Method for manufacturing semiconductor device

• US 10,586,869 B2
• Filed: 07/20/2015
• Issued: 03/10/2020
• Est. Priority Date: 09/13/2010
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei, Nonaka, Yusuke, Inoue, Takayuki, Tsubuku, Masashi, Akimoto, Kengo, Miyanaga, Akiharu
• Primary Examiner(s): Hossain, Moazzam
• Assistant Examiner(s): Isaac, Stanetta D
• Application Number:
  US14/803,483
• Publication Number:
  US 20150325704A1
• Time in Patent Office: 1,695 Days
• CPC Class Codes: H01L 23/552 Protection against radiation, e.g. light or electromagnetic waves
• CPC Class Codes: H01L 23/564 Details not otherwise provided for, e.g. protection against moisture getters H01L23/26
• CPC Class Codes: H01L 29/04 characterised by their crystalline structure, e.g. polycrystalline, cubic or particular orientation of crystalline planes characterised by physical imperfections H01L29/30
• 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 29/78606 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 29/7869 having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate
• CPC Class Codes: H01L 29/78696 characterised by the structure of the channel, e.g. multichannel, transverse or longitudinal shape, length or width, doping structure, or the overlap or alignment between the channel and the gate, the source or the drain, or the contacting structure of the channel H01L29/78612 takes precedence; transistors having a drain offset region or a lightly doped drain [LDD] H01L29/78621
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

An object is to manufacture a semiconductor device including an oxide semiconductor film, which has stable electric characteristics and high reliability. A crystalline oxide semiconductor film is formed, without performing a plurality of steps, as follows: by utilizing a difference in atomic weight of plural kinds of atoms included in an oxide semiconductor target, zinc with low atomic weight is preferentially deposited on an oxide insulating film to form a seed crystal including zinc; and tin, indium, or the like with high atomic weight is deposited on the seed crystal while causing crystal growth. Further, a crystalline oxide semiconductor film is formed by causing crystal growth using a seed crystal with a hexagonal crystal structure including zinc as a nucleus, whereby a single crystal oxide semiconductor film or a substantially single crystal oxide semiconductor film is formed.

Claims

1. A semiconductor device comprising:

an oxide semiconductor film over a substrate;

a pair of buffer layers on the oxide semiconductor film;

a pair of electrodes electrically connected to the oxide semiconductor film;

a gate insulating film over and in contact with a portion of a top surface of the oxide semiconductor film, a top surface of the pair of electrodes and a side surface of the pair of buffer layers; and

a gate electrode over the gate insulating film,

wherein each of the pair of buffer layers has a different taper angle between an inner side surface and an outer side surface, and

wherein the buffer layers comprise a metal oxide.

2. The semiconductor device according to claim 1, wherein a channel region included in the oxide semiconductor film has a hexagonal crystal structure.

3. The semiconductor device according to claim 1, further comprising an insulating film over and in contact with a top surface of the gate electrode and a portion of a top surface of the gate insulating film.

4. The semiconductor device according to claim 1, wherein the semiconductor device is one selected from the group consisting of a portable information terminal, a portable music player, a mobile phone and a television set.

5. The semiconductor device according to claim 1, wherein inner side surfaces of the pair of buffer layers have a larger taper angle than outer side surfaces of the pair of buffer layers.

6. The semiconductor device according to claim 1,

wherein the metal oxide is selected from the group of indium oxide, indium tin oxide, indium zinc oxide, tin oxide, zinc oxide, and tin zinc oxide.

7. The semiconductor device according to claim 6,

wherein the metal oxide further comprises one or more element selected from a group of aluminum, gallium, and silicon.

8. A semiconductor device comprising:

an oxide semiconductor film over a substrate;

a pair of buffer layers having n-type conductivity on the oxide semiconductor film;

a pair of electrodes electrically connected to the oxide semiconductor film;

a gate insulating film over and in contact with a portion of a top surface of the oxide semiconductor film, a top surface of the pair of electrodes and a side surface of the pair of buffer layers; and

a gate electrode over the gate insulating film,

wherein each of the pair of buffer layers has a different taper angle between an inner side surface and an outer side surface.

9. The semiconductor device according to claim 8, wherein a channel region included in the oxide semiconductor film has a hexagonal crystal structure.

10. The semiconductor device according to claim 8, further comprising an insulating film over and in contact with a top surface of the gate electrode and a portion of a top surface of the gate insulating film.

11. The semiconductor device according to claim 8, wherein the semiconductor device is one selected from the group consisting of a portable information terminal, a portable music player, a mobile phone and a television set.

12. The semiconductor device according to claim 8, wherein inner side surfaces of the pair of buffer layers have a larger taper angle than outer side surfaces of the pair of buffer layers.

13. The semiconductor device according to claim 8,

wherein the pair of buffer layers comprises a metal oxide, and

wherein the metal oxide is selected from the group of indium oxide, indium tin oxide, indium zinc oxide, tin oxide, zinc oxide, and tin zinc oxide.

14. The semiconductor device according to claim 13,

wherein the metal oxide further comprises one or more element selected from a group of aluminum, gallium, and silicon.