HP
Quantum Science Research
Ted Kamins - Materials Science & EE
Alex Bratkovski - Solid State Theory
Phil Kuekes - Computer Architecture
Yong Chen - Materials Science
Doug Ohlberg - Physical Chemistry
Tan Ha - Instrumentation
Xuema Li - Process Development
Duncan Stewart - Physics
Pavel Kornilovich - Theory
Shun-Chi Chang - Organic synthesis
Gun-Young Jung - Polymers & LB
Zhiyong Li - Electrochemistry & SAMs
Regina Ragan - Materials Science
Patricia Beck, Dick Baugh, Dick Henze
Sui-hing Leung, Sean Zhang, Kent Vincent,
Gana Ganapathian, Tom Anthony
UCLA
Prof. Fraser Stoddart - Organic Chemistry
Jan Jeppeson, Julie Perkins, H-R. Tseng
Prof. Jim Heath - Physical Chemisty
Pat Collier (Cal Tech), Yi Luo
Stanford
Prof. Curt Frank - Langmuir-Blodgett films
Isaac Lee
NIST
Curt Richter - Physics
Nanostructures
Switching
Computing
QUANTUM SCIENCE RESEARCH
(QSR)
• Fundamental physical limits for information
• Nanometer-scale structures
• self-assembly of dots and wires
• nano-imprint lithography
• Electronic switching
• theory and measurement of electron transport
• theory of ensemble transitions in solids and films
• Physics of Computing
• molecular-electronic integrated circuits
• defect-tolerant nano-circuit architectures
Theory and Modeling
Materials Growth
Physical Measurements
Chemical Fabrication
Circuit Architecture
Skill Sets
Instrumentation
HP Labs
Labs Centers
Centers
HP
HP Divisions
AS
QSR
Universities
National Labs
Corporate Labs
ITR
ENIAC - circa 1947
Shrink by 108
Improve power efficiency by 108
HP Jornada
Power cost of information transfer?
d 2
P = nkBT c n
cP
kBTd
n=
n
n= 1018 bit-ops/sec
nFor P = 1 Watt
nAbout 1 billion Pentiums
nin a hand-held device!
Research Areas Relevant
to ‘New-Era Electronics’
Molecular
Electronics
Spintronics
Single Electron
Devices
Quantum
Information
QSR Emphasis
and Partners
Molecular
Electronics
UCLA, CMU, NIST
ASD, STD, MTD
Quantum
Information
TESL, ITR
MIT, UNSW, Oxford
Goals of
Molecular
Electronics
Molecular Monolayer
Bottom electrode
SiO2
Si substrate
Top
electrode
Utilize quantum
behavior to build
useful devices e.g. a quantum state
switch
Develop techniques for
massively parallel
production of complex
systems from
nanoscale objects
e.g. quantum
circuitry
Two Challenges for Nanoelectronics
Invent a new switching device
Develop a new fabrication process
Examine Architecture First!
Reinvent the computer,
Not the transistor
HPL Teramac
1THz multi-architecture computer
• 106 gates operating
at 106 cycle/sec
• Largest defect-tolerant
computer
• Contains 256 effective
processors (FPGA’s)
• Computes with
look-up tables
• 220,000 (3%)
defective components
Teramac crossbar architecture
Address
lines
Lookup tables
Data
out
Memory
0
Switch
Data
lines
Teramac crossbar architecture
Address
lines
Lookup tables
Data
out
1
Memory
Switch
Data
lines
Nano-Circuit Architecture
Memory
0
Switch
Teramac crossbar
Cross-point Memory
US patents 6128214, 6256767, 6314019
demux
1
2
3
4
5
6
b
c
d
demux
a
e
Read
f
Out
Crosspoint programmable logic array
DEMUX
U
V
W
X
Y
Z
A
C
D
DEMUX
B
E
F
Y = (U AND V) OR (W AND X); Z = V+ C = VUS Patent # 6314019 & pending
Tunneling Gap
Barrier Height
Barrier Height
Tunneling Probability Depends
Exponentially on the
Barrier Width and Height
Tunneling Gap
Ideal Characteristics of an
Adjustable Tunnel-Barrier
Molecular Switch
1. Electrochemically accessible states
2. Molecular rearrangement
3. Reversible redox reactions
4. Processable
Cross Bar Chemical Assembly
Cross Bar Chemical Assembly
Cross Bar Chemical Assembly
Imprint Lithography
Mold
Polymer
Substrate
Yong Chen, Xeuma Li and Hylke Wiersma
and Gun-Young Jung
Imprint Lithography
Pt
SiO2
Ti/Pt
Y. Chen, G.Y. Jung et al.
DySi2 nanowires on a silicon (001) surface
Y.Chen et al. J.Appl.Phys. 91, 3213 (2002)
9 nm
1nm x 2nm
Langmuir-Blodgett Deposition
Device
Coupon
Microbalance
Barrier
Liquid Subphase
Langmuir Trough
Langmuir-Blodgett Deposition
Film molecule
Solvent molecule
Langmuir Trough
Langmuir-Blodgett Deposition
Film molecule
Solvent molecule
Langmuir Trough
Langmuir-Blodgett Deposition
Film molecule
Solvent molecule
Langmuir Trough
Langmuir-Blodgett Deposition
Langmuir Trough
Langmuir-Blodgett Deposition
Langmuir Trough
Isotherm
Pressure
Solid
phase
Liquid phase
Gas Phase
Area
Langmuir Trough
Device Characterization
Electrical characterization:
Current-Voltage I-V at 300K
Current-time pulse response
Physical characterization:
Electrodes by AFM
Film by Langmuir-Blodgett
conditions, AFM, contact angle
Device = Molecules + Electrodes
1-10 um
Top Electrode (Ti / Al)
Bottom Electrode (Al / Al2O3)
30 Å Al2O3
1-10 um
Top Electrode (Ti / Al)
Bottom Electrode (Pt)
5-30 Å
Monolayer molecular film
by Langmuir-Blodgett deposition
( Ti / Al )
Si
A [2]Pseudorotaxane...
