Semiconductor device and manufacturing method thereof

• US 9,882,062 B2
• Filed: 10/26/2015
• Issued: 01/30/2018
• Est. Priority Date: 01/12/2011
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei
• Primary Examiner(s): Rodela, Eduardo A
• Application Number:
  US14/922,862
• Publication Number:
  US 20160049519A1
• Time in Patent Office: 827 Days
• 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 27/1225 with semiconductor materials not belonging to the group IV of the periodic table, e.g. InGaZnO
• CPC Class Codes: H01L 27/1237 with a different composition, shape, layout or thickness of the gate insulator in different devices
• 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 27/1248 with a particular composition or shape of the interlayer dielectric specially adapted to the circuit arrangement
• CPC Class Codes: H01L 27/1251 comprising TFTs having a different architecture, e.g. top- and bottom gate TFTs
• CPC Class Codes: H01L 29/045 by their particular orientation of crystalline planes
• CPC Class Codes: H01L 29/0847 of field-effect transistors with insulated gate H01L29/0653 takes precedence; with a passive supplementary region between source or drain and substrate related to punch-through, capacity or isolation phenomena H01L29/1079; with LDD or DDD structure H01L29/7833; for thin film transistors H01L29/78618
• CPC Class Codes: H01L 29/1033 with insulated gate, e.g. characterised by the length, the width, the geometric contour or the doping structure with channel and gate aligned in the lengthwise direction H01L29/42376; with buried channel H01L29/7838
• CPC Class Codes: H01L 29/24 including, apart from doping materials or other impurities, only semiconductor materials not provided for in groups H01L29/16, H01L29/18, H01L29/20, H01L29/22 including organic materials H10K99/00
• 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 29/66969 of devices having semiconductor bodies not comprising group 14 or group 13/15 materials comprising selenium or tellurium in uncombined form other than as impurities in semiconductor bodies of other materials, comprising cuprous oxide or cuprous iodide H01L21/02365
• CPC Class Codes: H01L 29/78609 for preventing leakage current H01L29/78618 takes precedence
• CPC Class Codes: H01L 29/78687 with a multilayer structure or superlattice structure
• CPC Class Codes: H01L 29/7869 having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate
• CPC Class Codes: H01L 29/78693 the semiconducting oxide being amorphous
• CPC Class Codes: H01L 29/78696 characterised by the structure of the channel, e.g. multichannel, transverse or longitudinal shape, length or width, doping structure, or the overlap or alignment between the channel and the gate, the source or the drain, or the contacting structure of the channel H01L29/78612 takes precedence; transistors having a drain offset region or a lightly doped drain [LDD] H01L29/78621
• CPC Class Codes: H10K 59/1213 the pixel elements being TFTs
• CPC Class Codes: H10K 59/1216 the pixel elements being capacitors

Abstract

A first oxide insulating film is formed over a substrate. After a first oxide semiconductor film is formed over the first oxide insulating film, heat treatment is performed, so that hydrogen contained in the first oxide semiconductor film is released and part of oxygen contained in the first oxide insulating film is diffused into the first oxide semiconductor film. Thus, a second oxide semiconductor film with reduced hydrogen concentration and reduced oxygen defect is formed. Then, the second oxide semiconductor film is selectively etched to form a third oxide semiconductor film, and a second oxide insulating film is formed. The second oxide insulating film is selectively etched and a protective film covering an end portion of the third oxide semiconductor film is formed. Then, a pair of electrodes, a gate insulating film, and a gate electrode are formed over the third oxide semiconductor film and the protective film.

Claims

1. A semiconductor device comprising:

an oxide semiconductor layer,

a gate insulating layer over the oxide semiconductor layer,

a gate electrode over the oxide semiconductor layer with the gate insulating layer interposed therebetween,

a first electrode over and in contact with the oxide semiconductor layer,

an insulating layer over the oxide semiconductor layer, the gate electrode, and the first electrode, and

a second electrode over and in contact with the first electrode,

wherein, in a channel width direction, a width of the first electrode is smaller than a width of the oxide semiconductor layer, and a width of the second electrode is smaller than the width of the first electrode.

2. The semiconductor device according to claim 1, wherein an edge of the oxide semiconductor layer protrudes from an edge of the gate insulating layer.

