Semiconductor device and manufacturing method thereof

• US 20070138475A1
• Filed: 02/08/2007
• Published: 06/21/2007
• Est. Priority Date: 04/06/1999
• Status: Active Grant

• Current Assignee: Hidehito Kitakado, Kenji Kasahara, Ritsuko Kawasaki
• Original Assignee: Hidehito Kitakado, Kenji Kasahara, Ritsuko Kawasaki
• Inventors: Kasahara, Kenji, Kitakado, Hidehito, Kawasaki, Ritsuko
• Granted Patent: US 7,638,846 B2
• Time in Patent Office: Days
• US Class Current: 257/66
• CPC Class Codes: G02F 1/13454 Drivers integrated on the active matrix substrate G02F1/136277 takes precedence
• 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 29/42384 for thin film field effect transistors, e.g. characterised by the thickness or the shape of the insulator or the dimensions, the shape or the lay-out of the conductor
• CPC Class Codes: H01L 29/458 for thin film silicon, e.g. source or drain electrode
• CPC Class Codes: H01L 29/4908 for thin film semiconductor, e.g. gate of TFT
• CPC Class Codes: H01L 29/66765 Lateral single gate single channel transistors with inverted structure, i.e. the channel layer is formed after the gate
• CPC Class Codes: H01L 29/78621 with LDD structure or an extension or an offset region or characterised by the doping profile
• CPC Class Codes: H01L 29/78627 with a significant overlap between the lightly doped drain and the gate electrode, e.g. GOLDD
• CPC Class Codes: H01L 29/78633 with a light shield

Abstract

The present invention provides a semiconductor device in which a bottom-gate TFT or an inverted, stagger TFT arranged in each circuit is suitably constructed in conformity with the functionality of the respective circuits, thereby attaining an improvement in the operating efficiency and reliability of the semiconductor device. In the structure, LDD regions in a pixel TFT are arranged so as not to overlap with a channel protection insulating film and to overlap with a gate electrode by at least a portion thereof. LDD regions in an N-channel TFT of a drive circuit is arranged so as not to overlap with a channel protection insulating film and to overlap with a gate electrode by at least a portion thereof. LDD regions in a P-channel TFT of the drive circuit is arranged so as to overlap with a channel protection insulating film and to overlap with the gate electrode.

Claims

1. A semiconductor device comprising:

at least a first n-channel thin film transistor being formed in a display region over a substrate; and

at least a second n-channel thin film transistor and at least a p-channel thin film transistor in a drive circuit each being formed in a periphery of the display region over the substrate;

each of the second n-channel thin film transistor and the p-channel thin film transistor includes;

a gate electrode formed over the substrate,

a first insulating film comprising silicon nitride formed over the gate electrode,

a second insulating film comprising silicon oxide formed over the first insulating film,

a crystalline semiconductor film formed over the second insulating film,

wherein a channel length of the p-channel thin film transistor is shorter than that of the second n-channel thin film transistor,

wherein the first n-channel thin film transistor has at least first and second channel regions, and source and drain regions,

wherein the crystalline semiconductor film of the second n-channel thin film transistor comprises a pair of LDD regions located between a channel region and source and drain regions respectively.

2. A device according to claim 1, further comprising:

an interlayer insulating film formed over the crystalline semiconductor film of the first n-channel thin film transistor,

a wiring formed over the interlayer insulating film, the wiring connected to one of the source region or the drain region,

wherein the wiring overlaps one of the first channel region or second channel region.

3. A device according to claim 1, wherein at least a portion of the LDD region of the first n-channel thin film transistor is formed so as to overlap with the gate electrode of the first n-channel thin film transistor,

wherein at least a portion of the LDD region of the second n-channel thin film transistor is formed so as to overlap with the gate electrode of the second n-channel thin film transistor.

4. A device according to claim 1, further comprising a storage capacitor being connected to the first n-channel thin film transistor,

said storage capacitor including:

a capacitor wiring formed over the substrate;

the first and second insulating films formed over the capacitor wiring; and

a portion of the crystalline semiconductor film formed over the first and second insulating films.

5. A device according to claim 1, wherein the gate electrode comprises at least a material selected from the group consisting of tantalum, titanium, tungsten, molybdenum, and aluminum.

