U.S. solar equipment maker GT Solar International received a $228 million order from South Korea's OCI, sending its shares up as much as 9% to a more than 2-1/2-year high.

The announcement was the latest in a string of recent order announcements that have sent GT Solar's stock up 28% since April 25.
The order for polysilicon manufacturing equipment will be included in GT Solar's backlog for the quarter ending July 2, the company said in a statement on Wednesday.

Polysilicon is the key raw material in photovoltaic (PV) modules that turn sunlight into electricity. The solar industry is expected to begin adding polysilicon manufacturing capacity this year to support recent expansions of facilities that make solar panels. The equipment ordered from GT Solar will be incorporated into polysilicon producer OCI's new 20,000 metric ton Phase 4 production facility.

Merrimack, New Hampshire-based GT Solar, which also makes manufacturing equipment for the LED industry, has unveiled more than $710 million in orders since the end of April, according to Raymond James analyst Pavel Molchanov.

"We expect a huge backlog increase in the current quarter," Molchanov said in a client note. "The latest resumption in backlog growth should provide better insight for the rest of 2011 and into 2012."

GT Solar plans to report results for its fiscal fourth quarter on May 23.