When it comes to fashion—and solar cells—thin is in. In fact, the thinner the solar cell, the less it costs to produce, and the more competitive the sales price will be on the global market.
To date, Twin (News - Alert) Creeks, a Silicon Valley-based startup that develops manufacturing equipment for solar modules, sensors, LEDs and other solid-state devices, has been working clandestinely to come up with a way to produce super-skinny crystalline wafers, which are less than one-tenth as thick as their conventional counterparts. Twin Creeks’ Hyperion manufacturing process is churning out wafers at half the cost of comparable wafers already on the market.
That’s a huge breakthrough: The precipitous plunge in price could enable the U.S. solar industry to sell solar energy as a practical alternative to fossil fuels. A solar-factory based around Hyperion can produce cells for less than $0.40 a watt, or almost half of the price of current systems.
The Hyperion process uses a technique called Proton-Induced Exfoliation (PIE) to embed high-energy protons (or hydrogen ions) into “donor” wafers — standard wafers of silicon, germanium, or other single-crystal materials— where they form a uniform layer beneath the surface of the donor. The physical attributes of hydrogen, combined with the conditions created by Hyperion, allow the ions to penetrate the surface of the donor wafer without changing its inherent properties and characteristics.
When heated, the ions exfoliate a uniform, ultra-thin layer called a lamina from the donor wafer. The lamina becomes a production wafer, and can be processed into thin solar cells or semiconductor devices.
Twin Creeks uses an analogy to describe the way the process works: The ions act like a scalpel and carve thin, identical and functional wafers from the donor. A single donor wafer can be reused repeatedly to create multiple laminae. Twin Creeks has lifted 14 laminae from a single donor wafer in its labs with Hyperion and produced solar cells on ten laminae lifted from a single donor wafer.
While the ultra-thin wafers produced with Hyperion contain only a fraction of the material required for a standard wafer, the solar cells, LEDs or devices produced from the Hyperion lamina provide similar or better levels of performance as devices made from conventional “fat” wafers. In fact, Hyperion has the potential to produce single-crystal wafer facilities that are up to 90 percent more efficient and reduce demand for other wafer manufacturing equipment.
More, higher-performing devices are thus made with far less material. Below, Twin Creeks' 20-micrometer-thick metal-coated silicon wafers are flexible and strong (source: Twin Creeks).
Though others have experimented with producing thin wafers, Hyperion is the only production-ready system that can produce thin lamina in volume today. The system works because it operates at high voltage and high current, an unusual combination. High voltages are essential for deeply embedding ions, while high current is important for the high throughput needed in modern manufacturing.
A single Hyperion 3 system, Twin Creeks’ commercial-scale manufacturing tool, can process over 1.5 million thin wafers per year, enough for over 6 megawatts’ worth of solar cells. While Twin Creeks will initially concentrate on silicon wafers, Hyperion can be employed to produce thin crystalline wafers made from gallium arsenide, germanium and other materials.
In partnership with the U.S. State of Mississippi, Twin Creeks currently is building a state-of-the-art wafer and solar cell facility in Senatobia, Mississippi. Senatobia will be used as a living laboratory by Twin Creeks and its customers to optimize manufacturing and production processes for Hyperion and Hyperion-based manufacturing lines. Customers will be able to experiment with production processes, which they can subsequently deploy in their own factories, with assurance that their trade secrets and techniques will not be shared with other clientele. The facility, once fully operational, will be capable of producing 100 megawatts of solar modules a year.
Twin Creeks also has an existing agreement with the Perak State Development Corporation, Malaysia to develop a 500MW solar module production facility using its proprietary Hyperion technology. The site, located in the Perak High Tech Park in Ipoh, Malaysia (about 125 miles north of Kuala Lumpur) is under development and available for customer partnerships.
According to Technology Review, Twin Creeks does not plan to make its own solar panels. Instead, the company hopes to sell its Hyperion manufacturing system to solar panel makers. Twin Creeks says its Hyperion technology can be easily incorporated into already-existing solar factories.
So far, Twin Creeks has raised $93 million in venture capital, and has also received a loan from the state of Mississippi to build its factory. Now that the secret is out, it’s liable to create headlines in the solar industry in a hurry.
Edited by Braden Becker