Semiconductor device and method of fabricating the same

• US 6,639,244 B1
• Filed: 01/10/2000
• Issued: 10/28/2003
• Est. Priority Date: 01/11/1999
• Status: Expired due to Term

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Shibata, Hiroshi, Fukunaga, Takeshi, Koyama, Jun, Yamazaki, Shunpei
• Primary Examiner(s): Jackson, Jerome
• Application Number:
  US09/479,842
• Time in Patent Office: 1,387 Days
• Field of Search: 257/72, 257/70
• US Class Current: 257/72
• CPC Class Codes: G02F 1/13454 Drivers integrated on the active matrix substrate G02F1/136277 takes precedence
• CPC Class Codes: G02F 1/136213 Storage capacitors associated with the pixel electrode
• CPC Class Codes: H01L 27/1214 comprising a plurality of TFTs formed on a non-semiconducting substrate, e.g. driving circuits for AMLCDs
• CPC Class Codes: H01L 27/1255 integrated with passive devices, e.g. auxiliary capacitors
• CPC Class Codes: H01L 27/1277 using a crystallisation promoting species, e.g. local introduction of Ni catalyst

Abstract

A semiconductor device having high TFT characteristics is realized. In a pixel matrix circuit of an AM-LCD, a lower electrode of a storage capacitor is made to include an element in group 15 and a catalytic element used for crystallization, so that its resistance is reduced. Further, a dielectric of the storage capacitor is made thin, so that capacity can be secured without increasing an area for formation of the capacitance. Thus, it becomes possible to secure sufficient storage capacitor even in the AM-LCD having a size of 1 inch or less in diagonal without lowering an opening ratio.

Claims

1. A semiconductor device comprising a pixel thin film transistor and a driver circuit for driving said pixel thin film transistor both formed over a same substrate, said semiconductor device comprising:

a semiconductor layer over said substrate, said semiconductor layer having at least a pair of impurity regions, a channel formation region between said pair of impurity regions, and a capacitor formation portion, wherein said capacitor formation portion contains a catalytic element for promoting a crystallization of said semiconductor layer at a concentration of 1×

10¹⁹ atoms/cm³ or more;

a first insulating film adjacent to said channel formation region;

a second insulating film adjacent to said capacitor formation portion of said semiconductor layer, wherein said second insulating film is thinner than said first insulating film;

a gate electrode adjacent to said channel formation region with said first insulating film interposed therebetween;

an upper capacitor electrode to form a storage capacitor adjacent to said capacitor formation portion of said semiconductor layer with said second insulating film interposed therebetween;

a third insulating film over said storage capacitor and said gate electrode;

an electrode on said third insulating film;

a fourth insulating film over said third insulating film and said electrode;

a black mask on said fourth insulating film;

a fifth insulating film over said fourth insulating film and said black mask; and

a pixel electrode on said fifth insulating film, wherein said pixel electrode is electrically connected to one of said pair of impurity regions.

7. A semiconductor device according to any one of claims 1-6, wherein said first insulating film and said second insulating film comprise silicon oxide.

8. A semiconductor device according to any one of claims 1-6, wherein said first insulating film has a thickness between 50 and 200 nm.

9. A semiconductor device according to any one of claims 1-6, wherein said gate electrode comprises one selected from the group consisting of doped silicon, tungsten, tantalum, molybdenum, and titanium.

10. A semiconductor device according to any one of claims 1-6, wherein said semiconductor device is a liquid crystal display device.

11. A semiconductor device according to any one of claims 1-6, wherein said semiconductor device is an electro-luminescence display device.

12. A semiconductor device according to any one of claims 1-6, wherein said semiconductor device is one selected from the group consisting of a personal computer, video camera, a mobile computer, a goggle-type display, a DVD player, a digital camera, a portable telephone, and a portable electronic book.

13. A semiconductor device according to any one of claims 1-6, wherein said semiconductor device is a front type projector.

14. A semiconductor device according to any one of claims 1-6, wherein said semiconductor device is a rear type projector.

15. A semiconductor device according to any one of claims 1, 2, 4, and 5, wherein said fourth and fifth insulating films comprise one selected from the group consisting of polyamide, acrylic, polyamide, and BCB.

16. A semiconductor device according to any one of claims 1, 2, 4, and 5, wherein said black mask comprises titanium.

29. A semiconductor device according to any one of claims 1-6, and 20 wherein said catalytic element comprises at least one selected from the group consisting of nickel, cobalt, palladium, germanium, platinum, iron, and copper.

