Semiconductor device

• US 6,878,968 B1
• Filed: 05/09/2000
• Issued: 04/12/2005
• Est. Priority Date: 05/10/1999
• Status: Expired due to Term

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Ohnuma, Hideto
• Primary Examiner(s): Flynn, Nathan J.
• Assistant Examiner(s): MONDT, JOHANNES P
• Application Number:
  US09/566,985
• Time in Patent Office: 1,799 Days
• Field of Search: 257/66, 257/69, 257/70, 257/72, 257/75, 257/913, 257/59, 438/310, 438/402, 438/471, 438/149, 438/151, 438/157, 438/166
• US Class Current: 257/75
• CPC Class Codes: H01L 27/12 the substrate being other than a semiconductor body, e.g. an insulating body
• CPC Class Codes: H01L 27/1277 using a crystallisation promoting species, e.g. local introduction of Ni catalyst
• CPC Class Codes: H01L 29/66757 Lateral single gate single channel transistors with non-inverted structure, i.e. the channel layer is formed before the gate
• CPC Class Codes: H01L 29/78675 with normal-type structure, e.g. with top gate
• CPC Class Codes: H01L 29/78684 having a semiconductor body comprising semiconductor materials of Group IV not being silicon, or alloys including an element of the group IV, e.g. Ge, SiN alloys, SiC alloys H01L29/7869 takes precedence

Abstract

A metallic element is effectively removed from a semiconductor film crystallized by using the metallic element. The concentration distribution of phosphorous or antimony in the depth direction of at least one of a source and a drain of a TFT semiconductor film has: a region in which the concentration is 1×10²⁰ atoms/cm³ or less is 5 nm or greater in thickness, and 5×10¹⁹ atoms/cm³ or greater in the maximum value. By creating this concentration distribution, and by thermal annealing at about between 500 and 650° C., the metallic element within a channel forming region diffuses to the source or the drain, and at the same time as gettering is accomplished, the region in which the concentration is 1×10²⁰ atoms/cm³ or less is made into a nucleus and the source region/drain region is recrystallized.

Claims

1. A semiconductor device comprising a semiconductor film on an insulating surface, the semiconductor film having an n-type impurity region containing a periodic table group 15 element, a channel forming region, and a gate electrode over the channel forming region,

wherein the n-type impurity region contains a metallic element for promoting crystallization of silicon,

wherein the concentration distribution of the group 15 element of the n-type impurity region in the depth direction has a region in which the concentration is 1×

10²⁰ atoms/cm³ or less, with a thickness of 5 nm or greater and 20 nm or less, and the maximum concentration of 5×

10¹⁹ atoms/cm³ or greater is located in the semiconductor film, and

wherein a concentration of the group 15 element in the region monotonically decreases toward the insulating surface.

2. The semiconductor device according to claim 1, wherein the concentration of the metallic element is lower in the channel forming region than in the n-type impurity region.

5. The semiconductor device according to any one of claims 1 to 3, wherein the group 15 element is phosphorus or antimony.

6. The semiconductor device according to any one of claims 1 to 3, wherein the group 13 element is boron.

7. The semiconductor device according to any one of claims 1 to 3, wherein the metallic element is one element or plural kinds of elements selected from the group consisting of Ni, Fe, Co, Ru, Rh, Pd, Os, Ir, Pt, Cu, and Au.

8. The semiconductor device according to claim 1 or 3 wherein said semiconductor device is an active matrix liquid crystal display device.

9. The semiconductor device according to claim 1 or 3 wherein said semiconductor device is an active matrix electro-luminescence display device.

10. The semiconductor device according to claim 1 or 3 wherein said semiconductor device is selected from the group consisting of personal computer, a video camera, a mobile computer, a goggle type display, a DVD player, a digital camera, and a projector.

29. The semiconductor device according to claim 1, wherein the maximum concentration is in the range of 1×

10²⁰ atoms/cm³ to 1×

10²² atoms/cm³.

3. A semiconductor device comprising a semiconductor film an insulating surface, the semiconductor film having a p-type impurity region containing a periodic table group 15 element and a periodic table group 13 element and a channel forming region,

wherein the p-type impurity region contains a metallic element for promoting crystallization of silicon,

wherein the concentration distribution of the group 15 element of the p-type impurity region in the depth direction has a region in which the concentration is 1×

10²⁰ atoms/cm³ or less with a thickness 5 nm or greater and 20 nm or less, and the maximum concentration of 5×

10¹⁹ atoms/cm³ or greater is located in the semi conductor film, and

wherein a concentration of the group 15 element in the region monotonically decreases toward the insulating surface.

4. The semiconductor device according to claim 3, wherein the concentration of the metallic element is lower in the channel forming region than in the p-type impurity region.

30. The semiconductor device according to claim 3, wherein the maximum concentration is in the range of 1×

10²⁰ atoms/cm³ to 1×

10²² atoms/cm³.

11. A semiconductor device comprising:

a semiconductor film comprising crystalline silicon formed on an insulating surface;

a channel region formed in said semiconductor film;

at least two n-type impurity regions formed in said semiconductor film with said channel region interposed therebetween, said n-type impurity regions containing a metal element for promoting crystallization of silicon and an impurity selected from group 15 element;

wherein a concentration of said impurity in said n-type impurity regions monotonically decreases toward said insulating surface in a first portion of said semiconductor layer, said first portion containing said impurity at a concentration not higher than 1×

10²⁰ atoms/cm³, and a thickness of said first portion is at least 5 nm and 20 nm or less, and

wherein a concentration of said n-type impurity regions in a second portion of said semiconductor layer is higher than the concentration of said n-type impurity regions in the first portion.

