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April 2-4, 2008
Photovoltaic Technology Show 2008 (continue..)
May 15-17, 2008
Solarexpo Exhibition (continue..)
September 1-5, 2008
23nd European Photovoltaic Solar Energy (continue..)
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DOPER
The machine consist in a chamber where a cloud of phosphoric acid is formed by mean of a special vaporizer unit.
A paper belt, used as carrier for wafers goes through the chamber where the phosphorus falling on top surface of wafer forming a thin film doper. Then the wafers are automatically transferred onto diffusion furnace where the temperature is around 900 C . This temperature force the P atoms drive in the silicon. Throughput is rated at > 2500 pcs/h of 6" wafers , based on its interfacing with a ceramics rollers furnace.
The paper belt permit the transportation of wafer into doper system and to the Doping furnace . Mass flow meter, thermocouples, and potentiometer get under control the parameter to keep constant and reliable the homogeneity of deposit, on the top surface of wafer.
Main advantages are:
- Very clean process, all the part in contact with the H3PO4 are fully inert with it and its vapor.
- Reliable process .
- Flux of each fluids are controlled and regulate from mass flux meters. Chamber of vaporizer controlled from P.I.D. All are reported at a supervisor computer.
- Possibility to mix DI Water at any ratio by an independent line.
- Economic process due at the economic doping source.
- Big capacity due at the easy and scalable process.
 Doper
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Doper (patent)
