MEMS
MODULE I
SYLLABUS
• MEMS and Microsystems: Applications – Multidisciplinary nature of MEMS –
• principles and examples of Micro sensors and microactuators – micro accelerometer
• –comb drives - Micro grippers –
• micro motors, micro valves, micro pumps, Shape Memory Alloys.
• Review of Mechanical concepts: Stress, Strain, Modulus of Elasticity, yield strength, ultimate
strength – General stress strain relations –
• compliance matrix. Overview of commonly used mechanical structures in MEMS - Beams,
Cantilevers, Plates, Diaphragms – Typical applications
WHAT IS MEMS
• MICRO-ELECTRO-MECHANICAL SYSTEMS
• MICROSENSORS+MICROACTUATORS+
MICROPROCESSORS= MEMS
• SENSORS:::
Pressure
Temperature
Motion
MEMS IS
• Micro Electro Mechanical Systems are physically small in size, this is the
reason why MEMS are useful.
• MEMS sensors interfere less with the environment and they sense the
signals better than larger devices.
• The motion of MEMS actuators are very precise.
• MEMS devices can be placed in small places such as inside
automobile engines, small appliances and living organisms to measure
the various parameters
• MEMS devices offer tight integration of electronics with mechanical
components which result in very low power consumption and fast
response times.
PRESSURE SENSOR- WHY SMALL???
IS MEMS AN IC???
MULTIDISCIPLINARY NATURE
• ELECTROCHEMISTRY
• ELECTROHYDRODYNAMICS
• MOLECULAR BIOLOGY
• PLASMA PHYSICS
• SCALING LAWS
• QUANTUM PHYSICS
• MOLECULAR PHYSICS
• ENGINEERING DISCIPLINE
COMPONENTS
MEMS
MICROSENSOR
MICROSENSORS
• These are built to sense the existence and the intensity of certain
Physical
Chemical, or
Biological
Examples: temperature, pressure, force, sound, nuclear radiation,
magnetic flux and chemical compositions
COMMON SENSORS
• BIOSENSORS
• CHEMICAL SENSORS
• OPTICAL SENSORS
• THERMAL SENSORS
• PRESSURE SENSORS
PRESSURE SENSOR- WORKING PRINCIPLE
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An input signal such as pressure is sensed
By a micro sensing element
Which may be a simple silicon diaphragm
Only a few micrometers thick
The deflection of the diaphragm
Is converted into change of electrical resistance
By micropiezoresistors that are in diaphragm
Converted to voltage values
OUTPUT: VOLTAGE VALUES
MICROACTUATORS