It's extremely difficult to raise venture capital funding for solar hardware companies, but somehow Siva Power just raised $25 million for its thin-film solar manufacturing think-tank/retirement project for thin-film technologists.

Siva closed this $25 million round to focus on building a pilot line and developing a solar module business -- with funding led by Jim Simons and Mark Heising, along with Jonathan Sheets.

Mark Heising is the managing director of Medley Partners. Jim Simons, a renowned mathematician, started the Medallion Fund, a wildly successful hedge fund. He's appeared on the Forbes top 100 richest people list and, until this investment at least, was called “the world’s smartest billionaire.”

Siva Power possesses an all-star team of thin-film solar technologists. This $25 million adds to the $15 million in financing from DBL Partners, Acero, Symmetry Group and Red House Capital that Siva closed in 2015 and the more than $60 million that Siva had raised in previous incarnations from Olympus Capital Partners, DBL Investors, Birchmere Ventures, Trident Capital and Firelake Capital.

Siva began in 2006 as Solexant, a cadmium-telluride (CdTe) solar on roll-to-roll startup, and was on the same build-a-factory-before-the-process-is-optimized death spin as the rest. But the board hired semiconductor equipment/process veteran and solar investor Brad Mattson in June 2011. Mattson was the CEO and founder of semiconductor equipment successes Mattson Technology and Novellus Systems.

At one point, the firm was investigating five materials systems. Solexant acquired the remains of Wakonda (GaAs), set world records in copper zinc tin sulfide, and forged ahead with CdTe.

In March 2013, Siva re-emerged from stealth with a new mission and a new name. Soon the company added CTO Markus Beck (who brought an extensive CIGS experience from his tenures with Solyndra and First Solar) and recently added former First Solar executive Bruce Sohn as CEO.

Mattson's ultimate technology conclusion was monolithically integrated, co-evaporated CIGS on glass, because it is "higher efficiency than anything else." (Not sputtering, not electroplating, not roll-to-roll, not foil, no singulation, no metal-organic chemical vapor deposition.) Mattson called co-evaporated CIGS one of those rare instances -- and a "gift of physics" -- where the highest-efficiency solution is also the fastest. Co-evaporation doesn't require the selenization step needed in a sputtering process.

At one point the company was looking to build "a profitable path to sub-$0.40-per-watt solar power, along with unprecedented production scale" until it had to update that number with the claim that it planned to build a 300-megawatt plant and eventually produce modules for 28 cents per watt.

The cost of silicon solar modules continues to drop. First Solar continues to improve its 2 gigawatts of thin-film module production capacity. First Solar’s lead-line module efficiency is approaching 17 percent.

Mattson sees the solar industry as being in the "gigawatt era" -- but the idea with thin film is to build that gigawatt in a 10,000-square-meter factory, not a 200,000-square-meter factory.

Hopefully, the engineering and investment community has learned something from the $4 billion to $5 billion invested in the CIGS solar material over the last decade. We've watched a number of copper-indium-gallium-diselenide solar companies raise funding and collapse with varying degrees of drama -- including Solyndra, Nanosolar, SoloPower and AQT.

Solar Frontier and MiaSolé are among the few firms still engaged in the production of CIGS thin-film technologies.

Mattson has told GTM in previous interviews: "Silicon scaled, but the Chinese are not scaling -- they are replicating like a cookie cutter. This is not scaling. China cannot compete with us if we scale properly."