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Nanomechanics - Nano Electro Mechanical Systems

Danny Porath 2002

Links to NEMShttp://www.nano.physik.uni-muenchen.de/index.htmlhttp://www.its.caltech.edu/%7Enano/research.html

http://www.zfm.ethz.ch/e/res/mic/http://www.aip.org/web2/aiphome/pt/vol-54/iss-10/p38.html

http://www.mems-exchange.org/http://www.intel.com/research/silicon/mems.htm

.....

ReviewsMicroelectromechanical Systems: Technology and Applications" MRS Bull. 26 (April 2001).See Homework

Based on Works of…….

1. Yossi Shacham-Diamand – TAU

2. Young-Ho Cho - KAIST

3. Michael Roukes – Caltech

4. Valluri Rao - Intel

5. Scientific American September 2001

Outline:1. General issues (links, homework etc.)

2. Introduction

3. The technology

4. Examples

5. Summary

Homework 121. Read the paper:

“Nanoelectromechanical Systems”, By: H.G. CraigheadScience 290, 1532 (2000).

2. Read the paper:“Nanoelectromechanical systems face the future”, By: Michael Roukes,

Physics World 14(2), February 2000. 3. Read the paper:

“Measurement of the quantum of thermal conductance”, By: K. Schwab, E.A. Henriksen, J.M. Worlock & M. L. Roukes

Nature 404, 974 (2000).

The Miniaturization Trend

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Miniaturization TrendGeneral Approach

Develop micron scale disciplines: Mechanical, biological, chemical

integrate them on a chip with microelectronics

Build “a system on a chip”

Keep miniaturizing it

NeedsDriving Forces

Electro-Mechanical SystemsMEMS Technology (mid 80’s-)

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MEMS TechnologyMiniaturization Technology

Fundamental ResearchHistorical Review I

Historical Review IITop-Down Evolution of Micro-System Technologies

Semiconductor microelectronics, (1960 -),

~200B$ (@2000), ~140B$ (2001)

Micro-Electro-Mechanical Systems (1985 - )

µElectro-OptoMechanical Systems (1980 - )

µ-Bio-

µ-Chemical

(1995 - )

Micro-System-Technology (MST) - System on a chip - Integrated electronics, MEMS, µBio, µChemistry & µElectro-optics

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The key for the future of micro-technologiesDevelop micron scale disciplines:Mechanical, biological, chemical and integrate them on a chip with microelectronics

SOCs will be scaled down according to Moor’s law

Integrated systems will still require micron size patterns

Microsystems will be the base for nano technologies - platforms, packages, SOCs

On-Chip Multi System IntegrationImproved performance: higher speed, lower power

Smaller volume and/or area: portability, accessibility and convenience

Lower cost - saving packaging and number of components

Higher reliability - less connection, less components count

Simpler design - design large arrays of the same units

Lower parasitic capacitance, inductance

Ability to handle small volume of liquids, reagents

Ability to handle small biological units.

Key DirectionsResearch in basic technologies, materials and solid state phenomena

Interdisciplinary research - Micro-bio, medical-engineering, Micro-electro-optics, Micro-mechanics, microelectronics etc.

Research on platforms - multidisciplinary large scale integration

What Can We Put On a Silicon Chip ?MEMS - Micro Electro Mechanical Systems

MEOMS - Micro Electro Optical Mechanical Systems

Micro-biological systems

Micro-Chemistry

Microelectronics

…..

MEMS Market and Industry StudiesThe MEMS/MST Market Worldwide, as estimated by J. Bryzek, 2001

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MEMS for Micro/Nano ObjectsThe Ultimate Integration

Multi functional silicon based system on a chip

Surface MicromachiningHow MEMS Are MadeA releasable hinge for a micro mirror

How MEMS Are MadeA bulk micro-machined pressure sensor

MEMS Processing Challenges:Stress Gradients

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Releasing MEMS: The Stiction ProblemMEMS Actuation Methods: Comb Drive

MEMS Actuation Methods: Comb DriveMicromachiningSingle crystal Bulk Micromachining

