Mar 15 2010
Prof. Roger W. Whatmore, CEO of Tyndall National Institute, University College Cork, is in Silicon Valley this week, participating in a Trade and Investment Mission led by Ireland's Prime Minister, Brian Cowen. The Mission was organized by Enterprise Ireland, the Irish state agency responsible for the development and promotion of Ireland's indigenous business sector. Prof. Whatmore will present information on a recent technology breakthrough achieved by Tyndall-the world's first junctionless transistor-a development that could revolutionize semiconductor microchip manufacturing and help ensure the continuation of Moore's Law well into the future.
This technology breakthrough is the result of research funded by Science Foundation Ireland and conducted by a team of scientists at Tyndall led by Professor Jean-Pierre Colinge. They designed and fabricated a junctionless transistor that significantly reduces power consumption and greatly simplifies the IC manufacturing process. Currently, all existing transistors are based upon junctions, which are formed when two pieces of silicon with different polarities are placed side by side. 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. It is also a major factor in the cost and complexity of semiconductor production.
Tyndall's groundbreaking technology eliminates the need for a junction. Instead, the current flows in a very thin silicon wire and is perfectly controlled by a "wedding ring" structure that electrically squeezes the silicon wire in the same way that the flow of water through a hose can be controlled by squeezing the hose. These new structures are easy to fabricate, even at extremely small design nodes, thereby offering a significant potential to reduce manufacturing costs.
As design nodes shrink, minimizing current leakage has become a significant challenge. The Tyndall junctionless devices have near ideal electrical properties and behave like the most perfect transistors, thereby alleviating this challenge. In addition, they have the potential to operate at greater speeds and consume less energy than the conventional transistors used in today's microprocessors.
In other developments, researchers at Tyndall are exploring the use of alternative semiconductor materials formed from the elements in group 3 and 5 of the periodic table. These elements, known as III-Vs, have superior properties to silicon and offer the possibility of building microchips with superior performance and greater energy efficiency than those produced today.
Fabricating fully operational III-V transistors will require combining III-V semiconductors with insulators of only a few atomic layers in thickness. To improve device performance, these insulating layers must have a high dielectric (high-k) constant. One of the major challenges in fabricating III-V transistors is the ability to control the properties of the interface between the III-V semiconductor and the high-k layers. Researchers at Tyndall, led by Dr. Paul Hurley, have recently developed a new process that results in a fourfold improvement in the electronic properties of this critical high-k/III-V interface that will reduce the voltage required to turn the transistor on and off.