This is an excerpt from EERE Network News, a weekly electronic newsletter.
Two Solar Cell Companies Cut Costs by Making More from Less
Two manufacturers of solar cells recently announced advancements that will yield lower-cost solar cells by squeezing more solar cell production out of existing equipment and materials.
Evergreen Solar, Inc. found a way to produce two ribbons of silicon simultaneously in one crystal-growth furnace, potentially doubling the company's production capacity. Evergreen Solar uses a proprietary process that avoids sawing silicon blocks, instead melting the silicon and drawing it out between two strings at high temperatures to form a ribbon between the strings. The company has already boosted productivity by making the ribbons 45 percent wider and increasing the growth rate by 40 percent. The company now hopes to introduce "double ribbon" production into its furnaces by late 2003. See the Evergreen Solar press release.
A different approach to the same problem is being pursued by Origin Energy, an Australian company, which is aiming to make inexpensive solar cells by using less silicon. The company apparently produces its new "Sliver Cell" by using micromachining technology, rather than saws, to slice extremely thin slivers of silicon from a block of silicon. The resulting product is flexible, translucent, and, according to the company, uses about one-thirtieth the amount of silicon used in standard crystalline-silicon solar cells. See the Origin Energy press release.
"Micromachining" usually refers to various methods of etching silicon and other materials to create extremely small structures. Such methods were recently used to produce a motor that could only be seen under a microscope. However, Oxford Lasers, Inc. uses the term to refer to laser cutting of silicon and other materials, a process that appears more applicable to the process of producing solar cells. See the Oxford Lasers fact sheet on laser micromachining of silicon (PDF 584 KB). Download Acrobat Reader.