Semiconductor device with oxide semiconductor film

• US 9,356,098 B2
• Filed: 12/18/2014
• Issued: 05/31/2016
• Est. Priority Date: 12/27/2013
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei, Koezuka, Junichi, Jintyou, Masami, Shima, Yukinori, Hamochi, Takashi, Nakazawa, Yasutaka
• Primary Examiner(s): Huynh, Andy
• Application Number:
  US14/574,424
• Publication Number:
  US 20150187878A1
• Time in Patent Office: 530 Days
• Field of Search: 257/43, 257/59, 257/E21.409
• US Class Current: 1/1
• CPC Class Codes: G02F 1/133345 Insulating layers G02F1/1335, G02F1/1337, G02F1/135, G02F1/136 take precedence
• CPC Class Codes: G02F 1/133512 Light shielding layers, e.g. black matrix G02F1/136209 takes precedence
• CPC Class Codes: G02F 1/133514 Colour filters
• CPC Class Codes: G02F 1/13394 spacers regularly patterned on the cell subtrate, e.g. walls, pillars G02F1/133377 takes precedence
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence
• 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 27/1233 with different thicknesses of the active layer 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 27/1251 comprising TFTs having a different architecture, e.g. top- and bottom gate TFTs
• 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 29/45 Ohmic electrodes
• CPC Class Codes: H01L 29/78606 with supplementary region or layer in the thin film or in the insulated bulk substrate supporting it for controlling or increasing the safety of the device H01L29/78642, H01L29/78645 take precedence
• CPC Class Codes: H01L 29/78648 arranged on opposing sides of the channel
• 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 29/78696 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

Abstract

To provide a semiconductor device including a transistor in which an oxide semiconductor is used and on-state current is high. In a semiconductor device including a first transistor provided in a driver circuit portion and a second transistor provided in a pixel portion, the first transistor and the second transistor have different structures. Furthermore, the first transistor and the second transistor are transistors having a top-gate structure in which conductive films serving as a gate electrode, a source electrode, and a drain electrode do not overlap. Furthermore, in an oxide semiconductor film, an impurity element is contained in a region which does not overlap with the gate electrode, the source electrode, and the drain electrode.

Claims

1. A semiconductor device comprising:

a first transistor comprising;

a first gate electrode over an insulating surface;

a first insulating film over the first gate electrode;

a first oxide semiconductor film over the first insulating film;

a pair of first conductive films in contact with the first oxide semiconductor film;

a second insulating film over the first oxide semiconductor film; and

a second gate electrode over the second insulating film,

a second transistor comprising;

a second oxide semiconductor film over the first insulating film;

a pair of second conductive films in contact with the second oxide semiconductor film;

the second insulating film over the second oxide semiconductor film; and

a third gate electrode over the second insulating film,

wherein the first oxide semiconductor film comprises an impurity element in a first region that does not overlap with the second gate electrode and the pair of first conductive films, and

wherein the second oxide semiconductor film comprises the impurity element in a second region that does not overlap with the third gate electrode and the pair of second conductive films.

2. The semiconductor device according to claim 1,

wherein the first oxide semiconductor film and the second oxide semiconductor film each have a multilayer structure including a first film and a second film, and

wherein the first film differs from the second film in an atomic ratio of metal elements.

3. The semiconductor device according to claim 1,

wherein the first oxide semiconductor film and the second oxide semiconductor film each have a multilayer structure in which a first film, a second film, and a third film are stacked, and

wherein the second film differs from the first film and the third film in an atomic ratio of metal elements.

4. The semiconductor device according to claim 1,

wherein, in the first oxide semiconductor film, an impurity element concentration of the first region is higher than an impurity element concentration of a third region overlapping with the second gate electrode and is higher than or equal to 1×

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

10²² atoms/cm³, and

wherein, in the second oxide semiconductor film, an impurity element concentration of the second region is higher than an impurity element concentration of a fourth region overlapping with the third gate electrode and is higher than or equal to 1×

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

10²² atoms/cm³.