30. A semiconductor device according to any one of claims 1-6, and 20 wherein said channel formation region contains said catalytic element at a concentration of 2×

10¹⁷ atoms/cm³ or less.

2. A semiconductor device comprising a pixel thin film transistor and a driver circuit for driving said pixel thin film transistor both formed over a same substrate, said semiconductor device comprising:

a semiconductor layer over said substrate, said semiconductor layer having at least a pair of impurity regions, a channel formation region between said pair of impurity regions, and a capacitor formation portion, wherein said capacitor formation portion contains a catalytic element for promoting a crystallization of said semiconductor layer at a concentration of 1×

10¹⁹ atoms/cm³ or more;

a first insulating film adjacent to said channel formation region;

a second insulating film adjacent to said capacitor formation portion of said semiconductor layer, wherein said second insulating film is thinner than said first insulating film;

a gate electrode adjacent to said channel formation region with said first insulating film interposed therebetween;

an upper capacitor electrode of a same material as said gate electrode to form a storage capacitor adjacent to said capacitor formation portion of said semiconductor layer with said second insulating film interposed therebetween;

a third insulating film over said storage capacitor and said gate electrode;

an electrode on said third insulating film;

a fourth insulating film over said third insulating film and said electrode;

a black mask on said fourth insulating film;

a fifth insulating film over said fourth insulating film and said black mask; and

a pixel electrode on said fifth insulating film, wherein said pixel electrode is electrically connected to one of said pair of impurity regions.

3. A semiconductor device comprising:

a pixel thin film transistor and a driver circuit for driving said pixel thin film transistor both formed over a same substrate, said pixel thin film transistor comprising;

a semiconductor layer over said substrate, said semiconductor layer having at least a pair of impurity regions, a channel formation region between said pair of impurity regions, and a capacitor formation portion, wherein said capacitor formation portion contains a catalytic element for promoting a crystallization of said semiconductor layer at a concentration of 1×

10¹⁹ atoms/cm³ or more; and

a gate electrode adjacent to said channel formation region with a first insulating film interposed there between,

a storage capacitor electrically connected to said pixel thin film transistor, said storage capacitor comprising;

said capacitor formation portion of said semiconductor layer; and

an upper capacitor electrode adjacent to said capacitor formation portion with a second insulating film interposed therebetween, wherein said second insulating film is a thermal oxidation film of said semiconductor layer having a thickness between 10 and 30 nm, and wherein said second insulating film is thinner than said first insulating film.

4. A semiconductor device comprising a pixel thin film transistor and a driver circuit for driving said pixel thin film transistor both formed over a same substrate, said semiconductor device comprising:

a semiconductor layer over said substrate, said semiconductor layer having at least a pair of impurity regions, a channel formation region between said pair of impurity regions, and a capacitor formation portion, wherein said capacitor formation portion contains a catalytic element for promoting a crystallization of said semiconductor layer at a concentration of 1×

10¹⁹ atoms/cm³ or more;

a first insulating film adjacent to said channel formation region;

a second insulating film adjacent to said capacitor formation portion of said semiconductor layer, wherein said second insulating film is a thermal oxidation film of said semiconductor layer, and is thinner than said first insulating film;

a gate electrode adjacent to said channel formation region with said first insulating film interposed therebetween;

an upper capacitor electrode to form a storage capacitor adjacent to said capacitor formation portion of said semiconductor layer with said second insulating film interposed therebetween;

a third insulating film over said storage capacitor and said gate electrode;

an electrode on said third insulating film;

a fourth insulating film over said third insulating film and said electrode;

a black mask on said fourth insulating film;

a fifth insulating film over said fourth insulating film and said black mask; and

a pixel electrode on said fifth insulating film, wherein said pixel electrode is electrically connected to one of said pair of impurity regions.