6. A device according to claim 1, wherein the semiconductor device is one selected from the group consisting of a cellular phone, a video camera, a mobile computer, a goggle-type display, a projector, a mobile book, a digital camera, a car navigation device, and a personal computer.

7. A semiconductor device comprising:

at least a first n-channel thin film transistor being formed in a display region over a substrate;

at least a second n-channel thin film transistor and at least a p-channel thin film transistor in a drive circuit each being formed in a periphery of the display region over the substrate; and

a capacitor forming electrode formed adjacent to a portion of a crystalline semiconductor film to form a capacitor therebetween;

the first n-channel thin film transistor includes;

a gate electrode formed over the substrate,

a first insulating film comprising silicon nitride formed over the gate electrode,

a second insulating film comprising silicon oxide formed over the first insulating film,

the crystalline semiconductor film formed over the second insulating film,

wherein the crystalline semiconductor film has first and second channel regions, and source and drain regions, and

wherein a channel length of the p-channel thin film transistor is shorter than that of the second n-channel thin film transistor.

8. A device according to claim 7, wherein the crystalline semiconductor film of the second n-channel thin film transistor comprises a pair of LDD regions located between a channel region and source and drain regions respectively.

9. A device according to claim 7, further comprising:

an interlayer insulating film formed over the crystalline semiconductor film of the first n-channel thin film transistor,

a wiring formed over the interlayer insulating film, the wiring connected to one of the source region or the drain region,

wherein the wiring overlaps one of the first channel region or second channel region.

10. A device according to claim 7, wherein the gate electrode comprises at least a material selected from the group consisting of tantalum, titanium, tungsten, molybdenum, and aluminum.

11. A device according to claim 7, wherein the semiconductor device is one selected from the group consisting of a cellular phone, a video camera, a mobile computer, a goggle-type display, a projector, a mobile book, a digital camera, a car navigation device, and a personal computer.

12. A semiconductor device comprising:

at least a first n-channel thin film transistor being formed in a display region over a substrate; and

at least a second n-channel thin film transistor and at least a p-channel thin film transistor in a drive circuit each being formed in a periphery of the display region over the substrate;

each of the second n-channel thin film transistor and the p-channel thin film transistor includes;

a gate electrode formed over the substrate,

a first insulating film comprising silicon nitride formed over the gate electrode,

a second insulating film comprising silicon oxide formed over the first insulating film,

a crystalline semiconductor film formed over the second insulating film,

wherein a channel length of the p-channel thin film transistor is shorter than that of the second n-channel thin film transistor,

wherein the first n-channel thin film transistor has at least first and second channel regions,

wherein the crystalline semiconductor film of the second n-channel thin film transistor comprises a pair of LDD regions located between a channel region and source and drain regions respectively,

wherein at least a portion of the source and drain regions of the p-channel thin film transistor is formed so as to overlap with the gate electrode of the p-channel thin film transistor,

wherein at least a portion of the LDD region of the second n-channel thin film transistor is formed so as to overlap with the gate electrode of the second n-channel thin film transistor,

wherein source and drain regions of the second n-channel thin film transistor is not formed so as to overlap with the gate electrode of the second n-channel thin film transistor.

13. A device according to claim 12, further comprising:

an interlayer insulating film formed over the crystalline semiconductor film of the first n-channel thin film transistor,

a wiring formed over the interlayer insulating film, the wiring connected to one of the source region or the drain region,

wherein the wiring overlaps one of the first channel region or second channel region.

14. A device according to claim 12, wherein at least a portion of the LDD region of the first n-channel thin film transistor is formed so as to overlap with the gate electrode of the first n-channel thin film transistor,

wherein at least a portion of the LDD region of the second n-channel thin film transistor is formed so as to overlap with the gate electrode of the second n-channel thin film transistor.

15. A device according to claim 12, further comprising a storage capacitor being connected to the first n-channel thin film transistor,

said storage capacitor including:

a capacitor wiring formed over the substrate;

the first and second insulating films formed over the capacitor wiring; and

a portion of the crystalline semiconductor film formed over the first and second insulating films.

16. A device according to claim 12, wherein the gate electrode comprises at least a material selected from the group consisting of tantalum, titanium, tungsten, molybdenum, and aluminum.

17. A device according to claim 12, wherein the semiconductor device is one selected from the group consisting of a cellular phone, a video camera, a mobile computer, a goggle-type display, a projector, a mobile book, a digital camera, a car navigation device, and a personal computer.