Junctionless transistor could simplify chip making, say researchers

LONDON — In a move that could revolutionize nanoelectronics manufacturing and the semiconductor industry, scientists at the Tyndall National Institute (Cork, Ireland) have designed and fabricated what they claim is the world's first junctionless transistor.

The breakthrough is based on the deployment of a control gate around a silicon wire that measures just a few dozen atoms across. The gate can be used to "squeeze" the electron channel to nothing without the use of junctions.

Professor Jean-Pierre Colinge Tyndall National Institute

The junctionless transistor, otherwise known as the gated resistor, which could simplify manufacturing of transistors at around the 10-nanometer stage, was created a by a team led by Professor Jean-Pierre Colinge (shown left) and a paper on the development has been published in Nature Nanotechnology.

The structure simplifies the production of transistors and also produces a near-ideal sub-threshold slope, extremely low leakage currents and less degradation of mobility with gate voltage and temperature than classical transistors, the researchers have claimed. Nonetheless such device can be made to have CMOS compatibility.

Since their invention transistor- and diode-action has depended on controlling the flow of electrons across junctions giving rise to the familiar NPN and PNP notation for bipolar devices and p- and n-type FETs with sources and drains. Controlling the junction allows the current in the device to be turned on and off and it is the precise fabrication of this junction that determines the characteristics and quality of the transistor and is a major factor in the cost of production. However, as a consequence of the repeated miniaturization predicted by Moore's Law transistors at the leading edge are becoming so small that conventional transistor architectures are becoming exceedingly difficult to fabricate.

"We have designed and fabricated the world s first junctionless transistor that significantly reduces power consumption and greatly simplifies the fabrication process of silicon chips," declared Tyndall's Professor Colinge, in a statement.

Cross section of a silicon wire with wrap-around insulator and overlaid gate