US5555112A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Liquid crystal display device having multilayer gate busline composed of metal oxide and semiconductor
Assignee: Hitachi Ltd
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Filing: 1994-02-09
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Granted: 1996-09-10
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Expires: 2014-02-09
Abstract
Abstract In a liquid crystal display substrate in which the pixel electrode is applied with a voltage through the drain and source of a thin-film transistor (TFT) that conducts by a voltage applied to the TFT gate electrode, this gate electrode and a busline connected to the gate electrode are formed as a multi-layered structure consisting of a gate layer and at least two layers of a gate insulation film and an amorphous silicon film. The multi-layered structure is formed by etching through a single mask.
Inventors
- 👤 Ryoji Oritsuki
- 👤 Minoru Hiroshima
- 👤 Masahiro Yanai
- 👤 Masaaki Matsuda
- 👤 Toshikazu Horii
- 👤 Yuichi Hashimoto
- 👤 Hayao Kozai
- 👤 Kenkichi Suzuki
- 👤 Masaru Takabatake
- 👤 Takashi Isoda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 14:27
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/136; G02F1/1362; G02F1/136286; H; H10; H10D; H10D86/00; H10D86/40; G02F1/13629; Y; Y10; Y10S; Y10S148/00; Y10S148/105
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
135 words
A liquid crystal display substrate comprising: pixel electrodes; thin-film transistors, each having a gate electrode, a drain and a source, the gate electrode being applied with a voltage to impress a voltage on the associated pixel electrode through the drain and source of the thin-film transistor, each thin-film transistor having a gate insulating film overlying the gate electrode, a silicon layer on the gate insulating film, and a highly doped silicon film on the silicon layer, sides of the gate electrode not being covered by the gate insulating film such that the sides are exposed thereby, and an insulating layer, different from the gate insulating film, covering the sides of the gate electrode and not covering a top of the gate electrode; and interconnect layers or buslines connected to gate electrodes of the thin-film transistors.
Claim 2
Dependent Claim
135 words
A liquid crystal display substrate comprising: pixel electrodes; thin-film transistors, each having a gate electrode, a drain and a source, the gate electrode being applied with a voltage to impress a voltage on the associated pixel electrode through the drain and source of the thin-film transistor, each thin-film transistor having a gate insulating film overlying the gate electrode, a silicon layer on the gate insulating film, and a highly doped silicon film on the silicon layer, sides of the gate electrode not being covered by the gate insulating film such that the sides are exposed thereby, and an insulating layer, different from the gate insulating film, covering the sides of the gate electrode and not covering a top of the gate electrode; and interconnect layers or buslines connected to gate electrodes of the thin-film transistors.
Claim 3
Dependent Claim
27 words
A liquid crystal display substrate according to claim 1, wherein the insulating layer is a layer formed by an anodic conversion of material of the gate electrode.
Claim 4
Dependent Claim
37 words
A liquid crystal display substrate according to claim 1, wherein the gate electrode is made of at least one layer made of a material selected from the group consisting of aluminum, tantalum and titanium and their alloys.
Claim 5
Dependent Claim
20 words
A liquid crystal display substrate according to claim 1, wherein the insulating layer is made of an organic insulating material.
Claim 6
Dependent Claim
24 words
A liquid crystal display substrate according to claim 1, wherein said gate electrode and said gate insulating film have a same shape and dimensions.
Claim 7
Dependent Claim
26 words
A liquid crystal display substrate according to claim 5, wherein said silicon layer and said highly doped silicon film also have said same shape and dimensions.
Claim 8
Dependent Claim
21 words
A liquid crystal display substrate according to claim 1, wherein the interconnect layers or buslines are extensions of said gate electrodes.
Claim 9
Dependent Claim
32 words
A liquid crystal display substrate according to claim 1, wherein the gate electrode, gate insulating film, silicon layer and highly doped silicon film all have a pattern formed using a same mask.
Claim 10
Dependent Claim
37 words
A liquid crystal display substrate according to claim 1, wherein the gate electrode is made of a material selected from the group consisting of aluminum, aluminum and silicon, tantalum, titanium, copper, palladium, tantalum nitride and titanium nitride.
Claim 11
Dependent Claim
20 words
A liquid crystal display substrate according to claim 1, further comprising a chromium layer overlying the highly doped silicon film.
Claim 12
Dependent Claim
48 words
A liquid crystal display substrate according to claim 1, wherein the insulating layer includes a first sub-layer which is formed by an anodic conversion of material of the gate electrode, and a second sub-layer on the first sub-layer, the second sub-layer being made of an organic insulating material.
Claim 13
Dependent Claim
150 words
A process for fabrication of thin film transistors in active matrix liquid crystal display devices, comprising the steps of: disposing a gate layer on an insulation substrate; disposing a gate insulation layer over said gate layer; disposing a silicon layer over said gate insulation layer; disposing a contact layer, comprising a highly doped silicon layer, over said silicon layer; patterning said contact layer, silicon layer, gate insulation layer and gate layer with a same etching mask to form gate electrodes of said thin film transistors, side surfaces of said gate electrodes being exposed; disposing a side insulation layer to cover the exposed side surfaces of the gate electrodes; disposing a source and drain conductive layer over said contact layer and said substrate; and patterning said source and drain conductive layer and said contact layer so as to form a source electrode and a drain electrode of said thin film transistors.
Claim 14
Dependent Claim
150 words
A process for fabrication of thin film transistors in active matrix liquid crystal display devices, comprising the steps of: disposing a gate layer on an insulation substrate; disposing a gate insulation layer over said gate layer; disposing a silicon layer over said gate insulation layer; disposing a contact layer, comprising a highly doped silicon layer, over said silicon layer; patterning said contact layer, silicon layer, gate insulation layer and gate layer with a same etching mask to form gate electrodes of said thin film transistors, side surfaces of said gate electrodes being exposed; disposing a side insulation layer to cover the exposed side surfaces of the gate electrodes; disposing a source and drain conductive layer over said contact layer and said substrate; and patterning said source and drain conductive layer and said contact layer so as to form a source electrode and a drain electrode of said thin film transistors.
Claim 15
Dependent Claim
36 words
The fabrication process of claim 12, wherein said gate layer is made of a material selected from the group consisting of aluminum, aluminum and silicon, tantalum, titanium, copper, palladium, nitride of tantalum and nitride of titanium.
Claim 16
Dependent Claim
20 words
The fabrication process of claim 13, wherein said side insulation layer comprises an oxide of material of said gate layer.
Claim 17
Dependent Claim
29 words
The fabrication process of claim 13, wherein said side insulation layer is formed by anodic conversion of a portion of said gate layer, exposed from said gate insulation layer.
Claim 18
Dependent Claim
8 words
Product formed by the process of claim 15.
Claim 19
Dependent Claim
16 words
The fabrication process of claim 12, wherein said side insulation layer comprises an organic insulation agent.
Claim 20
Dependent Claim
8 words
Product formed by the process of claim 17.
Claim 21
Dependent Claim
8 words
Product formed by the process of claim 12.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-09-10 | 2000-03-11 | 2000-09-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-09-10 | 2004-03-11 | 2004-09-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-09-10 | 2008-03-11 | 2008-09-10 | $7700.00 | Window Closed / Lapsed |