Active matrix substrate and liquid crystal device

• US 8,659,713 B2
• Filed: 01/13/2011
• Issued: 02/25/2014
• Est. Priority Date: 06/02/2010
• Status: Active Grant

• Current Assignee: Trivale Technologies, LLC (Vector Capital Corporation)
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: Takeguchi, Toru, Tanina, Osamu
• Primary Examiner(s): KIM, RICHARD H
• Application Number:
  US13/005,781
• Publication Number:
  US 20110299005A1
• Time in Patent Office: 1,139 Days
• Field of Search: None
• US Class Current: 349/43
• CPC Class Codes: G02F 1/1362 Active matrix addressed cells G02F1/134336, G02F1/134363 take precedence
• CPC Class Codes: G02F 1/136209 Light shielding layers, e.g. black matrix, incorporated in the active matrix substrate, e.g. structurally associated with the switching element
• CPC Class Codes: H01L 27/1255 integrated with passive devices, e.g. auxiliary capacitors
• 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 29/78633 with a light shield
• 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

In an active matrix substrate, the source electrode side and/or the drain electrode side of a crystalline semiconductor film extends to an area located outside both the thin-film transistor and the gate electrode, and a metal light-shielding film is provided, in the same layer as the gate electrode, between the contacting portion between the source electrode or the source line and the crystalline semiconductor film and the gate electrode, and/or between the contacting portion between the drain electrode and the crystalline semiconductor film and the gate electrode. An impurity-implanted region implanted with n-type impurity may be formed between the contacting portion between the source electrode or the source line and the crystalline semiconductor film and the gate electrode, and/or between the contacting portion between the drain electrode and the crystalline semiconductor film and the gate electrode.

Claims

1. An active matrix substrate comprising a plurality of pairs of an inverted staggered type thin-film transistor and a pixel electrode arranged in array, the inverted staggered thin-film type transistor comprising a gate electrode and a gate insulating film sequentially formed on an insulative substrate, a channel layer comprising a crystalline semiconductor film and an amorphous semiconductor film sequentially formed on the gate insulating film, and a source electrode and a drain electrode formed on the channel layer with a space therebetween, wherein

a source electrode side and/or a drain electrode side of the crystalline semiconductor film extends to an area located outside both the thin-film transistor and the gate electrode,

the active matrix substrate further comprises a metal light-shielding film formed, in a same layer as the gate electrode, between a contacting portion between the source electrode or a source line connected to the source electrode and the crystalline semiconductor film and the gate electrode and between a contacting portion between the drain electrode and the crystalline semiconductor film and the gate electrode, and

the metal light-shielding film is not formed in extended portions which are located outside the contacting portions in a direction of the source line and the metal light-shielding film does not block light in the extended portions.

2. The active matrix substrate according to claim 1, wherein a the metal light-shielding film is configured to receive an externally applied positive voltage.

3. The active matrix substrate according to claim 2, wherein the positive voltage is higher than a threshold voltage of the thin-film transistor.

4. The active matrix substrate according to claim 2, wherein the metal light-shielding film constitutes a wiring line configured to receive an externally applied positive voltage.

5. The active matrix substrate according to claim 2, wherein the metal light-shielding film is electrically connected to the source line, and a positive voltage can be thereby externally applied to the metal light-shielding film through the source line.

6. A liquid crystal device comprising a liquid crystal panel comprising an active matrix substrate according to claim 1, an opposed substrate, and a liquid crystal layer sandwiched between these two substrates.

7. The liquid crystal device according to claim 6, further comprising a backlight, wherein the liquid crystal device is a transmission type liquid crystal device.