transistor, and

forming an oxide insulating layer in contact with a part of the first oxide semiconductor layer and a part of the second oxide semiconductor layer over the gate insulating layer, the first oxide semiconductor layer, the second oxide semiconductor layer, the first source electrode layer, the first drain electrode layer, the second source electrode layer, and the second drain electrode layer.

14. The method for manufacturing a semiconductor device, according to claim 13, wherein the first oxide semiconductor layer and the second oxide semiconductor layer are formed by using a multi-tone mask.