Transistor and display device

• US 9,368,641 B2
• Filed: 08/06/2015
• Issued: 06/14/2016
• Est. Priority Date: 09/04/2009
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei, Sasaki, Toshinari, Sakata, Junichiro, Tsubuku, Masashi
• Primary Examiner(s): Pham, Thanh V
• Application Number:
  US14/819,801
• Publication Number:
  US 20160035902A1
• Time in Patent Office: 313 Days
• US Class Current: 1/1
• 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 27/1248 with a particular composition or shape of the interlayer dielectric specially adapted to the circuit arrangement
• CPC Class Codes: H01L 27/1255 integrated with passive devices, e.g. auxiliary capacitors
• 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 29/42356 Disposition, e.g. buried gate electrode H01L29/42324 and H01L29/4234 take precedence
• CPC Class Codes: H01L 29/45 Ohmic electrodes
• 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 29/78606 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 29/78618 characterised by the drain or the source properties, e.g. the doping structure, the composition, the sectional shape or the contact structure silicide contacts, electrodes in general H01L29/458
• 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: H10K 59/1213 the pixel elements being TFTs
• CPC Class Codes: H10K 59/1216 the pixel elements being capacitors
• CPC Class Codes: H10K 59/123 Connection of the pixel electrodes to the thin film transistors [TFT]

Abstract

It is an object to manufacture a highly reliable display device using a thin film transistor having favorable electric characteristics and high reliability as a switching element. In a bottom gate thin film transistor including an amorphous oxide semiconductor, an oxide conductive layer having a crystal region is formed between an oxide semiconductor layer which has been dehydrated or dehydrogenated by heat treatment and each of a source electrode layer and a drain electrode layer which are formed using a metal material. Accordingly, contact resistance between the oxide semiconductor layer and each of the source electrode layer and the drain electrode layer can be reduced; thus, a thin film transistor having favorable electric characteristics and a highly reliable display device using the thin film transistor can be provided.

Claims

1. A semiconductor device comprising:

a first conductive film;

a first insulating film over the first conductive film;

an oxide semiconductor film comprising first to fifth regions over the first insulating film;

a second insulating film over the oxide semiconductor film;

a second electrode over and in contact with the oxide semiconductor film;

a third electrode over and in contact with the oxide semiconductor film; and

a third insulating film over the second insulating film and in contact with the oxide semiconductor film,

wherein the oxide semiconductor film comprises indium and zinc,

wherein the first region of the oxide semiconductor film is positioned between the second region and the third region of the oxide semiconductor film,

wherein the fourth region of the oxide semiconductor film is positioned between the first region and the second region of the oxide semiconductor film,

wherein the fifth region of the oxide semiconductor film is positioned between the first region and the third region of the oxide semiconductor film,

wherein the second electrode is in contact with the second region of the oxide semiconductor film,

wherein the third electrode is in contact with the third region of the oxide semiconductor film,

wherein the third insulating film is in contact with the fourth region and the fifth region of the oxide semiconductor film,

wherein the third insulating film is a nitride insulating film,

wherein the first region of the oxide semiconductor film is a channel formation region, and

wherein each of the second to fifth region of the oxide semiconductor film has lower resistance than the first region of the oxide semiconductor film.

2. The semiconductor device according to claim 1, wherein the oxide semiconductor film comprises gallium.

3. The semiconductor device according to claim 1, wherein the third insulating film is positioned over the second electrode and the third electrode.

4. The semiconductor device according to claim 1, wherein a top surface of the second insulating film is in contact with the third insulating film.

5. The semiconductor device according to claim 1, wherein the oxide semiconductor film is in an amorphous state.

6. The semiconductor device according to claim 1,

wherein the oxide semiconductor film comprises a sixth region and the seventh region,

wherein the second region of the oxide semiconductor film is positioned between the fourth region and the sixth region of the oxide semiconductor film,

wherein the third region of the oxide semiconductor film is positioned between the fifth region and the seventh region of the oxide semiconductor film, and

wherein each of the sixth region and the seventh region of the oxide semiconductor film is in an oxygen-excess state.

7. The semiconductor device according to claim 1, wherein each of the second electrode and the third electrode is an oxide conductive film.

8. The semiconductor device according to claim 1, wherein each of the second electrode and the third electrode comprises a crystalline region.

