Transistor with stacked oxide semiconductor films

• US 9,368,640 B2
• Filed: 03/18/2014
• Issued: 06/14/2016
• Est. Priority Date: 11/28/2009
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei
• Primary Examiner(s): Chambliss, Alonzo
• Application Number:
  US14/217,988
• Publication Number:
  US 20140197407A1
• Time in Patent Office: 819 Days
• US Class Current: 1/1
• CPC Class Codes: H01L 21/02472 Oxides
• CPC Class Codes: H01L 21/02483 Oxide semiconducting materials not being Group 12/16 materials, e.g. ternary compounds
• CPC Class Codes: H01L 21/02554 Oxides
• CPC Class Codes: H01L 21/02565 Oxide semiconducting materials not being Group 12/16 materials, e.g. ternary compounds
• CPC Class Codes: H01L 21/02631 Physical deposition at reduced pressure, e.g. MBE, sputtering, evaporation
• CPC Class Codes: H01L 21/02634 Homoepitaxy
• CPC Class Codes: H01L 21/02667 Crystallisation or recrystallisation of non-monocrystalline semiconductor materials, e.g. regrowth
• 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 29/045 by their particular orientation of crystalline planes
• CPC Class Codes: H01L 29/247 Amorphous materials
• CPC Class Codes: H01L 29/66666 Vertical transistors H01L29/66712, H01L29/66742 take precedence
• 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 29/78642 Vertical transistors
• 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 33/305 characterised by the doping materials

Abstract

Objects are to provide a semiconductor device for high power application in which a novel semiconductor material having high productivity is used and to provide a semiconductor device having a novel structure in which a novel semiconductor material is used. The present invention is a vertical transistor and a vertical diode each of which has a stacked body of an oxide semiconductor in which a first oxide semiconductor film having crystallinity and a second oxide semiconductor film having crystallinity are stacked. An impurity serving as an electron donor (donor) which is contained in the stacked body of an oxide semiconductor is removed in a step of crystal growth; therefore, the stacked body of an oxide semiconductor is highly purified and is an intrinsic semiconductor or a substantially intrinsic semiconductor whose carrier density is low. The stacked body of an oxide semiconductor has a wider band gap than a silicon semiconductor.

Claims

1. A semiconductor device comprising:

a transistor comprising;

a stacked body comprising;

a first oxide semiconductor film; and

a second oxide semiconductor film on and in contact with the first oxide semiconductor film;

a gate insulating film covering the first oxide semiconductor film and the second oxide semiconductor film; and

a gate electrode over the gate insulating film and facing at least a side surface of the second oxide semiconductor film,

wherein each of the first oxide semiconductor film and the second oxide semiconductor film comprises indium and zinc.

2. The semiconductor device according to claim 1, wherein the gate electrode surrounds the side surface of the second oxide semiconductor film with the gate insulating film located therebetween.

3. The semiconductor device according to claim 1, further comprising a first electrode and a second electrode,

wherein the first oxide semiconductor film is located over the first electrode,

wherein the second electrode is located over the second oxide semiconductor film, and

wherein the gate insulating film covers the first electrode and the second electrode.

4. The semiconductor device according to claim 1, wherein a lower surface of the stacked body is larger than an upper surface of the stacked body.

5. The semiconductor device according to claim 1, wherein each of the first oxide semiconductor film and the second oxide semiconductor film comprises gallium.

6. A semiconductor device comprising:

a transistor comprising;

a stacked body comprising;

a first oxide semiconductor film; and

a second oxide semiconductor film on and in contact with the first oxide semiconductor film;

a gate insulating film covering the first oxide semiconductor film and the second oxide semiconductor film; and

a gate electrode over the gate insulating film and facing at least a side surface of the second oxide semiconductor film,

wherein each of the first oxide semiconductor film and the second oxide semiconductor film comprises indium and zinc, and

wherein the second oxide semiconductor film comprises a crystalline region.

7. The semiconductor device according to claim 6, wherein the gate electrode surrounds the side surface of the second oxide semiconductor film with the gate insulating film located therebetween.

8. The semiconductor device according to claim 6, further comprising a first electrode and a second electrode,

wherein the first oxide semiconductor film is located over the first electrode,

wherein the second electrode is located over the second oxide semiconductor film, and

wherein the gate insulating film covers the first electrode and the second electrode.

9. The semiconductor device according to claim 6, wherein a lower surface of the stacked body is larger than an upper surface of the stacked body.

10. The semiconductor device according to claim 6, wherein each of the first oxide semiconductor film and the second oxide semiconductor film comprises gallium.

11. The semiconductor device according to claim 6, wherein the first oxide semiconductor film comprises a crystalline region.

12. The semiconductor device according to claim 6, wherein the crystalline region has a plate-like shape.

13. The semiconductor device according to claim 6, wherein the crystalline region is a polycrystalline region.

14. The semiconductor device according to claim 13, wherein the polycrystalline region comprises a plurality of single crystal in each of which a c-axis is aligned.

15. A semiconductor device comprising:

a transistor comprising;

a stacked body comprising;

a first oxide semiconductor film; and

a second oxide semiconductor film on and in contact with the first oxide semiconductor film;

a gate insulating film covering the first oxide semiconductor film and the second oxide semiconductor film; and

a gate electrode over the gate insulating film and facing at least a side surface of the second oxide semiconductor film,

wherein each of the first oxide semiconductor film and the second oxide semiconductor film comprises indium and zinc, and

wherein the second oxide semiconductor film is intrinsic or substantially intrinsic.

16. The semiconductor device according to claim 15, wherein the gate electrode surrounds the side surface of the second oxide semiconductor film with the gate insulating film located therebetween.

17. The semiconductor device according to claim 15, further comprising a first electrode and a second electrode,

wherein the first oxide semiconductor film is located over the first electrode,

wherein the second electrode is located over the second oxide semiconductor film, and

wherein the gate insulating film covers the first electrode and the second electrode.

18. The semiconductor device according to claim 15, wherein a lower surface of the stacked body is larger than an upper surface of the stacked body.

19. The semiconductor device according to claim 15, wherein each of the first oxide semiconductor film and the second oxide semiconductor film comprises gallium.

20. The semiconductor device according to claim 15, wherein the first oxide semiconductor film is intrinsic or substantially intrinsic.

21. The semiconductor device according to claim 15, wherein a concentration of hydrogen in the stacked body is lower than or equal to 1×

10¹⁸ cm<sup>−

3</sup>.

22. The semiconductor device according to claim 15, wherein a concentration of iron is lower than or equal to 1×

10¹⁵ cm<sup>−

3</sup>.

23. The semiconductor device according to claim 15, wherein a concentration of nickel is lower than or equal to 1×

10¹⁵ cm<sup>−

3</sup>.