Lecture 02 history & characteristics of mems
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This document discusses the history and characteristics of microelectromechanical systems (MEMS). It outlines major developments in MEMS from the 1950s to the 2000s, including the first silicon strain gauges and pressure sensors, as well as the invention of surface micromachining. The document also describes three key characteristics of MEMS: miniaturization which allows for small, sensitive devices; microelectronics integration which combines mechanical and electronic components; and parallel fabrication which uses lithography to precisely pattern multiple identical structures.
Lecture 02 history & characteristics of mems
- 1. Dr. S.Meenatchi Sundaram, Department of Instrumentation & Control Engineering, MIT, Manipal ICE 4010: MICRO ELECTRO MECHANICAL SYSTEMS (MEMS) Lecture #02 History & Characteristics of MEMS Dr. S. Meenatchi Sundaram Email: meenasundar@gmail.com 1
- 2. Evolution of MEMS 2Dr. S.Meenatchi Sundaram, Department of Instrumentation & Control Engineering, MIT, Manipal
- 3. 1950’s • 1958 Silicon strain gauges commercially available • 1959 “There’s Plenty of Room at the Bottom” – Richard Feynman gives a milestone presentation at California Institute of Technology. Issues a public challenge by offering $1000 to the first person to create an electrical motor smaller than 1/64th of an inch. 1960’s • 1961 First silicon pressure sensor demonstrated • 1967 Invention of surface micromachining. Westinghouse creates the Resonant Gate Field Effect Transistor, (RGT). Description of use of sacrificial material to free micromechanical devices from the silicon substrate. 1970’s • 1970 First silicon accelerometer demonstrated • 1979 First micro machined inkjet nozzle History of MEMS 3Dr. S.Meenatchi Sundaram, Department of Instrumentation & Control Engineering, MIT, Manipal
- 4. 1980’s • Early 1980’s first experiments in surface micro machined silicon. Late 1980’s micromachining leverages microelectronics industry and widespread experimentation and documentation increases public interest. • 1982 Disposable blood pressure transducer • 1982 “Silicon as a Mechanical Material”. Instrumental paper to entice the scientific community – reference for material properties and etching data for silicon. • 1982 LIGA Process • 1988 First MEMS Conference 1990’s • Methods of micromachining aimed toward improving sensors. • 1992 MCNC starts the Multi-User MEMS Process (MUMPS) sponsored by Defense Advanced Research Projects Agency (DARPA) • 1992 First micro machined hinge • 1993 First surface micro machined accelerometer sold (Analog Devices, ADXL50) • 1994 Deep Reactive Ion Etching is patented • 1995 BioMEMS rapidly develop • 2000 MEMS Optical-networking components become big business History of MEMS 4Dr. S.Meenatchi Sundaram, Department of Instrumentation & Control Engineering, MIT, Manipal
- 5. History of MEMS 5Dr. S.Meenatchi Sundaram, Department of Instrumentation & Control Engineering, MIT, Manipal
- 6. Moore’s Law 6Dr. S.Meenatchi Sundaram, Department of Instrumentation & Control Engineering, MIT, Manipal Gordon Moore (Co-founder of Intel) predicted in 1965 that the transistor density of semiconductor chips would double roughly every 18 months.
- 7. Beyond Moore’s Law MOSFETs using new materials must be fabricated on Si substrates in order to fully utilize Si CMOS platform, meaning the necessity of the co-integration of III-V/Ge on Si. 7Dr. S.Meenatchi Sundaram, Department of Instrumentation & Control Engineering, MIT, Manipal
- 8. The three generic and distinct characteristics of MEMS devices are: – Miniaturization – Microelectronics Integration – Parallel Fabrication Miniaturization: • MEMS devices generally ranges from 1um to 1cm. • May rise to operational advantages, such as, – soft springs, – high resonance frequency, – Greater sensitivity – Low thermal mass (Ex: time constant of a ink jet nozzle is typically 20us) • Limited by scaling laws Characteristics of MEMS 8Dr. S.Meenatchi Sundaram, Department of Instrumentation & Control Engineering, MIT, Manipal
- 9. Microelectronics Integration: • Ability to seamlessly integrate mechanical sensors an actuators with electronics processors an controllers at the single wafer level. • Process paradigm referred to “Monolithic integration” • Examples as – Accelerometers, – Digital Light Processors (DLP), – Ink jet printer heads • Dimensions and precision of placement are guaranteed by lithography. • Quality of signals are improved by reducing noise and length of signal paths by monolithic integration. • In an DLP, each mirror is controlled by a CMOS logic circuit that is buried directly underneath. Characteristics of MEMS 9Dr. S.Meenatchi Sundaram, Department of Instrumentation & Control Engineering, MIT, Manipal
- 10. Parallel Fabrication: • Possible to realize two or three dimensional features with small dimension and high precision. • High aspect ratio. • High uniformity across wafers and batches. Characteristics of MEMS 10Dr. S.Meenatchi Sundaram, Department of Instrumentation & Control Engineering, MIT, Manipal