THIN FILM TRANSISTOR AND MANUFACTURING METHOD THEREOF

• US 20130175521A1
• Filed: 05/23/2011
• Published: 07/11/2013
• Est. Priority Date: 06/01/2010
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Moriguchi, Masao, Takei, Michiko, Kanzaki, Yohsuke, Inoue, Tsuyoshi, Fukaya, Tetsuo, Takanishi, Yudai, Nakatani, Yoshiki, Nakanishi, Kenji, Kusumi, Takatsugu, Okamoto, Tetsuya
• Granted Patent: US 8,779,478 B2
• Time in Patent Office: Days
• US Class Current: 257/43
• CPC Class Codes: H01L 29/24 including, apart from doping materials or other impurities, only semiconductor materials not provided for in groups H01L29/16, H01L29/18, H01L29/20, H01L29/22 including organic materials H10K99/00
• CPC Class Codes: H01L 29/66742 Thin film unipolar transistors
• 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 29/78618 characterised by the drain or the source properties, e.g. the doping structure, the composition, the sectional shape or the contact structure silicide contacts, electrodes in general H01L29/458
• 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

Abstract

A TFT 20 includes a gate electrode 21, a gate insulating film 22, a semiconductor layer 23, a source electrode 24, a drain electrode 25, etc. The semiconductor layer 23 is comprised of a metal oxide semiconductor (IGZO), and has a source portion 23a that contacts the source electrode 24, a drain electrode 23b that contacts the drain electrode 25, and a channel portion 23c that is located between the source and drain portions 23a, 23b. A reduced region 30 is formed at least in the channel portion 23c of the semiconductor layer 23, and the reduced region 30 has a higher content of a simple substance of a metal such as In than the remaining portion of the semiconductor layer 23.

Claims

1. A thin film transistor provided on a substrate, comprising:

a gate electrode;

a gate insulating film covered by the gate electrode;

a semiconductor layer placed to face the gate electrode with the gate insulating film interposed therebetween;

a source electrode connected to the semiconductor layer; and

a drain electrode separated from the source electrode and connected to the semiconductor layer, wherein the semiconductor layer is comprised of a metal oxide semiconductor including an oxide of at least one of In, Ga, or Zn, and has a source portion that contacts the source electrode, a drain electrode that contacts the drain electrode, and a channel portion that is located between the source and drain portions,

a reduced region is formed at least in the channel portion of the semiconductor layer, and the reduced region has a higher content of a simple substance of In than a remaining portion of the semiconductor layer, and

the reduced region extends substantially in the entire channel portion.

2-7. -7. (canceled)

8. A thin film transistor provided on a substrate, comprising:

a gate electrode;

a gate insulating film covered by the gate electrode;

a semiconductor layer placed to face the gate electrode with the gate insulating film interposed therebetween;

a source electrode connected to the semiconductor layer; and

a drain electrode separated from the source electrode and connected to the semiconductor layer, wherein

the semiconductor layer is comprised of a metal oxide semiconductor including an oxide of at least one of In, Ga, or Zn, and has a source portion that contacts the source electrode, a drain electrode that contacts the drain electrode, and a channel portion that is located between the source and drain portions,

a reduced region is formed at least in the channel portion of the semiconductor layer, and the reduced region has a higher content of a simple substance of In than a remaining portion of the semiconductor layer, and

the reduced region is provided in the channel portion, and is present substantially only in a surface region thereof located on an opposite side from the gate electrode in a thickness direction of the channel portion.

9. The thin film transistor of claim 8, wherein

the reduced region extends in surface regions of the source portion and the drain portion continuously from the channel portion.

10. The thin film transistor of claim 8, wherein

the content of the simple substance of In in the reduced region is in a range of 3 to 100%.

11-15. -15. (canceled)