SunEdison has begun production of polysilicon using its HP-FBR process at a plant in Ulsan, Korea through a joint venture with SunEdison Semiconductor and Samsung Fine Chemicals. The plant will supply Huntai Group with polysilicon for PV modules and projects, under a partnership announced in June.

FBR is a relatively new polysilicon process through which polysilicon is deposited when monosilane gas mixes with silicon seed particles in a reactor, in a continuous process. It is an alternative to the well-established but electricity-intensive Siemens method, which has been dominant in the polysilicon industry for decades.

FBR has several advantages, including lower cost due to a fraction of the electricity use of the Siemens process, but also requires less land and less capital per kilogram of product. SunEdison predicts that it can bring the cost of polysilicon down to US$0.05 per watt by 2016 using its FBR technology, which translates to under $10 per kilogram.

Several companies are exploring the use of FBR technology, including REC Silicon which has announced an 18,000 metric ton FBR expansion. Market analysts at IHS Technology have predicted that FBR will rise from its 10% market share in 2014 to a 17% market share in 2020.

Other FBR processes typically produce polysilicon at 6N-9N purities, which is lower than the 9N-11N which can be achieved with the Siemens process. However, SunEdison's new plant will produce 11N polysilicon using FBR. The company also says that the Ulsan plant's throughput is many times higher than other FBR makers.

The plant uses hydrogenation technology from GT Advanced Technologies for silane production and trichlorosilane to silane redistribution, but SunEdison has not revealed process details. GTM Research Lead Upstream Analyst Shyam Mehta says that all FBR makers are keeping quiet about their processes.

"Right now only REC, GCL and SunEdison are producing FBR, each using their own proprietary process," notes GTM Mehta. "So they are all quite different from each other, I believe, but there are no real details provided."