By Finlay Colville – Senior Analyst, Solarbuzz and Charles Annis – Vice President, Manufacturing Research, DisplaySearch
Israel-based Orbotech is well known in the FPD industry as the leading equipment supplier of TFT array test and automated optical inspection (AOI) equipment. And like many other leading FPD equipment companies, it has looked at the PV industry as a long-term diversification and growth opportunity. At its Investor and Analyst Day on June 8, Orbotech for the first time publicly unveiled its solar entry strategy.
In 2011, the company will launch a plasma enhanced chemical vapor deposition (PECVD) SiN antireflection (AR)/passivation deposition tool. Despite Orbotech’s high profile the product plans surprisingly have generated little press to date. But the story is quite interesting, and if successful, it offers a significant new revenue opportunity for the company.
SiN deposition tools play an essential role in every c-Si fab. SiN films, typically 70-80 nm thick, are deposited over the textured wafer using SiH4 + NH3 precursors in a PECVD system.
The SiN film matches the refractive indexes of air and silicon to reduce light loss from reflection. Furthermore, in the PECVD reaction hydrogen interacts with impurities and defects in the bulk silicon, which reduces electron recombination. PECVD-deposited SiN similarly also helps passivate the surface. Both the AR and passivation properties of SiN are critical parameters to achieve high conversion efficiency.
Orbotech did not provide any details on the tool configuration, but did suggest it will be an in line, high output machine offering low cost of ownership, and low power consumption.
Certainly, the SiN process requires proprietary technology. PECVD film quality varies substantially by machine design and process recipes. And the difficult challenge of trying to simultaneously control both AR and passivation properties within the film are probably why there are only a few competitors in this segment.
Orbotech will have its work cut out proving the technology to customers and making a name for itself in the solar equipment world. Otherwise, it seems like a great strategic move, because regardless which c-Si cell process flows are prominent in 2015, they will all need SiN (or similar) deposition tools. Solarbuzz forecasts the market for SiN deposition equipment will exceed $430M in 2010. And as solar cell manufacturers continue to emphasize high efficiency cell designs, passivation becomes even more important on both the front and back of the wafer that may translate to an even faster growing market in the future.
