Semiconductor device and memory device

Patent metadata

Field	Value
Publication number	US-2016149055-A1
Application number	US-201514942310-A
Country	US
Kind code	A1
Filing date	Nov 16, 2015
Priority date	Nov 21, 2014
Publication date	May 26, 2016
Grant date	—

Abstract

The present invention provides a transistor having a high on-state current. The transistor includes a plurality of fins, a first oxide semiconductor, a gate insulating film, and a gate electrode. One of adjacent two fins includes a second oxide semiconductor and a third oxide semiconductor. The other includes a fourth oxide semiconductor and the third oxide semiconductor. The second oxide semiconductor and the fourth oxide semiconductor include regions that face each other with the gate electrode positioned therebetween. The gate electrode and the second oxide semiconductor overlap with each other with the gate insulating film and the first oxide semiconductor positioned therebetween. The gate electrode and the fourth oxide semiconductor overlap with each other with the gate insulating film and the first oxide semiconductor positioned therebetween.

First claim

1 . A transistor comprising:
a first oxide semiconductor film over an insulator; a second oxide semiconductor film over the first oxide semiconductor film; a third oxide semiconductor film over the first oxide semiconductor film; a fourth oxide semiconductor film over the first oxide semiconductor film, the second oxide semiconductor film, and the third oxide semiconductor film; a gate insulating film over the fourth oxide semiconductor film; and a gate electrode over the gate insulating film, wherein the second oxide semiconductor film and the third oxide semiconductor film comprise regions that face each other with the gate electrode positioned therebetween.

2 . The transistor according to claim 1 ,
wherein the first to third oxide semiconductor films comprise indium, zinc, and a metal, and wherein the metal is Al, Ti, Ga, Y, Zr, La, Ce, Nd, or Hf.

3 . The transistor according to claim 2 ,
wherein the first oxide semiconductor film and the fourth oxide semiconductor film have a larger atomic ratio of the metal to indium than the second oxide semiconductor film and the third oxide semiconductor film.

4 . The transistor according to claim 1 ,
wherein the forth oxide semiconductor film is in contact with the first oxide semiconductor film.

5 . The transistor according to claim 1 ,
wherein the forth oxide semiconductor film is in contact with the insulator.

6 . An electronic device comprising:
the transistor according to claim 1 ; and at least one of a microphone, a speaker, a display portion, and an operation key.

7 . A transistor comprising:
a first oxide semiconductor film over an insulator; a second oxide semiconductor film over the first oxide semiconductor film; a third oxide semiconductor film over the first oxide semiconductor film; a fourth oxide semiconductor film over the first oxide semiconductor film, the second oxide semiconductor film, and the third oxide semiconductor film; a gate insulating film over the fourth oxide semiconductor film; and a gate electrode over the gate insulating film, wherein the second oxide semiconductor film and the third oxide semiconductor film comprise regions that face each other with the gate electrode positioned therebetween, wherein the gate insulating film comprises a region in contact with a top surface of the fourth oxide semiconductor film, wherein the first oxide semiconductor film comprises a first portion overlapping with the gate electrode with the second oxide semiconductor film positioned therebetween, and wherein the first oxide semiconductor film comprises a second portion overlapping with the gate electrode with the third oxide semiconductor film positioned therebetween.

8 . The transistor according to claim 7 ,
wherein the first to third oxide semiconductor films comprise indium, zinc, and a metal, and wherein the metal is Al, Ti, Ga, Y, Zr, La, Ce, Nd, or Hf.

9 . The transistor according to claim 8 ,
wherein the first oxide semiconductor film and the fourth oxide semiconductor film have a larger atomic ratio of the metal to indium than the second oxide semiconductor film and the third oxide semiconductor film.

10 . The transistor according to claim 7 ,
wherein the forth oxide semiconductor film is in contact with the first oxide semiconductor film.

11 . The transistor according to claim 7 ,
wherein the forth oxide semiconductor film is in contact with the insulator.

12 . An electronic device comprising:
the transistor according to claim 7 ; and at least one of a microphone, a speaker, a display portion, and an operation key.

13 . A transistor comprising:
a first fin to N-th fin, the N being a natural number of 2 or more, wherein the first fin comprises a first oxide semiconductor film and a second oxide semiconductor film, and a second fin comprises a third oxide semiconductor film and a fourth oxide semiconductor film; a fifth oxide semiconductor film over the first fin and the second fin; a gate insulating film over the fifth oxide semiconductor film; and a gate electrode over the gate insulating film, wherein the first oxide semiconductor film and the third oxide semiconductor film comprise regions that face each other with the gate electrode positioned therebetween, wherein the second oxide semiconductor film and the fourth oxide semiconductor film comprise regions that face each other with the gate electrode positioned therebetween, wherein the second oxide semiconductor film comprises a first portion between the first oxide semiconductor film and the fifth oxide semiconductor film, wherein the gate electrode and the first portion overlap with each other with the gate insulating film positioned therebetween, wherein the fourth oxide semiconductor film comprises a second portion between the third oxide semiconductor film and the fifth oxide semiconductor film, and wherein the gate electrode and the second portion overlap with each other with the gate insulating film positioned therebetween.

14 . The transistor according to claim 13 ,
wherein the first to third oxide semiconductor films comprise indium, zinc, and a metal, and wherein the metal is Al, Ti, Ga, Y, Zr, La, Ce, Nd, or Hf.

15 . The transistor according to claim 14 ,
wherein the first, third, and fifth oxide semiconductors have a larger atomic ratio of the metal to indium than the second and fourth oxide semiconductors.

16 . A memory comprising:
the transistor according to claim 13 ; and a capacitor connected to an electrode of the transistor, wherein the N divided by load capacitance of the capacitor is larger than or equal to 2×10 12 F −1 and smaller than or equal to 200×10 15 F −1 .

17 . An electronic device comprising:
the transistor according to claim 13 ; and at least one of a microphone, a speaker, a display portion, and an operation key.

Assignees

• Semiconductor Energy Lab

Inventors

• Yamazaki Shunpei
• Tsutsui Kazuhiro
• Matsuda Shinpei

Classifications

• H10D30/6757 Primary

  characterised by the structure of the channel, e.g. transverse or longitudinal shape or doping profile (TFTs having channel structures for preventing kink or snapback effects H10D30/6708; TFTs having lightly-doped source or drain extensions H10D30/6715) · CPC title

• H10D30/6212

  having fin-shaped semiconductor bodies having non-rectangular cross-sections · CPC title

• H10D30/0245

  by further thinning the channel after patterning the channel, e.g. using sacrificial oxidation on fins · CPC title

• H10D62/80

  characterised by the materials · CPC title

• H10D86/60

  wherein the TFTs are in active matrices · CPC title