3D silicon wafers boost photovoltaic cell production
1366 Technologies in Massachusetts has developed a process called Direct Wafer that allows a thin silicon wafer with a thick border to be grown, which is not possible with conventional ingot-based production technologies.
While sawing a silicon ingot with diamond wires can produce wafers thinner than the standard 180-200 µm thickness, these thin wafers have reduced mechanical integrity and can break during cell fabrication, electrical interconnection and encapsulation in modules. This means wafer thickness has remained at 180 to 200 µm. The ability to selectively grow a waafer means the standard 180-200 µm thickness can be provided in stress-critical areas such as wafer perimeter or ribs where busbar soldering will occur, while reducing thickness to between 100 to 120 µm for the remainder of the wafer. The result cuts silicon consumption to ~1.5 g/W and creates a strong, thin wafer able to withstand typical manufacturing stresses, and the process makes wafers in a single step, pulling them directly from molten silicon instead of today’s multi-step process. The lower silicon consumption and simpler process give significant wafer production cost savings, says the company, as well as allowing new 3D wafer features that reduce cost and increase efficiency.
The company was founded in 2008 and in June signed a deal with Wacker Chemie in Germany for polysilicon. Wacker is also investing $15 million in 1366 as an extension of the Company’s Series C financing for the working capital necessary for its plant plant and in prepayment of 1366’s initial silicon needs.
1366 plans to produce millions of wafers a year at the Science and Technology Advanced Manufacturing Park (STAMP) in Genesee County, New York, supporting power generation of 250 MW. The factory will eventually grow to more than 3 GW, house 400 Direct Wafer furnaces and employing 1,000 people.