5. The semiconductor device according to claim 1,

wherein, in the first oxide semiconductor film, a hydrogen concentration of the first region is higher than a hydrogen concentration of a third region overlapping with the second gate electrode and is higher than or equal to 8×

10¹⁹ atoms/cm³, and

wherein, in the second oxide semiconductor film, a hydrogen concentration of the second region is higher than a hydrogen concentration of a fourth region overlapping with the third gate electrode and is higher than or equal to 8×

10¹⁹ atoms/cm³.

6. The semiconductor device according to claim 1,

wherein the impurity element is at least one of hydrogen, boron, carbon, nitrogen, fluorine, aluminum, silicon, phosphorus, chlorine, and a rare gas element.

7. The semiconductor device according to claim 1, further comprising a film containing hydrogen,

wherein the film is in contact with the first region and the second region.

8. The semiconductor device according to claim 7, wherein the film is a nitride insulating film.

9. The semiconductor device according to claim 1,

wherein the pair of first conductive films and the pair of second conductive films comprise metal silicide or metal silicide-nitride.

10. The semiconductor device according to claim 1,

wherein the first transistor is provided in a driver circuit portion, and

wherein the second transistor is provided in a pixel portion.

11. A semiconductor device comprising:

a first transistor comprising;

a first oxide semiconductor film over an insulating surface;

a pair of first conductive films in contact with the first oxide semiconductor film;

a first insulating film over the first oxide semiconductor film; and

a first gate electrode over the first insulating film,

a second transistor comprising;

a second oxide semiconductor film over the insulating surface;

a pair of second conductive films in contact with the second oxide semiconductor film;

the first insulating film in contact with the second oxide semiconductor film; and

a second gate electrode over the first insulating film,

wherein the first oxide semiconductor film comprises an impurity element in a first region that does not overlap with the first gate electrode and the pair of first conductive films,

wherein the second oxide semiconductor film comprises the impurity element in a second region that does not overlap with the second gate electrode and the pair of second conductive films,

wherein the first oxide semiconductor film comprises a first film and a second film over the first film, and

wherein the second oxide semiconductor film differs from the first film in an atomic ratio of metal elements.

12. The semiconductor device according to claim 11,

wherein the atomic ratio of metal elements of the second oxide semiconductor film is the same as an atomic ratio of metal elements of the second film.

13. The semiconductor device according to claim 11,

wherein an edge portion of the second film is positioned on an outer side than an edge portion of the first film.

14. The semiconductor device according to claim 11,

wherein the first transistor comprises a third gate electrode and a second insulating film between the insulating surface and the first oxide semiconductor film.

15. The semiconductor device according to claim 11,

wherein, in the first oxide semiconductor film, an impurity element concentration of the first region is higher than an impurity element concentration of a third region overlapping with the first gate electrode and is higher than or equal to 1×

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

10²² atoms/cm³, and

wherein, in the second oxide semiconductor film, an impurity element concentration of the second region is higher than an impurity element concentration of a fourth region overlapping with the second gate electrode and is higher than or equal to 1×

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

10²² atoms/cm³.

16. The semiconductor device according to claim 11,

wherein, in the first oxide semiconductor film, a hydrogen concentration of the first region is higher than a hydrogen concentration of a third region overlapping with the first gate electrode and is higher than or equal to 8×

10¹⁹ atoms/cm³, and

wherein, in the second oxide semiconductor film, a hydrogen concentration of the second region is higher than a hydrogen concentration of a fourth region overlapping with the second gate electrode and is higher than or equal to 8×

10¹⁹ atoms/cm³.

17. The semiconductor device according to claim 11,

wherein the impurity element is at least one of hydrogen, boron, carbon, nitrogen, fluorine, aluminum, silicon, phosphorus, chlorine, and a rare gas element.

18. The semiconductor device according to claim 11, further comprising a film containing hydrogen,

wherein the film is in contact with the first region and the second region.

19. The semiconductor device according to claim 18, wherein the film is a nitride insulating film.

20. The semiconductor device according to claim 11,

wherein the pair of first conductive films and the pair of second conductive films comprise metal silicide or metal silicide-nitride.

21. The semiconductor device according to claim 11,

wherein the first transistor is provided in a driver circuit portion, and

wherein the second transistor is provided in a pixel portion.