SAN FRANCISCOA few years ago, while doing laser research for a PhD in applied physics at Harvard University, James Carey more or less accidentally discovered a new material which would come to be known as "black silicon."
The material, according to SiOnyx Inc., the company Carey co-founded to commercialize it, boasts more than 100 times the sensitivity of silicon, detects energy from the ultraviolet to the short-wave infrared bands, operates at a low voltage bias and, at less than 0.5 micron, is extremely thin.
Black silicon is also compatible with the existing CMOS process technology flow, making its fabrication easier and less expensive than more exotic, specialized materials that have been studied for some of the same applications, according to SiOnyx.
"This is a brand new material that is compatible with the largest manufacturing infrastructure in the world," said Stephen Saylor, SiOnyx president and CEO.
Black silicon forms the basis for shallow junction photonics, a patented semiconductor process that exploits atomic level alterations that occur in materials irradiated by high-intensity lasers. The process employs a femto-second laser that exposes the target semiconductor to high intensity pulses as short as one billionth of a millionth of a second.
Crystalline materials subject to these localized energy events undergo a transformative change, the atomic structure becomes instantaneously disordered and new compounds are "locked in" as the substrate re-crystallizes, according to SiOnyx. When applied to silicon, the result is a highly doped, optically opaque, shallow junction interface that is much more sensitive to light than conventional semiconductor materials, according to the company.
SiOnyx is initially targeting black silicon for silicon photodetectors for medical imaging and other applications. The company is also targeting imager applications for security, night vision, machine vision and digital still cameras, as well as applications for solar panels.
To date, SiOnyx has raised about $13 million, with Saylor acting as the largest investor. SiOnyx is currently meeting with venture capitalists to explore additional funding. Saylor said that, despite a dearth of financial capital that has driven some firms out of business, he believes the investment proposition offered by black silicon will be too attractive to pass up.
"We are very confident in our ability to raise investment, even in this environment," Saylor said. "When we tell our story to people who can understand the device physics involved, they are all over it."
Last month, SiOnyx added several image sensor scientists and engineers and opened an engineering office in Beaverton, Ore.