Semiconductor device with modified mobility and thin film transistor having the same

• US 7,479,667 B2
• Filed: 12/28/2004
• Issued: 01/20/2009
• Est. Priority Date: 12/30/2003
• Status: Expired due to Fees

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kwon, Jang-yeon, Park, Young-soo, Noguchi, Takashi, Kim, Do-young
• Primary Examiner(s): Lewis; Monica
• Application Number:
  US11/022,756
• Publication Number:
  US 20050139923A1
• Time in Patent Office: 1,484 Days
• Field of Search: 257/52, 257/55, 257/63, 257/64, 257/53, 257/221, 257/344, 257/335, 257/336, 257/404, 257/548, 257/550, 257/213
• US Class Current: 257/213
• CPC Class Codes: H01L 21/02381 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/02488 Insulating materials
• CPC Class Codes: H01L 21/02532 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/02678 Beam shaping, e.g. using a mask
• CPC Class Codes: H01L 21/02686 Pulsed laser beam
• CPC Class Codes: H01L 27/1285 using control of the annealing or irradiation parameters, e.g. using different scanning direction or intensity for different transistors
• CPC Class Codes: H01L 27/1296 adapted to increase the uniformity of device parameters
• 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 29/1029 of field-effect transistors
• CPC Class Codes: H01L 29/6675 Amorphous silicon or polysilicon transistors
• CPC Class Codes: H01L 29/78663 Amorphous silicon transistors
• CPC Class Codes: H01L 29/78672 Polycrystalline or microcrystalline silicon transistor
• 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

Provided are a semiconductor device including an active area which is defined as high and low mobility areas and a thin film transistor having the semiconductor device. The mobility of the active area can be lowered to a level enough to satisfy the requirement of the semiconductor device. The lowering of the mobility of the active area can contribute to reducing mobility deviation between semiconductor devices. As a result, the quality of a flat panel display adopting a large-scale semiconductor device can be greatly improved.

Claims

1. A thin film transistor comprising:

a Si-based channel having an active area including at least two high mobility areas and at least one low mobility area along an electron mobility path of a thin film transistor, the two high mobility areas being separated by the low mobility area along the electron mobility path of the Si-based channel;

a source and a drain which are respectively formed on sides of the Si-based channel along the electron mobility path;

a gate for applying an electric field to the Si-based channel; and

an insulating layer interposed between the active area and the gate,

wherein said Si-based channel includes more than two high mobility areas and a plurality of low mobility areas.

2. The thin film transistor of claim 1, wherein the low mobility area is formed in the center of the high mobility areas.

3. The thin film transistor of claim 1, wherein the high mobility areas have a polycrystalline structure, and the low mobility area has an amorphous structure.

4. The thin film transistor of claim 1, wherein the high mobility areas have a polycrystalline structure, and the low mobility area has a micro polycrystalline structure.

5. The thin film transistor of claim 1, wherein the high mobility areas are formed of SiGe, and the low mobility area has a single crystalline structure.

6. The thin film transistor of claim 1, wherein the high mobility areas have a micro polycrystalline structure, and the low mobility area has an amorphous structure.

7. The thin film transistor of claim 1, wherein the high mobility areas have a substantially same thickness as the low mobility area in a direction normal to the electron mobility path.