Taking a closer look at Intevac’s production tool order, TSMC Solar’s CIGS efficiency record

  •   PHOTO OF PRODUCTION FLOOR COURTESY OF TSMC SOLAR
    PHOTO OF PRODUCTION FLOOR COURTESY OF TSMC SOLAR

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Tom Cheyney
Tom Cheyney
Tom Cheyney, former senior editor of PV-Tech and Photovoltaics International, is now chief curator of SolarCurator.com and director of Impress Labs’ solar practice.

The depressed state of the PV production equipment sector has been well chronicled. Few companies are adding or updating capacity, both on the crystalline silicon and thin-film PV fronts, and tool firms’ bookings (let alone billings) remain very light. Announcements of production orders are few and far between, so when a firm does score one, it should not go unnoticed/uncelebrated, no matter how modest.

Intevac’s recent news that it has secured an order for an ENERGi ion implant system from a “large Asian solar cell manufacturer” is notable for a few reasons. It marks the first time the Silicon Valley-based firm has won a production order for its implanter, although a handful of qualification tools have been deployed. The good thing about production orders is that a one-tool booking is rarely the end of the story and is usually followed by orders for more tools. From what I understand, you need a few implanters for every few hundred megawatts of cell production capacity.

Another noteworthy point about the report is that it means Intevac is making inroads in an area where Applied Materials’ Varian unit has dominated. Although the number of implanters installed on c-Si cellmaking lines is still relatively modest (a few score and ten or so), up until now the vast majority of the installed base has been Varian systems. I have heard from certain Varian customers that they would welcome more tool supplier choices for a variety of reasons, and were intrigued by Intevac’s (and Amtech/Kingstone’s) entry into the fray. Finally, the news suggests that some cellmakers are indeed actively upgrading their lines, understanding that the drive for lower costs coupled with higher efficiencies will require the insertion of production technologies like ion implantation that are extendable beyond the currently prevalent p-type doping schemes (POCl3 diffusion, your days are numbered) to the n-type generation cell architectures necessary to hit low-20% efficiencies and perhaps beyond.

One final note: the latest edition (18th) of Photovolatics International magazine has a very informative, exhaustively referenced technical article from Intevac technologists (downloadable here from the company website) (PDF) about the background, use, advantages, defect engineering, economics, and other aspects of c-Si solar cell ion implantation in general and specifically with Intevac’s “continuous flux ion-source” approach. One apparent double-benefit that cellmakers receive with the use of implanters is higher cell efficiencies and a narrower distribution of said efficiencies. In Intevac’s case, the company claims that an optimized tool running at 2400wph can improve absolute efficiencies by at least 0.5% over the incumbent process, which translates into an increase in manufacturing line output of more than 2MW/yr and a resulting monetary value said to be ~$1.4 million.

As remarked recently by SolarCurator, there has been a recent surge in the conversion efficiency competition among solar PV companies and research outfits. You can now add TSMC Solar to the titleholder pool. The CIGS thin-film PV unit of the 800-pound gorilla of the semiconductor foundry business has hit a record 15.1% on a handful of its monolithically integrated, commercial-sized modules, a number duly verified by TUV SUD and UL. This represents a nearly full percentage point increase since the company announced it had achieved 14.2% modules in September of last year.

Yes, they are champion modules, but it should be emphasized that the winning panels (there were more than one) were fabricated on the current manufacturing line in Taichung and not, as TSMC Solar’s Steve McKenery told me in a follow-up email, the result of “’slice-and-dice and reassembly of the best cells’ approach” used by some other players. “They are representative of what this tooling can produce,” he explains. Also keep in mind that that 15.1% is a total-area efficiency number, not the aperture-area figure that various folks use to pump up their stats (in some cases, the same ones who slice and dice). Steve notes that the efficiency record pushed those high-achieving modules’ power ratings up to 164W. When I interviewed company head YC Chao in early fall 2011 for PV-Tech, he said 30 x 30cm-sized R&D minimodule efficiencies were on the verge of hitting 15%, with the expectation that 17% would be achieved on the minis in 2012.

"We have been doing our R&D mainly on full-size modules for the last three quarters, so our 30 x 30cm mini-module efficiency record does not reflect our real champion capability,” TSMC Solar’s Marc Spaulding updated me in an email. “That said, in Q1'12 we were already at 17.5% 30 x 30cm efficiency. We [have] shifted most of our effort to the full-size module since Q1'12 exactly in order to bring the improvements in the 17.5% mini-module to commercial-sized modules. These 15.1% champion commercial-size modules are the result. Currently we have several significant efficiency improvements used in our 15.1% record modules that are waiting on certification to enter production. Those should be rolling out over the next several quarters, giving us a steady increase in shipping product wattage range on offer."

As one might expect in the current overcapacitized world, the TSMC line is running at less than full-tilt boogie, but McKenery says the team is “continuing to push hard on technology and process improvements to increase efficiency and reduce costs.” The company’s head of worldwide sales, who will soon be hitting the road for a certain emirate, adds that the company has “shipped product to Europe, U.S. and Asia, and are expanding our efforts into the MENA region as well.”

While some prognosticators see the post-shakeout thin-film PV sweepstakes narrowed down to two, maybe three prime-time contestants—First Solar, Solar Frontier, perhaps Hanergy—and some niche players, it would be unwise to discount the prospects of TSMC Solar, given their monster semiconductor manufacturing pedigree and the comparatively deep pockets of their parent. The Taichung crew is quietly tending to their optimization and cost-reduction knitting, securing channel partners, and patiently biding their time.

(The original version of this blog appeared on SolarCurator.com (http://www.solarcurator.com). Used with permission.)

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