MEMS for NEMSSolutions for the Fat Finger Problem

Michael Kraft

Overview

The Fat Finger ProblemManipulating AtomsManipulating IonsManipulating Larger ObjectsProbing Material at the NanoscaleConclusions

The Fat Finger Problem

Macroscopic tools are often unsuitable for nanoscale manipulationMEMS can provide a suitable solution There is only 1-2 orders of scale difference Nanofabrication can be integrated with MEMS fabrication

Richard E. Smalley, “Of chemistry, love, and nanobots,” Scientific American 285 (September 2001):76-77.

Integrated Micro-Chips for manipulation and trapping of atoms

Quantum lab-on-a-chip

Basic Research Quantum-behaviour Entanglement, coupling Low dimensional physics

Atom Chips

New devices – precise sensors Atom interferometer Atomic clocks Inertial sensors Quantum information processing Quantum computers

Gold Wires for Magnetic

Confinement of Atoms

Current through gold wires sets up a magnetic confinement field as a track for ultra cold atoms or atom cloudsFabrication process: Au-electroplating or ion beam millingEnables atom interferometry on a chip

Atom Interferometer on a Chip

23mm

Extremely high sensitivity for EM-fields, gravity

Micro-Cavities

KOH etched inverted pyramids surrounded by current Au-wires

Cavities: inverted pyramids or semi-spherical Magneto-optic cooling of atoms Optical resonators with high finesse for single atom detection

optic

al f

ibre

0.9999 bragg stack

dielectric coatedmicro-mirror0.9999

1 0 0 mm

RM

S R

ou

gh

ne

ss [

nm

] 0

5

0 20 40Etch duration [min]

Very smooth cavities

3D Electrostatic Actuator

s il ic o ns u b s t ra t e

g o ld w ire s

s il ic o ns u b s t ra t e

g la s ss u b s t ra t e

XY-motionAlignment of the optical cavity with fibreCorrection von bonding misalignment

Z-motionTunable optical cavity

Dis

tan

ce [

um

] 0

2

40 50 100 Voltage [V]

Nan0 Alignment Bonding

Demonstrated 200nm alignment bonding at chip level (2cm x 2cm)Only 10% of wafer area required for self-engaging structuresWafer surface smooth enough for thermo-compression bonding

self-engaging alignment conceptusing cantilevers

SEM image of aligned andbonded chips

Vernier structures to evaluate bonding alignment

IR image of a bonded sample

2.3mm

‘LEGO on a chip’

Integrated chips for manipulation and trapping of ions or charged particles

RF Paul Trap

Applications similar to Atom Chips(Semi-) Planar Paul TrapsCompatible with microfabrication technology

Ion Chips

Ion Traps With Shielded Dielectric

Field simulationY-Shaped Trap

SEM PictureWet etching 50/500nm Cr-Au DRIE 30um Si device layer

Overcome the problem of exposeddielectrics impeding the stability of trapRetain the simplicity of fabrication

The trap is well suited for trapping large array of single ions and perform quantum simulations2D ion trap arrays comprises of an RF metal above a grounded plane electrode

Ion 2D Lattice Trap

Micro-Particle Injection System für Laser Applications

Micro-particle injection for Laser chambers→ secondary radiation for medical applications, material testing, etcElectrostatic MEMS „rail gun“ (linear electrostatic motor)

Electro-magnetic Levitation• Electromagnetic Levitation System and Railgun

Bio-sensing Probe Application

Arthroscopic AFM sensor probe technology Cartilage health monitoring and analysisUses micro and nano-indentation approach to

characterise tissue stiffness [Ref: Stolz, et al., Nature Nanotechnology, 2009]

Ref: M. Stolz, J. Biophys., Vol 88, 2731-2740, 2010

Probes interaction with cartilage fibres using (A) micro-sphere probe tip and (B) nano sharp tip.

M. Stolz, Biophysical J., 98, 2010.

2 µm

Early Concept

and Prototype

Sharp AFM cantilever tip to improve indentation resolution (Tip radius 20nm -10nm)

Multiple probes for large area sensingRobust design to withstand operation stress Integrated readout with capacitance or

piezoresistance information

Self actuation AFM probe sensor design based on capacitive/piezoresistive readoutSEMs of AFM prototype device

fabricated on SOI material

Readout structures

Cantilevers

Probe tips

Cantilever length 500µm, 80µm & 3µm thick. Freq. = 40 kHz & k = 5.5 N/m.

Conclusions

MEMS can provide a toolkit for nanoscale manipulation of nano-sized objects.

These include trapping, detecting and shuffling of ions and atoms,

moving around small objects contactless,

and probing material, including biological tissue, at the nanoscale.

There are many other examples.

Thank you!