In a first, scientists at the Indian Institute of Science (IISc.) have combined two different types of transistors — MOSFETs (Metal Oxide Semiconductor Field Effect Transistor) and tunnel FETs (Field Effect Transistor) — into a single device that can easily switch between power efficient and high performance modes, depending on the need.

The device has a special type of metal-semiconductor junction, which can be tweaked to make it behave either like a MOSFET or a tunnel FET.

The hybrid variety is an answer to issues that the most common MOSFETs have, that of being unable to bring down the supply voltage for MOSFETs proportionately with transistor size, because of a fundamental design flaw.

To overcome this, the tunnel FETs are being used. But they also have a disadvantage: the desired output — the current flowing when the transistor is on — is greatly reduced.

The hybrid device is capable of switching between MOSFET and tunnel FET modes using two gates instead of one, and a special type of electron barrier called Schottky junction. The Schottky barrier is created when a metal and semiconductor are joined under certain conditions.

According to a release, the dual-gated device was able to operate at a voltage lower than possible with conventional MOSFETs, greatly reducing power consumption. It also showed superior performance compared to current state-of-the-art tunnel FETs.

“You have flexibility,” says Shubhadeep Bhattacharjee, PhD student at the Centre for Nano Science and Engineering, IISc and first author of the paper published in Applied Physics Letters.

source: http://www.thehindu.com / The Hindu / Home> News> Cities> Bengaluru / by Staff Reporter / Bengaluru – December 21st, 2017