PV and IC industries converge
08/01/2008
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I had the good fortune to tour a solar cell manufacturing plant in East Germany earlier this year, and it was an eye-opening experience. I wouldn’t use the word “crude,” but it was a relatively simple operation, at least compared to an advanced IC manufacturing plant (or even a not-so-advanced one). Silicon was melted and cooled into large blocks (ingots), sawed into smaller blocks (bricks) with band saws, and then individual wafers were cut by wire saws.
This was followed by some cleanroom operations, including cleaning and etch, texture etch, diffusion, isolation, QC, etc., and then testing for efficiency. The plant I toured also included module manufacturing, where the cells were soldered, laminated, framed, and shipped.
This basic process is how most solar cells are manufactured today. What’s intriguing to me, however, are the thin-film solar cell processes where materials such as cadmium telluride (CdTe) or copper indium gallium diselenide (CIGS) are deposited on a glass or metal substrate. Tools for thin-film solar cell manufacturing tools are now available from Applied Materials, Oerlikon, and Ulvac (among others), largely based on know-how originally developed for manufacturing ICs and displays.
According to a new report from Lux Research, thin-film technology has now reached a critical mass and is poised to start taking “significant market share” from incumbent technology. Thin-film silicon technologies from turn-key vendors will be ramping up in large scale during the second half of 2008, while CdTe module producers such as First Solar—and new entrants Calyxo and Primestar—execute aggressive ramps. Meanwhile, CIGS module manufacturers are reaching the cusp of technology viability, with tremendous disruptive potential, according to the report.
“CdTe module manufacturing costs are less than one-third that of crystalline silicon, and the new amorphous silicon turn-key lines by Applied Materials and Oerlikon promise half the cost to start, with further declines in the future,” says Lux senior analyst Michael LoCascio. “These technologies will be the first choice for the burgeoning utility sector, squeezing out incumbent technology.”
Another recent report from iSuppli Corp. states that worldwide investments in the production of PV cells will rise to the same level as those for semiconductor manufacturing by 2010, due to booming demand for solar energy. Global production of PV cells is expected to rise to as much as 12 gigawatts (GW) by 2010, up from 3.5GW in 2007. By 2010, as many as 400 production lines in the world that can produce at least 1MW of PV cells per year will be in place, representing a fourfold increase from about 90 to 100 production lines in 2007. Factories capable of 1GW of annual PV production also will be established in the future to ensure continued strong delivery of PV cells to the market.
But no market can expand so quickly without some growing pains, particularly shortages that can impact supply. The global PV industry has the capacity to produce cells and modules that could generate far more electricity than can be supported by current supply levels for polysilicon. Production capacity limitations now are constraining polysilicon supply, the report notes.
“Polysilicon shortages are driving prices up,” said Dr. Henning Wicht, senior director and principal analyst, MEMS and PV, for iSuppli. “For companies attempting to expand their PV fabs to meet rising demand, it’s becoming very difficult to secure low-priced silicon.”
This is yet another reason why thin-film PV tech could come on strong. iSuppli notes that the silicon shortage also is driving the advancement of thin-film technologies that can act as the raw material for PV cells. Deposition of functional thin-film layers for PV cells can be conducted on glass, steel, or polymer foils, with no silicon wafers needed. Because of this, silicon cell manufacturers are investing in thin-film technologies in parallel with their expenditures on polysilicon.
This will cause the revenue market share of thin-film technologies to rise to 20% of the total PV market in 2010, up from 5% in 2007. Thin-film PV will grow by a CAGR of 70% from 2007 to 2010.
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Keep in mind, however, that the explosive growth in PV is fueled not so much by green fervor, but by government action. From national and regional subsidies and portfolio standards, to local zoning laws and homeowners’ association covenants, government regulations largely determine which markets grow, and how fast. That’s why this month’s cover story is devoted to covering the PV policy landscape. No matter how advanced the technology, government policy still rules when it comes to photovoltaics.