Researchers are conducting intense research into alternative technologies for replacing the current semiconductors used in today's electronics. The problem with current silicon is that the tech has a foreseeable end to the limits at which it can operate and the electronic world is constantly craving better performance.

Researchers at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California (UC) Berkeley have been working together on a project that has found an ultra-thin alternative to silicon that might find its way into future electronic devices. Rather than using silicon like today's semiconductors, the team was able to devise a method of transferring a better performing semiconductor material called indium arsenide onto a silicon substrate.

The researchers say that indium arsenide offers several key advantages when compared to silicon and is a member of the III-V class of semiconductors. This class of semiconductors has very fast and efficient electron transport properties, but the challenge has been finding a way to integrate the class of semiconductors with the established technology for constructing silicon-based devices today.

Research leader Ali Javey, a faculty scientist in Berkeley Lab’s Materials Sciences Division and a professor of electrical engineering and computer science at UC Berkeley, said, “We’ve shown a simple route for the heterogeneous integration of indium arsenide layers down to a thickness of 10 nanometers on silicon substrates. The devices we subsequently fabricated were shown to operate near the projected performance limits of III-V devices with minimal leakage current. Our devices also exhibited superior performance in terms of current density and transconductance as compared to silicon transistors of similar dimensions.”

The team of researchers has been able to transfer the ultra-thin layers of single-crystal indium arsenide onto silica/silicon substrates using a special method. The team grows the indium arsenide films that are 10 to 100nm thick on a preliminary source substrate and then lithographically patterns the films into ordered nano-ribbon arrays. Those arrays are then removed from the substrate using a selective wet-etching process and then stamped onto silicon substrates.

“We’ve demonstrated what we are calling an ‘XOI,’ or compound semiconductor-on-insulator technology platform, that is parallel to today’s ‘SOI,’ or silicon-on-insulator platform,” says Javey. “Using an epitaxial transfer method, we transferred ultra-thin layers of single-crystal indium- arsenide on silicon/silica substrates, then fabricated devices using conventional processing techniques in order to characterize the XOI material and device properties.”