Trench

Bridge

Cantilevers

Wafer SurfaceCavity

Nozzle

Membrane

MicromachiningNon-crystalline Bulk Micromachining

surface

Cantilevers

Bridge

Trench

Nozzle

Cavity

Membrane

Surface Micromachining

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The Streamline of the ProcessThicker filmsdeeper etchesfewer steps

Removal of underlyingmaterials to releasemechanical structures

Special probing, sectioning and handling procedures to protect released parts

Encapsulate some parts of device but expose others

Test more than just electrical functions

DEPOSITION OF

MATERIALPATTERN

TRANSFER

REMOVAL OF

MATERIAL

Multiple Processing Cycles

PROBE TESTING

SECTIONING INDIVIDUAL DIE

ASSEMBLY INTO PACKAGE

PACKAGE SEAL

FINAL TEST

MEMS, Pollen and Red Blood-Cells

Drive gear chain and linkages

a grain of pollen

coagulated red blood cells

LIGA*, Deep UV

*Lithographie, Galvanoformung, Abformung = Litho, Electroplating, moldingSource: IMM (Mainz Institute for Microtechnology)

Irradiation

Development

Electroforming Mold Separation

Synchrotron

Resist

Resiststructure Plastic

moldmaterial

PlasticstructureMetal

Substrate

Mold cavityMold Filling

Absorberstructure

Mold Insert

Substrate

Maskmembrane

Wafer-to-Wafer Bonding

Create etch stops and gap in back

Fuse silicon

Process top and etch mass

Etch beam and bond Pyrex

Pyrex Air gap forsqueeze filmdamping

Device wafer

Mass wafer

Built-inover-accelerationstops

Sensingelements andinterconnections

Mass wafer

Research ThemesInertial Navigation Sensors

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Noise Problems in MEMS SensorsLow Noise Capacitive Inertial Sensors

Fabricated Micro-accelerometerMeasured and Estimated Noise Levels

MEMS Navigation SensorsMotion Tracker Applications

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Digital Tilting PZT Mirrors8 x 8 Switching Array of Digital Micro-mirrors(from Optical Micro Machines, Inc.)

Assembled 3-D structures: first hinged plateOptical Switch & Router

Projection DisplayRetina Display

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Microfluidics and Power ManagementSurface Micro-machined RF Device

Reflowed Solder Balls Used to Self-Assemble Fan Blades

Millipede Thermo-mechanical Data Storage System

Micro Airborne Sensor/Communicator

MEMS-Based Power Generation & Energy

Conversion

MEMSActuator

Inertial Measurement

UnitWhip

Antenna

MEMS Mass Data Storage

MEMS Microphone

MEMS UncooledIR Sensor

MEMS Optical

Communicator

MEMSStructural Material

Digital Printers and Injectors

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Biomolecules ManipulationLab on a Chip for DNA Analysis

The Electromechanical Single Electron Transistor Artur Erbe, Robert H. Blick, and J. P. Kotthaus - Phys. Rev. Lett. 87, 096106 (2001)

Electron transfer from source to drain, one by one…, like a pendulum

The Electromechanical Single Electron Transistor Artur Erbe, Robert H. Blick, and J. P. Kotthaus - Phys. Rev. Lett. 87, 096106 (2001)

One of the traditional experiments in the electrodynamics class is set up by two large capacitor plates and a metallized ball suspended in between the plates. Applying a constant voltage of some 100 V across the plates leads to the onset of periodic charge transfer by the ball bouncing back and forth, similar to a classical bell. The number of electrons transferred by the metallized ball in each revolution naturally depends on the volume of the metal, but can be estimated to be of the order of 1010 electrons. At an oscillation frequency of some 10 Hz up into the audible kHz-range this gives a typical current of 1 - 10 µA. The question arising is whether such an experiment can be performed on the microscopic level in order to achieve a transfer not of a multitude but of only one electron per cycle of operation at frequencies of some 100 MHz. Indeed this can be achieved by simply scaling down the setup and applying a nanomechanicalresonator as shown in the figure below. This electromechanical transistor (EMT) has the clear advantages of increased speed of operation and reduction of transfer rate, allowing to count electrons one by one. We observe transport of single electrons through a metallic island on the tip of the nanomachinedmechanical pendulum. The pendulum itself is operated by applying a modulating electromagnetic field in the range of 1 - 200 MHz, leading to mechanical oscillations between two laterally integrated source and drain contacts. The resulting tunneling current shows distinct features corresponding to the discrete mechanical eigenfrequencies of the pendulum.

