Junction-Less nanowire transistor (JLNT) is a type of Field-effect transistor (FET) in which the channel consists of one or more nanowires and does not contain a junction.

Existing devices

Multiple JLNT devices were manufactured in various labs:

Tyndall National Institute in Ireland

JLT is a

nanowire file:SnSe@SWCNT.jpg, upright=1.2, Crystalline 2×2-atom tin selenide nanowire grown inside a single-wall carbon nanotube (tube diameter ≈1 nm). A nanowire is a nanostructure in the form of a wire with the diameter of the order of a nanometre ( ...

-based

transistor A transistor is a semiconductor device used to Electronic amplifier, amplify or electronic switch, switch electrical signals and electric power, power. It is one of the basic building blocks of modern electronics. It is composed of semicondu ...

that has no

gate A gate or gateway is a point of entry to or from a space enclosed by walls. The word is derived from Proto-Germanic language, Proto-Germanic ''*gatan'', meaning an opening or passageway. Synonyms include yett (which comes from the same root w ...

junction. (Even

MOSFET upright=1.3, Two power MOSFETs in amperes">A in the ''on'' state, dissipating up to about 100 watt">W and controlling a load of over 2000 W. A matchstick is pictured for scale. In electronics, the metal–oxide–semiconductor field- ...

has a gate junction, although its gate is electrically insulated from the controlled region.) Junctions are difficult to fabricate, and, because they are a significant source of current leakage, they waste significant power and heat. Eliminating them held the promise of cheaper and denser microchips. The JNT uses a simple nanowire of silicon surrounded by an electrically isolated "wedding ring" that acts to gate the flow of electrons through the wire. This method has been described as akin to squeezing a garden hose to gate the flow of water through the hose. The nanowire is heavily n-doped, making it an excellent conductor. Crucially the gate, comprising silicon, is heavily p-doped; and its presence depletes the underlying silicon nanowire thereby preventing carrier flow past the gate.

LAAS

A Junction-Less Vertical Nano-Wire FET (JLVNFET) manufacturing process was developed in Laboratory for Analysis and Architecture of Systems (LAAS).

Electrical Behaviour

Thus the device is turned off not by reverse bias voltage applied to the gate, as in the case of conventional

but by full depletion of the channel. This depletion is caused due to work-function difference ( Contact_potentials) between the gate material and doped silicon in the nanowire. The JNT uses bulk conduction instead of surface channel conduction. The current drive is controlled by doping concentration and not by gate capacitance. Germanium has been used instead of silicon nanowires.

References

Junctionless Nanowire Transistor: Properties and Device GuidelinesFerain Junctionless Transistors (pdf)
Transistor types Nanoelectronics {{Electronics-stub