SEMICONDUCTOR DEVICE AND METHOD FOR MANUFACTURING THE SAME

• US 20110127522A1
• Filed: 11/22/2010
• Published: 06/02/2011
• 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
• Granted Patent: US 8,367,489 B2
• Time in Patent Office: Days
• US Class Current: 257/43
• 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 manufacturing method of a semiconductor device comprising the steps of:

forming a first electrode over a substrate;

forming a first oxide semiconductor film over the first electrode;

performing first heat treatment to the first oxide semiconductor film to cause crystal growth from a surface to an inside portion of the first oxide semiconductor film;

forming a second oxide semiconductor film over the first oxide semiconductor film;

performing second heat treatment to the second oxide semiconductor film to cause crystal growth in the second oxide semiconductor film;

etching the first oxide semiconductor film and the second oxide semiconductor film so as to have an island shape;

forming a second electrode over the second oxide semiconductor film;

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

forming a gate electrode over the gate insulating film.

2. The manufacturing method of the semiconductor device according to claim 1, wherein the crystal growth in the second oxide semiconductor film is caused with the use of the first oxide semiconductor film as a seed crystal.

3. The manufacturing method of the semiconductor device according to claim 1,

wherein the first oxide semiconductor film is c-axis aligned in a direction perpendicular to the surface, and

wherein the second oxide semiconductor film is c-axis aligned in the direction perpendicular to the surface.

4. The manufacturing method of the semiconductor device according to claim 1,

wherein the first oxide semiconductor film has single crystal regions, and

wherein the second oxide semiconductor film has single crystal regions.

5. The manufacturing method of the semiconductor device according to claim 1, wherein the first oxide semiconductor film has a thickness greater than or equal to 2 nm and less than or equal to 15 nm

6. The manufacturing method of the semiconductor device according to claim 1,

wherein the first oxide semiconductor film is deposited by a sputtering method and a metal oxide target for the deposition has a composition ratio of In:

Ga;

Zn=1;

greater than or equal to 0 and less than or equal to 2;

greater than or equal to 1 and less than or equal to 5, and

wherein the second oxide semiconductor film is deposited over the first oxide semiconductor film by a sputtering method and a metal oxide target for the deposition has a composition ratio of In;

Ga;

Zn=1;

greater than or equal to 0 and less than or equal to 2;

greater than or equal to 1 and less than or equal to 5.

7. The manufacturing method of the semiconductor device according to claim 1, wherein the first oxide semiconductor film and the second oxide semiconductor film are homoepitaxially grown.

8. The manufacturing method of the semiconductor device according to claim 1, wherein the first oxide semiconductor film and the second oxide semiconductor film are heteroepitaxially grown.

9. The manufacturing method of the semiconductor device according to claim 1, wherein the first oxide semiconductor film and the second oxide semiconductor film are dehydrated or dehydrogenated.

10. The manufacturing method of the semiconductor device according to claim 1, wherein the first oxide semiconductor film and the second oxide semiconductor film have carrier density lower than 1×

10¹² cm<sup>−

3</sup>.

11. The manufacturing method of the semiconductor device according to claim 1, wherein the first oxide semiconductor film and the second oxide semiconductor film have carrier density lower than 1.4×

10¹⁰ cm<sup>−

3</sup>.

12. The manufacturing method of the semiconductor device according to claim 1, wherein the first oxide semiconductor film and the second oxide semiconductor film comprise an intrinsic semiconductor.

13. The manufacturing method of the semiconductor device according to claim 1, wherein the semiconductor device has a transistor or a diode.

14. A manufacturing method of a semiconductor device comprising the steps of:

forming a first electrode over a substrate;

forming a first oxide semiconductor film over the first electrode;

performing first heat treatment to the first oxide semiconductor film to cause crystal growth from a surface to an inside portion of the first oxide semiconductor film;

forming a second oxide semiconductor film over the first oxide semiconductor film;

forming a conductive film over the second oxide semiconductor film;

performing second heat treatment to the second oxide semiconductor film to cause crystal growth in the second oxide semiconductor film;

forming a second electrode by etching the conductive film;

etching the first oxide semiconductor film and the second oxide semiconductor film so as to have an island shape;

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

forming a gate electrode over the gate insulating film.