Nanomechanical Resonators Laura Pescini, Heribert Lorenz, and Robert H. Blick

The Q factor of the suspended bar is measured at various temperatures and magnetic fields

Nanomechanical Resonators Laura Pescini, Heribert Lorenz, and Robert H. Blick

We investigate the mechanical properties of suspended silicon nanostructures. One of the devices is shown in left Figure. The Lorentz force which acts on the suspended nanowire when an ac signal is supplied and a magnetic field is present sets the wireinto motion as soon as the excitation matches the nanowire's eigenfrequency. The devices are fabricated out of Silicon-on-Insulator materials and a 40 nm thick gold layer is thermally evaporated on top of them to serve as a conducting path for the driving current. In the right Figure we show the temperature dependence of the quality factor Q defined as the ratio of the frequency to the full width at half maximum of the resonance. Here we have measured two resonant modes of one nanowire for several magnetic field intensities. The cross section of the measured wire is 100 nm x 120 nm with a length of 1200 nm. The presented Q values are referred to the 12 Tesla measurements however no magnetic field dependency of Q has been observed.

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Highly Sensitive Displacement Detection of Nanomechanical Resonators

Florian W. Beil, Laura Pescini, Eva M. Höhberger, Andreas Kraus, Artur Erbe, and Robert H. Blick

The displacement and linewidth of the resonator is measured using the capacitance with the side gates. Thin bars enable reduced linewisths

Highly Sensitive Displacement Detection of Nanomechanical Resonators

Florian W. Beil, Laura Pescini, Eva M. Höhberger, Andreas Kraus, Artur Erbe, and Robert H. Blick

Nanomechanical beam resonators are interesting mechanical systems due to their possible use as ultrasensitive sensors or filters for telecommunication applications allowing extra high integration densities. The measured linewidth of the mechanical resonancesis dependent on the detection mechanism applied. Motion of the resonator modulates the capacitance formed by the beam and an adjacent sidegate (fig. 1) thus enabling reduced measured linewidths compared to standard impedance reflection measurements. In general one could think of optimized gate geometries which reduce observed linewidths and thus maximize sensitivity.

Chaos in Nanomechanical SystemsDominik V. Scheible, Artur Erbe, and Robert H. Blick

The figure (a) shows the system of nano-mechanical resonators including signal wiring. As plotted in (b), the spectrum of displacement features the gradual split-up of the destinct peaks into multiple sub-peaks, indicating the transfer to chaos.

Chaos in Nanomechanical SystemsDominik V. Scheible, Artur Erbe, and Robert H. Blick

With the advent of nano-electromechanical systems (NEMS), a new class of devices is now introduced with possible applications in wireless information processing in the frequencyrange of 0.1 - 2 GHz. Driving amplitudes of nano-mechanical resonators can be enhanced, and the system might be brought into the nonlinear or even chaotic regime. In our experiment, we gradually transferred a system of freely suspended beam resonators from the linear regime to the realm of chaotic response. Excitation was carried out using a set of multiple frequencies, since the probability of choosing a region of chaos in parameter space increases with the number of present frequencies. The figure (a) shows the system of nano-mechanical resonators including signal wiring. As plotted in (b), the spectrum of displacement features the gradual split-up of the distinct peaks into multiple sub-peaks, indicating the transfer to chaos.

Requirements for FruitionSummary

Nano- and micro-mechanics are promising technologies with many applications

Integrated interdisciplinary efforts are required to promote this field

The ultimate goal is a lab on a chip