[2]Pseudorotaxane
… A Dumbbell…
Dumbbell
...and...Three [2]Rotaxanes
Two-Station
Two-Station
Fast [2]Rotaxane Slow [2]Rotaxane
Single-Station
[2]Rotaxane
Eicosanoic acid control
Transport measurements
0
-40
-60
-80
-100
-3
-2
-1
0
Voltage (V)
1
2
3
Thread molecule (KAN241) control
Current (x0.1 nA)
0.4
0.3
0.2
0.1
-2
-1
0
Voltage (V)
1
2
2.5
Current (x10nA)
Rotaxane (KAN242) device
with poly-Si and Ti/Al electrodes Two different switching modes
Current (pA)
-20
2.0
1.5
1.0
0.5
0.0
-3
-2
-1
0
1
Voltage (V)
2
3
Work at UCLA (Heath and Stoddart Groups)
shows that Catenanes and Rotaxanes
exhibit molecule-specific electrical switching
when the bottom electrode is poly-Si
and the bias voltages are small (< 2V)
At larger bias voltages (~ 4V),
a completely different switching mechanism
with larger on/off ratio but less controllable
properties becomes dominant
Molecular catalogue
C
H3C
O
OH
C20H40O2
Eicosanoic Acid
O
OCH 3
HN
NH 2
H3CO
Fast Blue
Commercially available from catalogs
Chlorophyll B
Fast Blue, Eicosanoic Acid &
Control (Al bottom contact)
-9
-12
400x10
20x10
-12
800x10
15
300
Current (A)
600
10
200
3
5
400
100
0
1
200
-5
0
-100
-2
0
2
-1
0
1
2
Voltage (V)
3
4
HN
H CO
3
-2
-1
0
1
2
Voltage (V)
3
4
Eicosanoic Acid
Fast Blue
O
-10
-1.0
-0.5
0.0
0.5
Voltage (V)
1.0
Control - no film
OCH3
NH2
Duncan Stewart & Doug Ohlberg
Pulsed Behavior of Eicosanoic Acid Switch
Voltage (V)
4
3
2
1
0
-1
-2
Current (pA)
140
120
100
80
60
40
20
0
0
2
4
6
Time (s)
8
10
12
1-10 um
3 nm Al2O3
O
OC H3
Top Electrode (Ti / Al)
H CO
3
Current-Voltage
Fast Blue
NH
2
HN
Bottom Electrode (Al / Al2O3)
Remnance
400
300
Current (pA)
Current (pA)
100
200
3
100
1
0
-2
60
40
20
2
-100
80
-1
0
1
2
Voltage (V)
3
4
0
-2
-1
0
1
2
Set Voltage (V)
NDR and hysteresis (volatile switching)
3
Charge trapping model for
Al2O3/molecule dielectric bilayer
-ve charge accumulates
at interface, reducing
tunnel current flow
I
reverse bias
discharges interface
I
I
-
-
+ bias
1
large initial
tunneling current
- bias
+ bias
2
3
Aluminum electrode
observations:
– NDR and hysteresis at 300K
– 3 molecules with same electrodes, qualitatively
similar behavior
– Charge trapping model: affects tunnel current
transport
– Charging / discharging modulated by molecular film
– Generic mechanism for molecular devices
Low I
--+ bias
KAN 242 from Fraser Stoddart at UCLA
Pt electrodes
Current (mA)
10
5
0
-5
-10
-2.0
-1.0
0.0
Voltage (V)
1.0
KAN 242 on Pt
switch stress test
0.00
-0.10
-0.12
Current (A)
Current (A)
-0.05
-0.10
-0.14
-0.16
-0.15
-0.18
-3
-2
-1
0
Voltage (V)
1
2
-3
-2
-1
0
Voltage (V)
1
2
Can we build memory or logic ?
• MEMORY
– Use switching behavior in a crosspoint configuration
• LOGIC
– Diode logic: require open crosspoints and diode
crosspoints
• Do not yet have both
– Resistor logic: requires precise resistances
Resistor logic? Tunable resistor
R = 250 
Current (uA)
Current (mA)
10
5
0
-5
60
40
20
R = 25 k 
0
-10
-2.0
-1.0
0.0
Voltage (V)
1.0
0
20
40
60
80
Voltage (mV)
100
Resistor-resistor logic
A
RA
B
RB
1x3 array
A, B, C voltage inputs
‘Out’ voltage output
C
RC
Out
A
R
Out
B
2R
C
2R
Coupled logic gates:
( A AND B ) OR C
Reconfigurable !
( B AND C ) OR A
( A AND C ) OR B
KAN 242 on Pt : Logic circuit
demonstration
Voltage output (mV)
100
80
60
40
THRESHOLD
20
0
( A AND B ) OR C
( B AND C ) OR A ( A AND C ) OR B
Identical after 4 months
Conclusions
• DEVICE = MOLECULAR FILM + ELECTRODES
– Aluminum: NDR, Charge motion model, affects
tunnel current transport
– Platinum:
Switch with molecule or electrode reconfiguration
– Generic mechanisms in molecular devices
– USEFUL mechanisms: successful demonstration of
memory and logic
– Will these mechanisms scale to < 10nm ?
Hybrid Circuits of Silicon CMOS
and Molecular-Electronics
have the Potential
to Extend Moore’s First Law
for Another 50 Years