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Transcript of Resonant_tunneling-Laresgoiti slides.pdf
Izaro LaresgoitiLow dimensional systems
Quantum tunnelingResonant tunneling RTD
StructureHow does it work?Materials
ApplicationsConclusions
α decay:Polonium -212 (alpha particle 8,78MeV)
LkC eT 22−∝
0.287eV
0.0807eV
0.287eV0.0807eV
χ21sin4)1( 22
LRRL
RL
RRRR
TTT+−
=
RLka ρρχ ++= 2
nπχ 2=
22 )(4
)1( RL
RL
LR
RLPK TT
TTRR
TTTT+
≈−
==
The condition for resonant states!
Assuming that TL and TR are small:
Near the resonance (TL and TR<<1)12
211)(
−
⎥⎥⎥⎥
⎦
⎤
⎢⎢⎢⎢
⎣
⎡
⎟⎟⎟⎟
⎠
⎞
⎜⎜⎜⎜
⎝
⎛
Γ
−+= pk
pk
EETET Breit-Wigner
1 2 3 4ã
0.2
0.4
0.6
0.8
1
T€€€€€€€€€€Tpk
Γ
Er
Scape rate
TL=TR=0.8
TL=TR=0.2
Regions (12-25nm)I-V: Emitter/collector(heavily doped(~108cm-3)
small bandgap, GaAs)II-IV: Q barrier(~0.23eV):larger bangap
(AlGaAs).III : QW: smaller bandgap
I
IIIIIIV
V
Important performance parameter:1.Peak current density (Jp)2.Valley current density (Jv)3.Peak to valley ratio (PVR): Jp/Jv
NDR
jp
jv
1. E1: Resonant energy2. E2: phonon
absorption3. E3: phonon emission 4. E4:Thermoionic
emission5. Non resonant
tunneling
Valley current
To obtain the better performance1. Maximize Ip
high frequency (>104
A/cm 2)
2. Minimize Ivreduce lekege current and hence the power consumtion.
3. Maximize PVR allow an
appropriate memory with a reasonable noise margin
4. Minimize RCt
NDR
Real current curve
To increase Ip: (increases f)1. Decrease the
thickness of the barrier
2. Increase the doping in the emitters
However:Increases also the IVDecreases the PVR
Trade off between high speed and power consumption!!
Small device (12-25nm/conventional device
~100nm)
Extremely high switching speed (e.g., 1 ps
switch, fmax~1 THz/215GHz conventional)
Low power consumption
Work at room temperature
Flexible design
NDR characteristics(Intrinsic bistability ,
incfrease functionality)
Type III-V (Eg. GaAs, InP)Good PVR and current density Ip~500kA/cm2
PVR ~52Good for high frequency switching applicationsCMOS incompatible and high cost
Si basedCMOS compatibleRTD Not good properties (NDR at low temp, PVR ~1.2-2.4)RITD
RITD type III-VRITD based in Si
Compatible with CMOSNDR at room TPVR~4Ip~2kA/cm2
Microwave oscillatorsNDR compensate the R
Ideal oscillator
Real oscillator
RTD avoid the amplitude decay
Novel digital logic circuits.(PVR=10 enough)Static memory (computer)
RTD more stable (NDR), bistability.Reduced the number of devices
The simplest configuration
Due to the continuous development of computer industry is inevitable the use of quantum based devices because they provide:
Low footprint and high device density.High switching speed(high computation capacity)Low power consumption
Due to their high switching velocity and the NDR RTDs are very useful for very high frequency oscillator circuits.
Books:
“The Physics and Applications of Resonant Tunnelling Diodes”. by Hiroshi Mizuta, Tomonori Tanoue. (Cambridge Studies in Semiconductor Physics and Microelectronic Engineering).
“Nanoelectronics and Information Technology: Advanced Electronic Materials and Novel Devices” by Rainer Waser
“The Physics of Low-dimensional Semiconductors: An Introduction” by John H. Davies
Papers and talks:
L.L. Chang, L. Esaki, and R. Tsu. “Resonant tunneling in semiconductor double barriers”, Appl. Phys. Lett. 24, 593 (1974).
S.L. Rommel, T.E. Dillon, M.W. Dashiell, H. Feng, J. Kolodzey, P.R. Berger, P.E. Thompson, K.D. Hobart, R. Lake, A.C. Seabaugh, G. Klimeck, and D.K. Blanks, “Room Temperature Operation of Epitaxially Grown Si/Si0.5Ge0.5/Si Resonant Interband Tunneling Diodes “, Appl. Phy. Lett, 73, 2191 (1998).
“Resonant Tunneling Diodes: Theory of Operation and Applications”. Johnny Ling, University of Rochester, Rochester , NY 14627
“Brief overview of nanoelectronic devices”, James C. Ellenbogen. Government Microelectronics Applications Conference (GOMAC98).
“Resonant Tunneling Transistor Characteristics Using a Fabry-Pariot Resonator”. Chomsik Lee. Journ. Korean Physic. Soc, vol 31
“Long journey into tunneling”. Leo Esaki. Nobel Lecture, December 12, 1973
“Confined Electrons and Photons. New Physics and Application”. Elias Burstein and Claude weisbuch
“Extending CMOS: Quantum functional Circuits Using Si-Based Resonant Interband Tunneling Diodes”. Paul R. Berger. March 11, 2005
“Resonant Tunneling Diodes”. Ni, Man. Advanced Electronic Devices. April 26. 2005
“ Quantum Wells, Wires, Dots; Quantum Coherent Devices”, Stephen Goodnick. IEEE Nanotechnology Conference in 2003
nanoHUB: online simulations and more: https://www.nanohub.org/tools/rtd/ (Simulate 1D resonant tunneling devices and other heterostructures via ballistic quantum transport)