12. The semiconductor device according to claim 11 wherein said metal element is selected from the group consisting of Ni, Fe, Co, Rh, Pd, Os, Ir, Pt, Cu, and Au.

13. The semiconductor device according to claim 11 wherein said impurity is selected from the group consisting of phosphorus and antimony.

14. The semiconductor device according to claim 11 wherein said semiconductor device is an active matrix liquid crystal display device.

15. The semiconductor device according to claim 11 wherein said semiconductor device is an active matrix electro-luminescence display device.

16. The semiconductor device according to claim 11 wherein said semiconductor device is selected from the group consisting of personal computer, a video camera, a mobile computer, a goggle type display, a DVD player, a digital camera, and a projector.

17. A semiconductor device comprising:

a semiconductor film comprising crystalline silicon formed on an insulating surface;

a channel region formed in said semiconductor film;

at least a pair of n-type impurity regions formed in said semiconductor film with said channel region interposed therebetween, said n-type impurity regions containing a metal element for promoting crystallization of silicon and an impurity element selected from group 15 element and

a first portion and a second portion formed in said n-type impurity region, said first portion being closer to said insulating surface than said second portion,

wherein a concentration of said impurity element in said first portion is not higher than 1×

10²⁰ atoms/cm³, and a thickness of said first portion is a least 5 nm and 20 nm or less,

wherein a concentration of said impurity element in said second portion is higher than the concentration of said impurity element in said first portion, and

wherein a concentration of the group 15 element in the first region monotonically decreases toward the insulating surface.

18. The semiconductor device according to claim 17, wherein said semiconductor device is an active matrix liquid crystal display device.

19. The semiconductor device according to claim 17, wherein said semiconductor device is an active matrix electro-luminescence display device.

20. The semiconductor device according to claim 17, wherein said semiconductor device is selected from the group consisting of personal computer, a video camera, a mobile computer, a goggle type display, a digital camera, and a projector.

21. A semiconductor device having a thin film transistor, said thin film transistor comprising:

a semiconductor film comprising crystalline silicon formed on an insulating surface;

a channel region formed in said semiconductor film;

at least a pair of n-type impurity regions formed in said semiconductor film with said channel region interposed therebetween, said n-type impurity regions containing a metal element for promoting crystallization of silicon and an impurity element selected from group 15 element; and

a first portion and a second portion formed in said n-type impurity region, said first portion being closer to said insulating surface than said second portion,

wherein a concentration of said impurity element in said first portion is not higher than 1×

10²⁰ atoms/cm³, and a thickness of said first portion is at least 5 nm and 20 nm or less,

wherein a concentration of said impurity element in said second portion is higher than the concentration of said impurity element in the first portion, and

wherein a concentration of the group 15 element in the first region monotonically decreases toward the insulating surface.

22. The semiconductor device according to claim 21, wherein said semiconductor device is an active matrix liquid crystal display device.

23. The semiconductor device according to claim 21, wherein said semiconductor device is an active matrix electro-luminescence display device.

24. The semiconductor device according to claim 21, wherein said semiconductor device is selected from the group consisting of personal computer, a video camera, a mobile computer, a goggle type display, a digital camera and a projector.

25. A semiconductor device comprising:

a semiconductor film comprising crystalline silicon formed on an insulating surface;

a channel region formed in said semiconductor film;

at least a pair of impurity regions formed in said semiconductor film with said channel region interposed therebetween, said impurity regions containing a metal element for promoting crystallization of silicon and an impurity element selected from group 15 element; and

a first portion and a second portion formed in said impurity region, said first portion being closer to said insulating surface than said second portion,

wherein a concentration of said impurity element in said first portion is not higher than 1×

10 ²⁰ atoms/cm³, and a thickness of said first portion is at least 5 nm and 20 nm or less,

wherein a concentration of said impurity element in said second portion is higher than the concentration of said impurity element in the first portion,

wherein a concentration of the group 15 element in the first region monotonically decreases toward the insulating surface.

26. The semiconductor device according to claim 25, wherein said semiconductor device is an active matrix liquid crystal display device.

27. The semiconductor device according to claim 25, wherein said semiconductor device is an active matrix electro-luminescence display device.

28. The semiconductor device according to claim 25, wherein said semiconductor device is selected from the group consisting of personal computer, a video camera, a mobile computer, a goggle type display, a digital camera, and a projector.

31. A semiconductor device comprising a semiconductor film on an insulating surface, the semiconductor film having an n-type impurity region containing a periodic table group 15 element, a channel forming region, and a gate electrode over the channel forming region,

wherein the n-type impurity region contains a metallic element for promoting crystallization of silicon,

wherein the concentration distribution of the group 15 element of the n-type impurity region in the depth direction has a region in which the concentration is 1×

10²⁰ atoms/cm³ or less with a thickness of 5 nm or greater and 20 nm or less, and the maximum concentration of 5×

10¹⁹ atoms/cm³ or greater is located in the semiconductor film.

32. The semiconductor device according to claim 31, wherein the region in which the concentration is 1×

10²⁰ atoms/cm³ or less with the thickness of 5 nm or greater and 20 nm or less is in contact with the insulating surface.