Scalable Ion Traps with Monolithically Integrated CMOS Controls

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Scalable Ion Traps with Monolithically Integrated
CMOS Controls

• Dick Slusher
• Rae McLellan
• CS Pai
• Bell Laboratories
• Lucent Technologies

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Wonderful People

• Lucent
• Dick Slusher (ion trap design, testing)
• CS Pai (fabrication) New Jersey NanoConsortium
  fabrication team
• John Gates (fabrication)
• Yee Low (packaging)
• Dave Ramsey (packaging)
• Bob Frahm (packaging)
• Rae McLellan (electronics and system design)
• MIT
• Dave Leibrandt (design, simulation, testing)
• Ike Chuang (overall design, architectures)
• NIST (now at Ulm)
• Rainer Reichle
• Ion groups
• NIST
• University of Michigan

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Alfred Lord Tennyson

• ---- maybe wildest dreams
• are but the needful preludes of the truth

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Any intelligent fool can make things bigger, more
complex, and more violent. It takes a touch of
genius -- and a lot of courage -- to move in the
opposite direction. Albert Einstein
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Present Ion Traps
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Non-scaling Ion Trap
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Scalable Ion Trap Quantum ComputerSystem Design
Measurement
Ion traps
MEMS Optics
Ion/Optics Control Electronics
Classical Computer
System Compatibility of Quantum and
Classical Spatial Pitch Clock Speed Operating
Temperature Power Dissipation
SIMD (Single Instruction on Multiple
Data) Single gate laser - Multiple ion
gates Single cooling laser Multiple ion
traps Single DAC Multiple ion traps
Great for Ions!
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Linear Trap with Through Wafer Access
RF electrode spacing 150, 125, 100, 75 mm (center
to center)
University of Innsbruck Oxford
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NIST Quantum CCD Planar Trap Design
Trap axis
Field lines
Cross-section view
Top view
Dave Kielpinski Chris Monroe John Chaiverini Dave
Wineland
rf electrodes
ac electrodes
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Scalable Ion Trap Quantum Computer Vision
System Compatibility of Quantum Classical
Spatial Pitch, Clock Speed Operating Temperature,
Power Dissipation
Kim, et. al., QIC (2005)
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Planar Ion TrapScalable Silicon VLSI
RF Electrodes 1mm Thick W/Al 20 mm Wide
p doped Si wafer 0.018 Wcm 6W
CRF/CC 100
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Electric Fields Above VLSI Planar Ion Trap
Height (mm)
Position (mm)
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Trap Loading Problems?
VRF 100V Cd Electrode Separation 85 mm RF
frequency W/2p 50MHz Trap frequency wsec /2p
3 MHz Stability parameter q 221/2 wsec/W
0.17
290K
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Split control electrodes for doppler cooling
V1
V2
-V
V
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Sources of Johnson noise heating in planar traps

• Control circuit resistance Rc 20 ?
• CMOS transmission gates, 10 ?
• Wiring, 10 ?

?RF
?c
CRF
Rc
Johnson noise in RF drive (heats ions via
parametric process)
Cc
Control electrode sheet resistance ?c/tc 0.03
?/?
RF electrode sheet resistance ?RF/tRF 0.03 ?/?
v
D. Leibrandt, B. Yurke and R. E. Slusher, to be
pub. QIC
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Ion Heating
Present Trap Data Anomolous heating 1/d4
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First generation control electrode layout
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New control electrode layout

• Eliminating split between RF electrodes reduces z
  Johnson noise heating by a factor of 5
• Cooling and micro-motion control

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VLSI Planar Traps
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(No Transcript)
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Recess etch of Oxide Below RF Rail
RF rail
Etched oxide
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RF Drive
Capacitance 4.6 pf Loss tangent 0.0025

• Limit RF voltage 400 V peak
• (in air)
• 300 V (in vacuum)
• No Outgassing or resnance shift

Al ground plane Q 360 No Al ground plane Q 150
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First Ion
111Cd 06/23/06 Dan Stick Monroe
Group University of Michigan
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Linear Trap with Loading Slot
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Micro-motion

• Ions not located at the node of the RF electric
  field exhibit driven motion at the RF frequency,
  called micro-motion

Time averaged total pseudo-potential
RF
DC
?x
RF frequency
cooling less efficient quantum logic operations
slower
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Micro-motion control
y
z

X (mm)
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Planar Cross Problem
x 0
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Cross Planar Trap
Rainers Rule d control d ion
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Present RF Cross
Control electrodes
Ion Height (mm)
Trapping Depth (V)
RF electrode
Transport Dimension (mm)
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Revised X Trap
100 mm
1 mm
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Future Designs
R. Reichle
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Goal 1000 traps/cm2
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Ion trap layout Bacon/Shor Quantum Error
Correction Turing model

• Simplest layout ancilla 9 qubits in line

data ion
ancilla ion
Ike Chuang
First operation put in 0011
state same with
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• Simplest layout ancilla 9 qubits in line

data ion
ancilla ion
First operation put in 0011
state same with
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• Simplest layout ancilla 9 qubits in line

data ion
ancilla ion
First operation put in 0011
state same with
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• Simplest layout ancilla 9 qubits in line

data ion
ancilla ion
First operation put in 0011
state same with
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• Simplest layout ancilla 9 qubits in line

data ion
ancilla ion
Second operation verify ancilla by comparing
and
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• Simplest layout ancilla 9 qubits in line

data ion
ancilla ion
Second operation verify ancilla by comparing
and
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Evolution Path
Digital Analog Voltage (DAC) source
Dramatic reduction in interconnect density with
vertical Interconnects and CMOS electronics
1000 ion/cm2
Vacuum seal
FSM
CMOS Transmission gate switch
CMOS Logic
Monolithic integration allowed by low T trap
fabrication
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Initial Estimates
Gate Density Xs, Ts and Loading zones Ion density 1000/cm2
1 CNOT with Steane 7 qubit code Two
Concatenations
150 mm
Chip edge connections 2000 very
difficult Wiring cross talk Wiring
complexity (islands)
50 mm
Control electrodes
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Transmission Gate
Inverter
Control
n-FET
DAC Voltage In
DAC Voltage Out
p-FET
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CMOS

• 0.18 mm rules
• Electrode voltage limit 1.8 V
• OK for 50 mm control electrode/ion distances

• p and n mobilities and FET dimensions limit
  resistance
• R a L/mW

• 6 metalization layers
• 2 for transmission gates
• 4 for DAC voltage interconnects

• A bargain _at_ 425k/wafer

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Waveforms
Control Electrode
Off Chip DACs
Tgates
Vo
High
V1
Low
V2
Sin
V3
Cos
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Serial In
Serial Out
2b Shift Register
Clock
2
2-4 Decoder
4b latch
Latch
V0
V2
V1
V3
Control Electrode
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Sequence
1 msec
V2
Serial In
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4 to 1 Analog Tgate Multiplexor with Serial
Control Logic
Control Electrode Outline 50x50 mm2
Connection to electrode layer
4 p-FETs
4 n-FETs
RC 5W
Inverters
54m x 42m
Shift Register, Decoder and Latch
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Summary

• Planar traps work!
• Monolithic integration of trap and controls
• SIMD (Single Instruction on Multiple Data)
• Single gate laser - Multiple ion gates
• Single cooling laser Multiple ion traps
• Single DAC Multiple ion traps
• CMOS Electronics control designs
• Applications in Reach (100 1000 ions)
• Quantum repeaters
• Quantum simulation
• Worries
• Immediate concerns
• High pressure
• Control electrode lifetimes
• Charging effects