15. A manufacturing method of a semiconductor device comprising the steps of:

forming a first electrode over a substrate;

forming a first oxide semiconductor film over the first electrode;

performing first heat treatment to the first oxide semiconductor film to cause crystal growth from a surface to an inside portion of the first oxide semiconductor film;

forming a second oxide semiconductor film having crystallinity over the first oxide semiconductor film by a sputtering method while heating is performed;

etching the first oxide semiconductor film and the second oxide semiconductor film so as to have an island shape;

forming a second electrode over the second oxide semiconductor film;

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

forming a gate electrode over the gate insulating film.

16. A semiconductor device comprising:

a first electrode formed over a substrate;

a stacked body of an oxide semiconductor formed over the first electrode, the stacked body comprising;

a first oxide semiconductor film having crystallinity with a crystal grown from a surface to an inside portion; and

a second oxide semiconductor film having crystallinity over the first oxide semiconductor film;

a second electrode formed over the stacked body of the oxide semiconductor;

a gate insulating film covering the first electrode, the stacked body of the oxide semiconductor, and the second electrode; and

a third electrode having a ring shape and facing at least a side surface of the stacked body of the oxide semiconductor with the gate insulating film provided therebetween.

17. The semiconductor device according to claim 16, wherein the second electrode is in contact with an entire top surface of the stacked body of the oxide semiconductor.

18. The semiconductor device according to claim 16,

wherein the first electrode functions as one of a source electrode and a drain electrode,

wherein the second electrode functions as the other of the source electrode and the drain electrode, and

wherein the third electrode functions as a gate electrode.

19. The semiconductor device according to claim 16,

wherein the first oxide semiconductor film having crystallinity is c-axis aligned in a direction perpendicular to the surface, and

wherein the second oxide semiconductor film having crystallinity is c-axis aligned in the direction perpendicular to the surface.

20. The semiconductor device according to claim 16, wherein the first oxide semiconductor film having crystallinity has an average thickness greater than or equal to 2 nm and less than or equal to 15 nm.

21. The semiconductor device according to claim 16, wherein a material of the first oxide semiconductor film having crystallinity and a material of the second oxide semiconductor film having crystallinity contain the same components.

22. The semiconductor device according to claim 16, wherein the first oxide semiconductor film having crystallinity and the second oxide semiconductor film having crystallinity have the same electron affinity.

23. The semiconductor device according to claim 16, wherein the first oxide semiconductor film having crystallinity and the second oxide semiconductor film having crystallinity have a homoepitaxial structure.

24. The semiconductor device according to claim 16, wherein a material of the first oxide semiconductor film having crystallinity and a material of the second oxide semiconductor film having crystallinity are different from each other.

25. The semiconductor device according to claim 16, wherein the first oxide semiconductor film having crystallinity and the second oxide semiconductor film having crystallinity have a heteroepitaxial structure.

26. The semiconductor device according to claim 16, wherein the first oxide semiconductor film having crystallinity and the second oxide semiconductor film having crystallinity are dehydrated or dehydrogenated.

27. The semiconductor device according to claim 16, wherein the first oxide semiconductor film having crystallinity and the second oxide semiconductor film having crystallinity have carrier density lower than 1×

10¹² cm<sup>−

3</sup>.

28. The semiconductor device according to claim 16, wherein the first oxide semiconductor film having crystallinity and the second oxide semiconductor film having crystallinity have carrier density lower than 1.4×

10¹⁰ cm<sup>−

3</sup>.

29. The semiconductor device according to claim 16, wherein the first oxide semiconductor film having crystallinity and the second oxide semiconductor film having crystallinity comprise an intrinsic semiconductor.

30. The semiconductor device according to claim 16, wherein the semiconductor device has a transistor or a diode.

31. A semiconductor device comprising:

a first electrode formed over a substrate;

a stacked body of an oxide semiconductor formed over the first electrode, the stacked body comprising;

a first oxide semiconductor film having crystallinity with a crystal grown from a surface to an inside portion; and

a second oxide semiconductor film having crystallinity over the first oxide semiconductor film;

a second electrode being over the stacked body of the oxide semiconductor and being formed inside a periphery of the stacked body of the oxide semiconductor;

a gate insulating film covering the first electrode, the stacked body of the oxide semiconductor, and the second electrode; and

a third electrode having a ring shape and facing at least a side surface of the stacked body of the oxide semiconductor and a side surface of the second electrode with the gate insulating film provided therebetween.