Semiconductor device

Patent metadata

Field	Value
Publication number	US-2020006567-A1
Application number	US-201816484148-A
Country	US
Kind code	A1
Filing date	Feb 7, 2018
Priority date	Feb 15, 2017
Publication date	Jan 2, 2020
Grant date	—

Abstract

The semiconductor device includes a first oxide; a second oxide over the first oxide; a source electrode and a drain electrode over the second oxide; a third oxide over the second oxide, the source electrode, and the drain electrode; a fourth oxide over the third oxide; a gate insulating film over the fourth oxide; and a gate electrode over the gate insulating film. The band gap of the first oxide is substantially the same as the band gap of the fourth oxide, the band gap of the second oxide is substantially the same as the band gap of the third oxide, the band gap of the first oxide is larger than the band gap of the second oxide, and the fourth oxide is less likely to transmit oxygen than the third oxide.

First claim

1 . A semiconductor device comprising:
a first oxide; a second oxide over the first oxide; a source electrode and a drain electrode over the second oxide; a third oxide over the second oxide, the source electrode, and the drain electrode; a fourth oxide over the third oxide; a gate insulating film over the fourth oxide; and a gate electrode over the gate insulating film, wherein a band gap of the first oxide is substantially the same as a band gap of the fourth oxide, wherein a band gap of the second oxide is substantially the same as a band gap of the third oxide, wherein the band gap of the first oxide is larger than the band gap of the second oxide, and wherein the fourth oxide is less likely to transmit oxygen than the third oxide.

2 . The semiconductor device according to claim 1 ,
wherein the second oxide and the third oxide each comprise a channel formation region, wherein the channel formation region is positioned between the source electrode and the drain electrode, and wherein a height from a bottom surface of the first oxide to each of the channel formation region, the source electrode, and the drain electrode is substantially the same.

3 . The semiconductor device according to claim 1 ,
wherein a difference between the band gap of the first oxide and the band gap of the fourth oxide is less than or equal to 0.15 eV, wherein a difference between the band gap of the second oxide and the band gap of the third oxide is less than or equal to 0.15 eV, and wherein a difference between the band gap of the first oxide and the band gap of the second oxide is greater than or equal to 0.3 eV and less than or equal to 0.7 eV.

4 . The semiconductor device according to claim 1 ,
wherein the first to fourth oxides each comprise In, an element M, and Zn, wherein the element M is Al, Ga, Y, or Sn, wherein the first oxide and the fourth oxide each comprise a region in which a proportion of the element M is higher than a proportion of In, wherein the second oxide and the third oxide each comprise a region in which a proportion of the element M is lower than a proportion of In, wherein the first oxide and the fourth oxide have the same composition or similar compositions, and wherein the second oxide and the third oxide have the same composition or similar compositions.

5 . The semiconductor device according to claim 1 , wherein the fourth oxide is less likely to transmit oxygen than the gate insulating film.

6 . A module characterized by comprising the semiconductor device according to claim 1 and a printed circuit board.

7 . An electronic device comprising the module according to claim 6 , and a speaker or an operation key.

8 . A semiconductor wafer comprising:
a plurality of the semiconductor devices according to claim 1 ; and a region for dicing.

9 . A method for fabricating a semiconductor device comprising:
forming a first oxide by a sputtering method using a first target; forming a second oxide over the first oxide by the sputtering method using a second target; forming a first conductor and a second conductor over the second oxide; forming a third oxide over the second oxide, the first conductor, and the second conductor by the sputtering method using a third target; forming a fourth oxide over the third oxide by the sputtering method using a fourth target; forming an insulator over the fourth oxide; and forming a third conductor over the insulator, wherein the first to fourth targets each comprise two or more kinds of metal elements, wherein an atomic ratio of the metal elements in the first target and an atomic ratio of the metal elements in the fourth target are the same or similar to each other, and wherein an atomic ratio of the metal elements in the second target and an atomic ratio of the metal elements in the third target are the same or similar to each other.

10 . The method according to claim 9 ,
wherein the first target and the fourth target each comprise In, an element M, and Zn, wherein the element M is Al, Ga, Y, or Sn, wherein the number of In atoms are less than the number of the element M atoms, wherein the second target and the third target each comprise In, the element M, and Zn, wherein the element M is Al, Ga, Y, or Sn, and wherein the number of In atoms are greater than the number of the element M atoms.

11 . The method according to claim 9 ,
wherein the first oxide and the second oxide are formed under a reduced pressure in an order of the first oxide and the second oxide, and wherein the third oxide and the fourth oxide are formed under the reduced pressure in an order of the third oxide and the fourth oxide.

12 . A module comprising a semiconductor device fabricated using the method according to claim 9 , and a printed circuit board.

13 . An electronic device comprising the module according to claim 12 , and a speaker or an operation key.

Assignees

• Semiconductor Energy Lab

Inventors

• Endo Yuta
• Sawai Hiromi
• Kimura Hajime
• Yamazaki Shunpei

Classifications

• H10P14/3434

  being oxide semiconductor materials (Group IIB-VIA semiconductor materials H10P14/3424) · CPC title

• H10P14/3426

  Oxides · CPC title

• H10P14/3234

  being oxide semiconducting materials (Group IIB-VIA semiconductors H10P14/3224) · CPC title

• H10P14/22

  using physical deposition, e.g. vacuum deposition or sputtering · CPC title

• H01L29/7869 Primary

  Electricity · mapped topic