22-09-2008, 12:23 AM
The introduction of FinFET Technology has opened new chapters in Nano-technology. Simulations show that FinFET structure should be scalable down to 10 nm. Formation of ultra thin fin enables suppressed short channel effects.
It is an attractive successor to the single gate MOSFET by virtue of its superior electrostatic properties and comparative ease of manufacturability.
Since the fabrication of MOSFET, the minimum channel length has been shrinking continuously. The motivation behind this decrease has been an increasing interest in high speed devices and in very large scale integrated circuits.
The sustained scaling of conventional bulk device requires innovations to circumvent the barriers of fundamental physics constraining the conventional MOSFET device structure. The limits most often cited are control of the density and location of dopants providing high I on /I off ratio and finite subthreshold slope and quantum-mechanical tunneling of carriers through thin gate from drain to source and from drain to body.
The channel depletion width must scale with the channel length to contain the off-state leakage I off. This leads to high doping concentration, which degrade the carrier mobility and causes junction edge leakage due to tunneling. Furthermore, the dopant profile control, in terms of depth and steepness, becomes much more difficult.
The gate oxide thickness tox must also scale with the channel length to maintain gate control, proper threshold voltage VT and performance. The thinning of the gate dielectric results in gate tunneling leakage, degrading the circuit performance, power and noise margin.
