Large area transistors get helping hand from quantum effects

Aug 08, 2008

Researchers from the Hitachi Central Research Laboratory, Japan, and the Advanced Technology Institute of the University of Surrey today report that nano-designed transistors for the large area display and sensor application field benefit hugely from quantum size effects.

The unexpected superior switching performance (low leakage current, and steep sub-threshold slope) shown experimentally and analysed theoretically, demonstrate hitherto unexplored routes for improvements for transistors based on disordered silicon films.

By making the conduction channel in these disordered transistors very thin, the team has shown this technology will enable the design of low power memory for large area electronics based on a low-cost industry standard material processing route.

In the most recent investigations, the current of the devices, is found to be percolation governed when the channel is thinner than 3.0 nm due to strong quantum confinement induced potential variations over the active channel region. It is shown that the device channel width must be at least 0.3 µm to avoid percolative "pinch off" for 0.5 µm channel length devices. Theoretical analysis performed on the devices agrees well with the experimental data and provides important guidelines to model and optimize the devices for circuit design.

Dr Xiaojun Guo, one of the lead investigators, comments: "The nano-structure silicon thin-film transistors are very promising for design of low power electronics. However, carrier transport in such devices is very complicated, and results in electrical characteristics that may not be described by conventional field effect transistor (FET) models. This work reveals the key physical properties of the devices, which will help to further optimize and model the devices for circuit design".

Professor Ravi Silva, Director of the Advanced Technology Institute adds: "This study is a prime example of how leading silicon technologies entrenched in industry can find alternative routes to improve on performance in device characteristics by clever design. The role that funding organizations such as EPSRC play in supporting this type of applied research is invaluable to the community and most importantly to industry".

The results are published in Applied Physics Letters 93 (2008) 042105.

Reference: X. Guo, S.R.P. Silva, T. Ishii, "Current percolation in ultrathin channel nanocrystalline silicon transistors", Applied Physics Letters 93, (2008) 042105.

Provided by University of Surrey

Explore further: Toward making lithium-sulfur batteries a commercial reality for a bigger energy punch

add to favorites email to friend print save as pdf

Related Stories

Scientists explore mash-up of vacuum tube and MOSFET

Jun 25, 2014

Thumb-size vacuum tubes that amplified signals in radio and television sets in the first half of the 20th century might seem nothing like the metal-oxide semiconductor field-effect transistors (MOSFETs) that ...

Boosting microelectronics with a little liquid logic

Aug 08, 2014

Certain titanium-based metal oxides can form a crystal structure known as perovskite that results in a subtle internal imbalance of electric charges. This imbalance gives the material the ability to flip ...

Recommended for you

For electronics beyond silicon, a new contender emerges

Sep 16, 2014

Silicon has few serious competitors as the material of choice in the electronics industry. Yet transistors, the switchable valves that control the flow of electrons in a circuit, cannot simply keep shrinking ...

Making quantum dots glow brighter

Sep 16, 2014

Researchers from the University of Alabama in Huntsville and the University of Oklahoma have found a new way to control the properties of quantum dots, those tiny chunks of semiconductor material that glow ...

The future face of molecular electronics

Sep 16, 2014

The emerging field of molecular electronics could take our definition of portable to the next level, enabling the construction of tiny circuits from molecular components. In these highly efficient devices, ...

Study sheds new light on why batteries go bad

Sep 14, 2014

A comprehensive look at how tiny particles in a lithium ion battery electrode behave shows that rapid-charging the battery and using it to do high-power, rapidly draining work may not be as damaging as researchers ...

User comments : 0