Applying TCZ's Thin Beam LTPS Processing Technology
The manufacture of advanced LCD and OLED displays is a complex process, and there are several types of poly-Silicon used in the display industry. One of the advantages of the TCZ system is that the system has the built-in capability to produce different types of poly-Silicon, so that the TCZ system can be used with the current manufacturing process as well as extended into future to support new process improvements. Using adjustments that can be commanded from the master controller, the TCZ system can be used to produce any of the three most common types of poly-Silicon:
This unique process versatility allows creating low temperature poly silicon material of different microstructure types, and therefore flexible optimization for various applications such as:
- Active matrix liquid crystal displays (AMLCD)
- System on glass integration (SOG)
- In-pixel memory and input display functionality (touch screen, scanner, etc.)
- Next generation organic light emitting diode (OLED) displays
ELA Material
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The most common form of poly-Silicon used in advanced display manufacturing is known as ELA material. It is composed of many small grains that grow in the vertical direction from the bottom of the film towards the top. While generally having a high degree of roughness, this film can be more uniform than others.
| • Microstructure: |
Random grains of 0.3 µm average size |
| • Electron mobility: |
≤100 cm2/Vs |
| • Surface Roughness: |
~tbd nm P-V |
| • Scan speed: |
50 cm2/s |
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SLS Material
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SLS material is used in some applications as it produces higher electron mobility than ELA. The crystallization process also has the highest throughput and largest process window, making it attractive for high volume manufacturing. The SLS material is mildly anisotropic, with different properties in the x and y direction.
| • Microstructure: |
Directional, 3-4 µm long grains |
| • Electron mobility: |
≤200 cm²/Vs |
| • Surface Roughness: |
~50 nm P-V |
| • Scan speed: |
~100 cm²/s |
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TDX Material
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TDX material has the highest electron mobility for applications such as embedded drivers or System-On-Glass. It also has very low surface roughness. The TDX material is highly anisotropic, so that the mobility is ~2x different in x and y directions.
| • Microstructure: |
Directional, >10 µm long grains |
| • Electron mobility: |
Up to 350 cm²/Vs |
| • Surface Roughness: |
≤10 nm P-V, ±3 nm RMS |
| • Scan speed: |
~70 cm2/s |
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