9. A semiconductor device comprising:

a first conductive film;

a first insulating film over the first conductive film;

an oxide semiconductor film comprising first to fifth regions over the first insulating film;

a second insulating film over the oxide semiconductor film;

a second electrode over and in contact with the oxide semiconductor film;

a third electrode over and in contact with the oxide semiconductor film; and

a third insulating film over the second insulating film and in contact with the oxide semiconductor film,

wherein the oxide semiconductor film comprises indium and zinc,

wherein the first region of the oxide semiconductor film is positioned between the second region and the third region of the oxide semiconductor film,

wherein the fourth region of the oxide semiconductor film is positioned between the first region and the second region of the oxide semiconductor film,

wherein the fifth region of the oxide semiconductor film is positioned between the first region and the third region of the oxide semiconductor film,

wherein the second electrode is in contact with the second region of the oxide semiconductor film,

wherein the third electrode is in contact with the third region of the oxide semiconductor film,

wherein the third insulating film is in contact with the fourth region and the fifth region of the oxide semiconductor film,

wherein the third insulating film is a nitride insulating film,

wherein the first region of the oxide semiconductor film is a channel formation region,

wherein each of the second to fifth region of the oxide semiconductor film has lower resistance than the first region of the oxide semiconductor film, and

wherein the first region of the oxide semiconductor film is in an oxygen-excess state.

10. The semiconductor device according to claim 9, wherein the oxide semiconductor film comprises gallium.

11. The semiconductor device according to claim 9, wherein the third insulating film is positioned over the second electrode and the third electrode.

12. The semiconductor device according to claim 9, wherein a top surface of the second insulating film is in contact with the third insulating film.

13. The semiconductor device according to claim 9, wherein the oxide semiconductor film is in an amorphous state.

14. The semiconductor device according to claim 9,

wherein the oxide semiconductor film comprises a sixth region and the seventh region,

wherein the second region of the oxide semiconductor film is positioned between the fourth region and the sixth region of the oxide semiconductor film,

wherein the third region of the oxide semiconductor film is positioned between the fifth region and the seventh region of the oxide semiconductor film, and

wherein each of the sixth region and the seventh region of the oxide semiconductor film is in an oxygen-excess state.

15. The semiconductor device according to claim 9, wherein each of the second electrode and the third electrode is an oxide conductive film.

16. The semiconductor device according to claim 9, wherein each of the second electrode and the third electrode comprises a crystalline region.

17. A semiconductor device comprising:

a first conductive film;

a first insulating film over the first conductive film;

an oxide semiconductor film comprising first to fifth regions over the first insulating film;

a second insulating film over the oxide semiconductor film;

a second electrode over and in contact with the oxide semiconductor film;

a third electrode over and in contact with the oxide semiconductor film; and

a third insulating film over the second insulating film and in contact with the oxide semiconductor film,

wherein the oxide semiconductor film comprises indium and zinc,

wherein the first region of the oxide semiconductor film is positioned between the second region and the third region of the oxide semiconductor film,

wherein the fourth region of the oxide semiconductor film is positioned between the first region and the second region of the oxide semiconductor film,

wherein the fifth region of the oxide semiconductor film is positioned between the first region and the third region of the oxide semiconductor film,

wherein the second electrode is in contact with the second region of the oxide semiconductor film,

wherein the third electrode is in contact with the third region of the oxide semiconductor film,

wherein the third insulating film is in contact with the fourth region and the fifth region of the oxide semiconductor film,

wherein the third insulating film is a nitride insulating film,

wherein the first region of the oxide semiconductor film is a channel formation region,

wherein each of the second to fifth region of the oxide semiconductor film has lower resistance than the first region of the oxide semiconductor film,

wherein the first region of the oxide semiconductor film is in an oxygen-excess state, and

wherein each of the fourth region and the fifth region of the oxide semiconductor film is an oxygen-deficient region.

18. The semiconductor device according to claim 17, wherein the oxide semiconductor film comprises gallium.

19. The semiconductor device according to claim 17, wherein the third insulating film is positioned over the second electrode and the third electrode.

20. The semiconductor device according to claim 17, wherein a top surface of the second insulating film is in contact with the third insulating film.

21. The semiconductor device according to claim 17, wherein the oxide semiconductor film is in an amorphous state.

22. The semiconductor device according to claim 17,

wherein the oxide semiconductor film comprises a sixth region and the seventh region,

wherein the second region of the oxide semiconductor film is positioned between the fourth region and the sixth region of the oxide semiconductor film,

wherein the third region of the oxide semiconductor film is positioned between the fifth region and the seventh region of the oxide semiconductor film, and

wherein each of the sixth region and the seventh region of the oxide semiconductor film is in an oxygen-excess state.

23. The semiconductor device according to claim 17, wherein each of the second electrode and the third electrode is an oxide conductive film.

24. The semiconductor device according to claim 17, wherein each of the second electrode and the third electrode comprises a crystalline region.