The Coherent FinFETProf. Carlo Requião da Cunha, Ph.D.

Chip in Rio Sep / 07

Laboratório de Circuitos Integrados UFSC

Núcleo Interdisciplinar de Microeletrônica

Ballistic TransportBallistic Transport

L < LL < Lmm (Momentum Relaxation Length) = (Momentum Relaxation Length) = .L.Lcc

Ballistic Transport

L

Lm

Diffusive Transport

*

2

m

ne = ?

Coherent TransportCoherent Transport

L < LL < L (Phase Relaxation Length) = (Phase Relaxation Length) = .L.Lcc

L

LL

Phase randomizing agents: e- - e-, e- - ph

A Model Device: Fin StructureA Model Device: Fin Structure

qEmwidth

fde2

22

636

1073.417.1

24

T

TEg

3

2ln

4

3

2Cde

dhBGF

Mm

mTkEEJ

Simulation StrategySimulation Strategy

Poisson Schrödinger

potential

density

0,,,2

2

yxEyxVyx

mde yxyx ,,

structure current

JUST MATH

Green’s FunctionsGreen’s Functions

011

102

01111 GGIG

VVG 022

02

1102221 GVGG

AN

RNNN GGTrT 1111

dEErrGrk

nk ;;

2

1

dEGGh

qI nout

drainpin

draindrain 2

Huge Discussion!Huge Discussion!

IIDD V VDS DS CharacteristicCharacteristic

Gating ActionGating Action

~73 A/V

Negative Gate BiasNegative Gate Bias

QuantizationQuantization

ConclusionsConclusions

• The coherent FinFET still retains some of the main properties of the classical MOS depletion transistor;

• Intrinsic quantum behavior makes the drain current marginally sensitive to gate action;

• Output resistance is highly reduced;

• The transistor shows a quantum transition for negative gate voltages that might lead to the design of new devices.