1. MEMS: Invention to Market
Invention->Market
Creation of a new market is slow.
Market->Invention (easier)
What is the existing competition?
Impact – will it take over the market?
Manufacturing
Sales
Modeling as in this course: Analysis of options, performance, price. Planning of R+D, business plan.

2. Device Categories Technology Demonstrations Research Tools
Test device concept
Test fabrication technology
Small # of devices/low yield ok
Research Tools
Small # of devices, often custom.
Commercial Products
Large # of devices, high yield, low cost, packaging all critical.

3. Transducers, Sensors, and Actuators
Transducers: Generally convert one form of energy to another. (Not generally conserving energy.)
Could be a sensor or an actuator.
Sensors measure something and provide an output signal. Usually electrical, but sometimes optical or mechanical.
Actuators move something. (But what would an LED be?)

4. Domains Thermal (temperature, heat, heat flow)
Mechanical (force, pressure, velocity, acceleration, position)
Chemical (concentration, composition, reaction rate)
Magnetic (magnetic field intensity, magnetization)
Radient (intensity, wavelength, polarization, phase)
Electrical (voltage, current, charge, resistance)

5. Examples of Sensors and Actuators
Position Sensors
Resistive strain sensor. (dimensions change, R=rl/A)
Piezoresistive strain sensor. (dimensions and r change)
Sensitivity measured by the gauge factor
GF=relative resistance change/strain=(DR/R)/(DL/L)=DR/eR
GF=~2 for metals (mostly geometry, some piezoresistance)
GF=~100 for semiconductors (piezoresistive)

6. Piezoelectric materials (Curies, 1880)
Electric field <-> strain (deformation)
Polarization <-> stress
Sensor/Actuator
In your watch, Quartz (but this is changing!! (Si Time))
Also pyroelectric materials have
temperature<->polarization.
Magnetostrictive Actuators
Materials expand/contract with magnetic field
Similar to piezoelectric effect
Terfenol-D Tb0.27Dy0.73Fe1.9 -> strain of 2X10-3 or 0.2%.

10. Sizes, again.
How big is 0.1Å?
Bohr radius (hydrogen) = 0.53Å = 0.053nm.
C-C bond (diamond) = 1.55Å = 0.155nm
Si-Si bond = 0.235nm
Si lattice constant = 0.54nm
Wavelength of green light = 5000Å.
Smallest commercial transistor: 25 nm
How big are MEMS?
What about NEMS?

14. Permanent magnetic materials
Micromirror, microrelay, micromotor
N S
N S B