Ee6007 Mems Question Bank

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R.M.K ENGINEERING COLLEGE DEPARTMENT DEPARTMENT OF EEE E EE Question Bank  Subjet Co!e " Na#e$ EE%&&' MICRO ELECTRO MEC(ANICAL S)STEMS

UNIT – I MEMS:MICRO-FABRICATION, MATERIALS  AND ELECTRO-MECHANICAL ELECTRO-MECHANICAL CONEPTS 

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PART * A List the the advantages advantages and and disadva disadvantages ntages of using piezoresistor piezoresistors? s? What are the principle principle applications applications of micro sensors? sensors? Write ite princip principle le of optical optical senso sensors rs in MEMS. MEMS. Write Wr ite the principle principle of thermal thermal sensor sensor in in MEMS. MEMS. Write Wr ite the principle principle of pressure pressure sensor sensor in in MEMS. MEMS. What What is is the the use use of acoustic acoustic sensor? sensor? #efine #efine resonan resonantt fre fre$u $uen enc% c%.. #efi #efine ne therm thermal al stress stress.. #iff #iffer eren enti tiate ate ()# and and *)#. *)#. #efine #efine ,et etching etching.. #efine #efine dr% etching etching.. What is is sputtering? sputtering? What is is L-/ process? #efine #efine o0idatio o0idation. n. #efine #efine diffusio diffusion. n. ive ive the the applications of MEMS in iomedical. (ompare the scaling la, in in miniaturization of devices devices ased on electrostatic el ectrostatic and electromagnetic principles. State the materials materials that that are used used as piezoresistors. #ra, the steps sho,ing photolithograph% process. process. What is is called deep reactive ion etching? ive ive three e0amples of the oects that %ou %ou are personall% recognize to e of the size of appro0imatel% 1mm. ive ive at least four distinct advantages of miniaturization of machines and devices. or order 1 scaling such as surfacetovolume scaling5 the acceleration varies varies 617 linearl%5 627 to the s$uare po,er5 637 to the cuic po,er. 8eat flo, flo,ss 617 faster5 faster5 627 slo,er5 637 aout the same in a smaller solid than in a larger solid. What is is a sustrate? sustrate? Wh% silicon is an ideal material for MEMS? MEMS? What do %ou %ou mean % scaling la, in in MEMS? List the the t%pes t%pes of ()#. #efine #efine etch rate rate.. #efine #efine stress and and strain. strain. List t%pes of eams. #efine #efine intrinsi intrinsicc stress. #efine resonant fre$uenc% and $ualit% factor.

PART * B 1. #iscuss in detail the properties of silicon as a sustrate material. 2. (ompare and contrast MEMS technolog% and microelectronics. 3. #iscuss in detail the MEMS farication processes9 6i7 :0idation. 6ii7 Etching. 4. #iscuss in detail the MEMS farication processes9 6i7 *hotolithograph%. 6ii7 -on -mplantation. . What ,ould happen to the re$uired tor$ue to turn a micro mirror With +; reduction in size? !. Estimate the associated changes in the acceleration a and the time t and the +o,e- su++/ to actuate a MEMS component if its ,eight is reduced % afactor of 1+. ". ind the reduction of electrostatic forces generated % a pair of  parallel*late electrodes 6having length L5 ,idth 0 and separated  % a distance !1 if oth the length L and the ,idth W of these  plates are reduced % a factor of 1+. &. micro machined parallel plate capacitor  serving as a differential mode tactile sensor. 11. With neat diagram e0plain the farication process of tactile sensor. 12. With neat diagram e0plain 6a7 com drive5 67 transverse com drive and 6c7 longitudinal com drive. UNIT-III THERMAL SENSING AND ACTUATION 

PART * A 1. #efine thermal resistance in the case of conduction5 convection and radiation. 2. Write principle of thermal couples. 3. What do %ou mean % thermal sensors? 4. What do %ou mean % thermal actuators? . #efine thermal conduction. !. #efine natural thermal convection. ". #efine forced thermal convection. &. #efine volumetric thermal e0pansion coefficient. '. #efine linear e0pansion coefficient. 1+. Write the principle of thermal imorph principle. 11. #efine temperature coefficient of resistance. 12. Write the principle of hot ,ire anemometer. PART * B 1. E0plain thermal imetallic ending and find vertical displaceme nt at he free end of the cantilever eam. 2. With neat diagram e0plain imetallic artificial cilia actuator. 3. With neat diagram e0plain pol%imide thermal actuator. 4. With neat diagram e0plain lateral thermal actuator. . E0plain thermal couple element ,ith neat diagram and dra, the -) characteristic of a thermal resistor. !. E0plain thermal accelerometer ,ith and ,ithout moving mass ,ith neat diagram. ". With schematic diagram e0plain single outofplane hot ,ire anemometer. &. E0plain the farication process of a surface micromachined hot,ire anemometer. '. With schematic diagram e0plain thermal shear stress sensor and farication  process. 1+. With neat diagram e0plain infrared thermal sensor. 11. With schematic diagram e0plain the enpoint sensor.

UNIT-IV PIEZOELECTRIC SENSING AND ACTUATION 

PART * A

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#efine *iezoelectric effect. #efine electromechanical coupling coefficient. Write the properties of *iezo electric materials. What is the principle of acoustic sensor? Write the governing e$uations of direct effect of piezoelectricit%. Write the governing e$uations of inverse effect of piezoelectricit%. List the commonl% used *iezo electric materials. Write the principle of surface elastic ,ave devices. PART * B E0plain *iezo electric actuator model ,ith neat diagram. With neat diagram e0plain *iezo electric accelerometer. With schematic diagram e0plain piezoelectric microphone and its farication  process. With schematic diagram e0plain cantilever t%pe piezoelectric microphone. E0plain tactile sensor arra% ,ith neat diagram. E0plain piezoelectric flo, sensor ,ith neat diagram. E0plain surface acoustic ,ave and fle0ural plate ,ave ,ith neat diagram. UNIT-V CASE STUDIES 

PART * A 1. #efine gauge factors for longitudinal and transverse cases for silica. 2. #ifferentiate longitudinal and transverse piezoresistors. 3. What do %ou mean % single cr%stal silicon? 4. List the applications of piezoresistive sensors. . #efine magnetization. !. #efine Lorentz force on a current carr%ing ,ire. ". List the micro fluidic applications of MEMS. &. List the medical applications of MEMS. PART * B 1. E0plain piezoresistive sensor materials in detail. 2. With neat diagram e0plain stress in fle0ural cantilevers. 3. With neat diagram e0plain the farication of silicon proof mass ,ith cantilever. 4. With schematic diagram e0plain artificial hair cell element ,ith farication  process. . E0plain the process for electroplating of magnetic materials ,ith neat diagram. !. E0plain design and farication processof magnetic coil. ". E0plain electrophoresis and dielectrophoresis ,ith neat diagram. &. With schematic diagram e0plain an integrated gas chromatograph% s%stem. '. E0plain optical MEMS in detail. 1+. E0plain BEMS devices in detail.