ULVAC PE-CVD system increases conversion efficiency by 30 percent

TOKYO, JAPAN: ULVAC Inc., a supplier of the amorphous-silicon (a-Si) thin-film photovoltaic modules production turnkey line, has developed a new PE-CVD system for microcrystal (µc)-Si, model CIM-1400, which can achieve a 30 percent increase of the conversion efficiency and a 10 percent reduction of the manufacturing cost per watt (Wp) compared with the a-Si photovoltaic modules.

This new system will be utilized to the tandem type thin-film silicon photovoltaic modules production turnkey line.

Though the a-Si thin-film photovoltaic modules are made from silicon, an abundant and secure material resource, even they use only a small amount of silicon: that is, one hundredth or less of the crystalline silicon photovoltaic cells.

For this reason, a-Si thin-film photovoltaic modules have received widespread attention as a product that will become the mainstream of photovoltaic cell in the future, and are being developed all over the world.

However, since a-Si thin-film photovoltaic modules have a lower photoelectric conversion efficiency than crystalline photovoltaic modules, efforts have been made to develop the technologies and manufacturing equipment for tandem type thin-film photovoltaic modules, which have a µc-Si layer added to an a-Si thin-film solar cell (a-Si layer). So far, however, no practicable and productive technologies for manufacturing equipment have been developed until today.

In this situation, ULVAC has developed a new PE-CVD system for µc-Si, model CIM-1400. This system for the first time, allows productive high efficient µc-Si film formation, which can allow light from the red to infrared wavelengths to be converted to electricity.

By incorporating this new CIM-1400 PE-CVD system to the production turnkey line for tandem type thin-film silicon photovoltaic modules, power output will be improved by 30 percent or more compared to a-Si thin-film PV modules.

The following lists the features of the new PE-CVD system “CIM-1400”, and “CIM-1400” utilized tandem type thin-film silicon photovoltaic modules production turnkey line.

For this system, a Generation 5.5 size glass substrate, a common glass substrate for thin-film silicon photovoltaic modules, is used.

High productivity for high-performance tandem type thin-film silicon PV modules
The performances of tandem type thin-film silicon photovoltaic modules produced by “CIM-1400” utilized tandem type thin-film Production turnkey line is:
• Cell conversion efficiency: 9% (in the aperture area)
• Average module power output: 130Wp (annual productivity: 32.5 MW)

Innovative PE-CVD system for microcrystals
To produce high-performance thin-film silicon photovoltaic modules, the silicon thin films needs to be formed at a low deposition rate. In addition, to form µc-Si thin films with high conversion efficiency, a thicker film is required compare to the a-Si thin film. Therefore, theoretically large quantities of PE-CVD systems have been required.

ULVAC's highly innovative breakthrough new PE-CVD system “CIM-1400” enables to process six glass substrates at the same time, achieving high productivity at a low deposition rate and this tandem type thin film silicon photovoltaic modules Production turnkey line is operated with a throughput every 90 seconds per substrate.

Manufacturing cost per watt (Wp) reduced by up to 10 percent compared with a-Si thin-film photovoltaic modules
This breakthrough enables the annual productivity (power output) of the modules to be increased from 25 MW (a-Si thin film photovoltaic modules) to 32.5 MW (tandem type photovoltaic modules) maximizing the investment productivity more than the investment cost required for the PE-CVD system “CIM-1400”.

The new innovative PE-CVD system “CIM-1400” and the tandem type photovoltaic modules production turnkey line has successfully reduced the manufacturing cost per watt for the first time in the world, by replacing the a-Si thin-film photovoltaic modules with the tandem type thin-film photovoltaic modules.

The PE-CVD system “CIM-1400” and tandem type photovoltaic modules production turnkey line will be released on July 1, 2009.