But the technology is winning more converts because cells can be made much more cheaply, on sheets of high-grade glass and using much thinner layers of the costlier materials that give them their energy-generating properties.

"I think the growth rate of thin film might be double or more than that of crystal silicon," said Charles Gay, general manager of the solar business group for Applied Materials.

"The efficiencies are climbing for the thin films. They haven't been around as long and we're still in the learning phase," Gay told Reuters in an interview.

Applied Materials, the world's biggest supplier of tools for making microchips, doesn't make solar cells itself, but sells the equipment that is used to make them.

The basic technology is the same as that used to make LCD televisions, a business Applied got into years ago with the dawn of the notebook computer.

Today, concern over high oil prices, energy security and global warming is mounting, and Applied realized the same equipment that can crank out 52" flat-panel televisions can also be used to produce vast amounts of solar cells.

At AKT, Applied's flat-panel display and solar cell tool subsidiary, technicians work away on a typical tool -- a 15-foot-high (5-meter-high) stainless steel chamber that is so large it takes more than one jumbo jet to ship it.

"In the past, you burned something to get energy, and now you make something and what you make can produce energy," Gay said.

Applied's Chief Executive Mike Splinter has relentlessly promoted the company's solar message, saying the company aims to sell US$500 million in solar equipment by 2010.

That may not be much for a company that did US$9.2 billion in revenue last year, but it is a growth area for company whose main customers -- microchip makers -- are seeing demand for their products slow to the high single digits.

Applied has a simple formula for calculating its potential solar market.

Gay figures the solar industry will add about 7,500 megawatts of generating capacity in 2010, while installing enough equipment to expand total capacity by about 2,000 megawatts.

It costs roughly US$1.50 per watt to add capacity, so the total market for equipment to make solar cells will be around US$3 billion in 2010.

Applied's US$500 million target means its share of the solar equipment market will be about 17 percent.