Electronic circuit

• US 6,031,290 A
• Filed: 03/13/1998
• Issued: 02/29/2000
• 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:
  US09/041,702
• Time in Patent Office: 718 Days
• Field of Search: 257/344, 257/352, 257/383, 257/384, 257/408, 257/751, 257/763, 257/764, 257/354, 257/765
• US Class Current: 257/764
• 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. An electronic circuit comprising:

a semiconductor film having a thickness less than 1500 Å and

comprising silicon;

a source and drain provided in said semiconductor film;

a channel provided in said semiconductor film between said source and drain;

a gate electrode provided adjacent to said channel with a gate insulating film therebetween; and

an interconnect being in contact with at least one of said source and drain and comprising a first layer comprising titanium, a second layer comprising aluminum, and a third layer comprising titanium, said second layer being provided between said first layer and said third layer,

wherein said semiconductor film is in contact with said first layer at a region thereof which is provided in at least one of said source and drain and which contains therein an element selected from the group consisting of phosphorous, arsenic and boron at a concentration of 1×

10¹⁹ to 1×

10²¹ /cm³.

2. The circuit of claim 1 wherein nitrogen and titanium as constituents of said first layer are made to vary continuously.

3. The circuit of claim 1 wherein said semiconductor film has a sheet resistance less than 500 Ω

/square.

4. The circuit of claim 1 wherein said first layer has a thickness of 200 to 1000 Å

.

5. An electronic circuit comprising:

a semiconductor film having a thickness less than 1500 Å and

comprising silicon;

a source and drain provided in said semiconductor film;

a channel provided in said semiconductor film between said source and drain;

a gate electrode provided adjacent to said channel with a gate insulating film therebetween; and

an interconnect being in contact with at least one of said source and drain and comprising a first layer comprising titanium, a second layer comprising aluminum, and a third layer comprising titanium, said second layer being provided between said first layer and said third layer,

wherein said semiconductor film is in contact with said first layer at a region thereof which is provided in at least one of said source and drain and which contains therein an element selected from the group consisting of phosphorous, arsenic and boron at a concentration of 1×

10¹⁹ to 1×

10²¹ /cm³.

6. The circuit of claim 5 wherein said semiconductor film has a sheet resistance less than 500 Ω

/square.

7. The circuit of claim 5 wherein said first layer has a thickness of 200 to 1000 Å

.