3. The semiconductor device according to claim 1, wherein each edge of the gate insulating layer and the gate electrode is a tapered shape.

4. The semiconductor device according to claim 1, wherein the oxide semiconductor layer is a non-single-crystal layer including a c-axis-aligned crystalline region.

5. The semiconductor device according to claim 1, wherein the oxide semiconductor layer includes a first oxide semiconductor region overlapping with the gate electrode, a pair of second oxide semiconductor regions sandwiching the first oxide semiconductor region, and a pair of third oxide semiconductor regions which overlaps with the second electrode and sandwiches the pair of second oxide semiconductor regions.

6. The semiconductor device according to claim 5,

wherein the first oxide semiconductor region is a channel region,

wherein the pair of second oxide semiconductor regions is electric-field relaxation regions, and

wherein the pair of third oxide semiconductor regions is a source and a drain region.

7. The semiconductor device according to claim 5, wherein the pair of second oxide semiconductor regions includes at least one element selected from nitrogen, phosphorus, and arsenic at a concentration higher than or equal to 5×

10¹⁸ atoms/cm³ and lower than or equal to 1×

10²² atoms/cm³.

8. The semiconductor device according to claim 5, wherein the pair of second oxide semiconductor regions includes at least one dopant selected from hydrogen, helium, neon, argon, krypton, and xenon at a concentration higher than or equal to 5×

10¹⁸ atoms/cm³ and lower than or equal to 1×

10²² atoms/cm³.

9. The semiconductor device according to claim 1, wherein the oxide semiconductor layer includes at least one element selected from In, Ga, Sn, and Zn.

10. The semiconductor device according to claim 1, further comprising a light-emitting element.

11. A semiconductor device comprising:

an oxide semiconductor layer,

a gate insulating layer over the oxide semiconductor layer,

a gate electrode over the oxide semiconductor layer with the gate insulating layer interposed therebetween,

a first electrode over and in contact with the oxide semiconductor layer,

an insulating layer over the oxide semiconductor layer, the gate electrode, and the first electrode, and

a second electrode over and in contact with the first electrode,

wherein a length of the gate insulating layer at a portion in contact with the oxide semiconductor layer is longer than a length of the gate insulating layer at a portion in contact with the gate electrode, and

wherein, in a channel width direction, a width of the first electrode is smaller than a width of the oxide semiconductor layer, and a width of the second electrode is smaller than the width of the first electrode.

12. The semiconductor device according to claim 11, wherein an edge of the oxide semiconductor layer protrudes from an edge of the gate insulating layer.

13. The semiconductor device according to claim 11, wherein each edge of the gate insulating layer and the gate electrode is a tapered shape.

14. The semiconductor device according to claim 11, wherein the oxide semiconductor layer is a non-single-crystal layer including a c-axis-aligned crystalline region.

15. The semiconductor device according to claim 11, wherein the oxide semiconductor layer includes a first oxide semiconductor region overlapping with the gate electrode, a pair of second oxide semiconductor regions sandwiching the first oxide semiconductor region, and a pair of third oxide semiconductor regions which overlaps with the second electrode and sandwiches the pair of second oxide semiconductor regions.

16. The semiconductor device according to claim 15,

wherein the first oxide semiconductor region is a channel region,

wherein the pair of second oxide semiconductor regions is electric-field relaxation regions, and

wherein the pair of third oxide semiconductor regions is a source and a drain region.

17. The semiconductor device according to claim 15, wherein the pair of second oxide semiconductor regions includes at least one element selected from nitrogen, phosphorus, and arsenic at a concentration higher than or equal to 5×

10¹⁸ atoms/cm³ and lower than or equal to 1×

10²² atoms/cm³.

18. The semiconductor device according to claim 15, wherein the pair of second oxide semiconductor regions includes at least one dopant selected from hydrogen, helium, neon, argon, krypton, and xenon at a concentration higher than or equal to 5×

10¹⁸ atoms/cm³ and lower than or equal to 1×

10²² atoms/cm³.

19. The semiconductor device according to claim 11, wherein the oxide semiconductor layer includes at least one element selected from In, Ga, Sn, and Zn.

20. The semiconductor device according to claim 11, further comprising a light-emitting element.