Semiconductor device having a lead including aluminum

• US 5,623,157 A
• Filed: 06/07/1995
• Issued: 04/22/1997
• Est. Priority Date: 12/09/1992
• Status: Expired due to Term

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Miyazaki, Minoru, Murakami, Akane, Cui, Baochun, Yamamoto, Mutsuo
• Primary Examiner(s): Ngo , Ngan V.
• Application Number:
  US08/483,049
• Time in Patent Office: 685 Days
• Field of Search: 257/352, 257/751, 257/763, 257/764, 257/765, 257/383, 257/384
• US Class Current: 257/383
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence
• CPC Class Codes: H01L 2224/45124 Aluminium (Al) as principal constituent
• CPC Class Codes: H01L 2224/48 of an individual wire connector
• CPC Class Codes: H01L 23/53223 Additional layers associated with aluminium layers, e.g. adhesion, barrier, cladding layers
• CPC Class Codes: H01L 27/12 the substrate being other than a semiconductor body, e.g. an insulating body
• CPC Class Codes: H01L 27/124 with a particular composition, shape or layout of the wiring layers specially adapted to the circuit arrangement, e.g. scanning lines in LCD pixel circuits wiring structures per se H01L23/52
• CPC Class Codes: H01L 29/458 for thin film silicon, e.g. source or drain electrode
• 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 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/10253 Silicon [Si]
• CPC Class Codes: H01L 2924/13091 Metal-Oxide-Semiconductor Field-Effect Transistor [MOSFET]

Abstract

An electronic circuit formed on an insulating substrate and having thin-film transistors (TFTs) comprising semiconductor layers. The thickness of the semiconductor layers is less than 1500 Å, e.g., between 100 and 750 Å. A first layer consisting mainly of titanium and nitrogen is formed on the semiconductor layer. A second layer consisting aluminum is formed on top of the first layer. The first and second layers are patterned into conductive interconnects. The bottom surface of the second layer is substantially totally in intimate contact with the first layer. The interconnects have good contacts with the semiconductor layer.

Claims

1. A semiconductor device comprising;

a semiconductor film having a thickness less than 1500 Å and

comprising silicon;

a first conductive layer in contact with said semiconductor film and comprising silicon and titanium;

a second conductive layer in contact with said first conductive layer and comprising titanium and nitrogen;

a third conductive layer in contact with said second conductive layer and comprising aluminum; and

a fourth conductive layer in contact with said third conductive layer and comprising titanium,

wherein said first, second, third, and fourth layers constitute a conductive lead.

2. The electronic circuit of claim 1 wherein said semiconductor film has N- or P-type conductivity.

3. The electronic circuit of claim 1 wherein said third layer has a thickness of 2000 to 5000 Å

.

4. The electronic circuit of claim 1 wherein said semiconductor film has a thickness between 100 and 750 Å

.

5. The electronic circuit of claim 1 further comprising a fourth layer located under said semiconductor film and in contact with said semiconductor film, and wherein said semiconductor film and said fourth layer are doped with a common impurity.

6. The electronic circuit of claim 1 wherein said conductive interconnect is connected with an external terminal.

7. A semiconductor device comprising:

a substrate;

a thin film transistor formed over said substrate;

a lead electrically connected to one of source or drain regions of said thin film transistor,

wherein said lead comprises a first conductive layer in direct contact with said one of source or drain regions of the transistor, a second conductive layer laminated on said first conductive layer, and a third conductive layer laminated on said second conductive layer, said first and third conductive layers comprising titanium and second conductive layer comprising aluminum, and said second layer being interposed between said first and third conductive layers.

8. A semiconductor device comprising:

a substrate;

a thin film transistor formed over said substrate;

an electrode comprising a conductive oxide material and operationally connected to said transistor through a lead, said lead having a laminar structure comprising at least a first conductive layer and a second conductive layer,

wherein said first conductive layer comprises titanium and directly contacts said electrode, and said second conductive layer comprises aluminum and is prevented from directly contacting said electrode by said first conductive layer interposed therebetween.

9. The semiconductor device of claim 8 wherein said first conductive layer directly contacts one of source or drain region of said thin film transistor.

10. The semiconductor device of claim 8 further comprising a third conductive layer comprising titanium, wherein said second conductive layer is interposed between said first and third conductive layers.

11. The semiconductor device of claim 8 wherein said conductive oxide material is selected from the group consisting of indium tin oxide and zinc oxide.