5. A semiconductor device comprising a pixel thin film transistor and a driver circuit for driving said pixel thin film transistor both formed over a same substrate, said semiconductor device comprising:

a semiconductor layer over said substrate, said semiconductor layer having at least a pair of impurity regions, a channel formation region between said pair of impurity regions, and a capacitor formation portion, wherein said capacitor formation portion contains a group 15 element and a catalytic element for promoting a crystallization of said semiconductor layer at a concentration of 1×

10¹⁹ atoms/cm³ or more;

a first insulating film adjacent to said channel formation region;

a second insulating film adjacent to said capacitor formation portion of said semiconductor layer, wherein said second insulating film is thinner than said first insulating film;

a gate electrode adjacent to said channel formation region with said first insulating film interposed therebetween;

an upper capacitor electrode to form a storage capacitor adjacent to said capacitor formation portion of said semiconductor layer with said second insulating film interposed therebetween;

a third insulating film over said storage capacitor and said gate electrode;

an electrode on said third insulating film;

a fourth insulating film over said third insulating film and said electrode;

a black mask on said fourth insulating film;

a fifth insulating film over said fourth insulating film and said black mask; and

a pixel electrode on said fifth insulating film, wherein said pixel electrode is electrically connected to one of said pair of impurity regions.

17. A semiconductor device according to claim 5 wherein a concentration of said group 15 element is between 5×

10¹⁸ and 1×

10²⁰ atoms/cm³.

6. A semiconductor device comprising a pixel thin film transistor and a driver circuit for driving said pixel thin film transistor both formed over a same substrate, said semiconductor device comprising:

a semiconductor layer over said substrate, said semiconductor layer having at least a pair of impurity regions, a channel formation region between said pair of impurity regions, and a capacitor formation portion, wherein said capacitor formation portion contains a catalytic element for promoting a crystallization of said semiconductor layer at a concentration of 1×

10¹⁹ atoms/cm³ or more;

a first insulating film adjacent to said channel formation region;

a second insulating film adjacent to said capacitor formation portion of said semiconductor layer, wherein said second insulating film is thinner than said first insulating film;

a gate electrode adjacent to said channel formation region with said first insulating film interposed therebetween;

an upper capacitor electrode comprising a semiconductor material to form a storage capacitor adjacent to said capacitor formation portion of said semiconductor layer with said second insulating film interposed therebetween;

a third insulating film over said storage capacitor and said gate electrode;

an electrode on said third insulating film;

a fourth insulating film over said third insulating film and said electrode;

a black mask on said fourth insulating film;

a fifth insulating film over said fourth insulating film and said black mask; and

a pixel electrode on said fifth insulating film, wherein said pixel electrode is electrically connected to one of said pair of impurity regions.

18. A semiconductor device according to claim 6, wherein said fourth and fifth insulating films comprise one selected from the group consisting of polyimide, acrylic, polyamide, and BCB.

19. A semiconductor device according to claim 6, wherein said black mask comprises titanium.

20. A semiconductor device comprising:

a pixel thin film transistor and a driver circuit for driving said pixel thin film transistor both formed over a same substrate, said pixel thin film transistor comprising;

a semiconductor layer over said substrate, said semiconductor layer having at least a pair of impurity regions, a channel formation region between said pair of impurity regions, and a capacitor formation portion, wherein said capacitor formation portion contains a catalytic element for promoting a crystallization of said semiconductor layer at a concentration of 1×

10¹⁹ atoms/cm³ or more; and

a gate electrode adjacent to said channel formation region with a first insulating film interposed there between,

a storage capacitor electrically connected to said pixel thin film transistor, said storage capacitor comprising;

said capacitor formation portion of said semiconductor layer; and

an upper capacitor electrode adjacent to said capacitor formation portion with a second insulating film interposed therebetween, wherein said second insulating film is thinner than said first insulating film.

21. A semiconductor device according to claim 20 wherein said first insulating film and said second insulating film comprise silicon oxide.

22. A semiconductor device according to claim 20 wherein said first insulating film has a thickness between 50 and 200 nm.

23. A semiconductor device according to claim 20 wherein said gate electrode comprises one selected from the group consisting of doped silicon, tungsten, tantalum, molybdenum, and titanium.

24. A semiconductor device according to claim 20 wherein said semiconductor device is a liquid crystal display device.

25. A semiconductor device according to claim 20 wherein said semiconductor device is an electro-luminescence display device.

26. A semiconductor device according to claim 20 wherein said semiconductor device is one selected from the group consisting of a personal computer, a video camera, a mobile computer, a goggle-type display, a DVD player, a digital camera, a portable telephone, and a portable electronic book.

27. A semiconductor device according to claim 20 wherein said semiconductor device is a front type projector.

28. A semiconductor device according to claim 20 wherein said semiconductor device is a rear type projector.