Kutz M. Handbook of materials selection

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Table 2 Summary of Selected Communication System Components

Material Synthetic Technique Property Component Function System / Network

Ag Sputtering, evaporation,

electrochemistry

Electrical and thermal con-

ductor

Optoelectronic packaging Heatsink (interconnection) Networks, pack-

aging

Al Sputtering, evaporation Conductor, reﬂective (visi-

ble)

Interconnects, optical MEMS Electrical conductor, reﬂective

surface

Wireless, optical

AlN Sputtering, CVD Piezoelectric MEMS Sensor / transducer materials, actu-

ation method

Wireless

Au Evaporation Excellent optical reﬂectiv-

ity at 1.55

␮

Optical cross connect (OXC) Mirror used to route optical sig-

nals in MEMS OXC

Optical

Au Sputtering, evaporation Reﬂective (infrared), con-

ductor

MEMS Interconnection, reﬂective surface

in optical MEMS, bonding pad

All

Au–Sn Evaporation of multilayers,

bulk

Low-melting-point alloy Packaging Method of package sealing and

interconnection

All

Ceramic sintering High dielectric constant,

low TCK

Resonator High-Frequency band pass ﬁlter Wireless

Cr Sputtering, evaporation Intermediate adhesion layer MEMS Adhesion layer All

Cu Wire drawing Very low electrical resistiv-

ity

Cable Transmit electrical signals Cable

Cu Electrodeposition Very low electrical resistiv-

ity

Integrated circuit interconnects Carries current between transis-

tors and other electrical compo-

nents in an integrated circuit

All

Cu Sputtering, evaporation,

plated

Conductor MEMS Interconnection All

Diamond-

like car-

bon

Sputtered, ion-beam, CVD Hard, wear resistant, corro-

sion resistant

MEMS Durable ﬁlm Optical

Epoxy Organic synthesis UV curable Modulator Bonds optical ﬁber to planar wav-

eguides

Optical

Glasses Sintering, spin-on Hermetic Packaging Sealant, portal All

In Evaporation Low-melting-point metal Interconnection, packaging Solder joints All

InGaAs MBE Small direct bandgap semi-

conductor

2.5

␮

m photodetector Detect light Optical

1332

Table 2 (Continued )

Material Synthetic Technique Property Component Function System / Network

InGaAsP MOCVD Small direct bandgap semi-

conductor

Lasers and photodectors Convert electrical energy to light Optical

InP MOCVD Small direct bandgap semi-

conductor

Optoelectronic switch Route optical signals Optical

LiNbO

Czochralski growth of sin-

gle crystals

Electro-optic Modulator Imprints RF data stream onto

continuous-wave optical signal

using optical interference

Optical

LiNbO

Czochralski growth of sin-

gle crystals

Electro-optic Attenuator Decreases intensity of light propa-

gating in a waveguide

Optical

LiTaO

Czochralski growth of sin-

gle crystals

Piezoelectric Surface acoustic wave High-frequency ﬁlter Wireless

Methyl methac-

rylate

Polymerize then drawn Optically transparent Plastic optical ﬁber core Light waveguide Optical

Ni Sputtering, evaporation,

plating

Magnetic MEMS, packaging Magnetic tranducing, diffusion

barrier

All

NiTi Sputtering Shape memory alloy MEMS actuation Thermal actuation Optical

Paralenes Gas-phase polymerization Low-temperature confor-

mal conductive protec-

tive ﬁlm

Packaging Protection of electrical circuitry

and MEMS devices

Optical

Pb(Zr,Ti)O

Sol–gel, sputtering Electro-optic Modulator, switch Imprint data stream, switch opti-

cal signals between waveguides

Optical

Pd Plating, sputtering, evapo-

ration

Inert noble metal High-temperature/ power Interconnection Wireless

Permalloy

(Ni

)

Electroplated Magnetic Magnetic cores Magnetic tranducing MEMS, IC

Photoresist Spin-on Photosensitive, structural

material

Component fabrication Masking and etching template,

LIGA molds

Optical MEMS

Polyethylene — Electrical insulator Sheath Provides liquid water barrier and

electrical insulation

Cable

Poly-Si CVD Resistive, mechanical

strength

MEMS structures, integrated cir-

cuits

Mechanical element in MEMS MEMS, optical

1333

Polystyrene Drawn from preform Guides light Plastic optical ﬁber cladding Contains light in ﬁber

PZT (lead zir-

conate titan-

ate)

Crystal growth, sputtered Piezoelectric MEMS Actuation Optical

Si Crystal growth Semiconducting, mechani-

cal element

Integrated circuits, MEMS Conductive path, mechanical

structure, substrate

Optical, wireless,

MEMS

SiC CVD Semiconducting, hard, con-

ductive, stiff, and wear

resistant

MEMS Semiconductor, sensor material,

wear resistant

MEMS

Silicone rubbers Thermally cured process Conformal protective seal,

electrically conductive

Packaging Encapsulant Optical, wireless

SiN CVD Passivation, mechanical el-

ement

MEMS structures Tailorable passivation, protective

layer

Optical, wireless

SiO

Sol–gel Optically transparent Optical ﬁber Conﬁnes optical signal Optical

SiO

PECVD (plasma enhanced

chemical vapor deposi-

tion)

— Arrayed waveguide grating

(AWG)

——

SiO

MCVD, CVD, thermally

grown, spin-on

Preferentially etched stable

oxide, thermal and elec-

trical insulation

MEMS structure and integrated

circuit material

Electrical and thermal insulation,

MEMS sacriﬁcial layer, optical

ﬁber cores

MEMS, IC, opti-

cal ﬁber

SiO

:Ge MCVD (modiﬁed chemical

vapor deposition)

Higher refractive index

than pure SiO

Core of optical ﬁber Carries optical signal Optical

SiO

:Ge MCVD Photorefractive Fiber Bragg gratings Filters single wavelength or modi-

ﬁes pulse characteristics

Optical

TBCCO Thin-ﬁlm deposition Superconducting Resonator High-frequency band pass ﬁlter Wireless

Teﬂon Polymerized then extruded Protective sheath Plastic ﬁbers Cladding Optical

Ti Sputtering, evaporation Sticks to most surfaces Metallization Intermediate adhesion layer Optical, wireless,

MEMS

TiN CVD, PVD Passivation protection MEMS Diffusion barrier material Optical, wireless,

MEMS

W Sputtering, evaporation High-temperature metal Packaging High-temperature interconnect,

diffusion barrier

All

ZnO Reactive sputtering Piezoelectric MEMS Transducer material Optical

1334 ADVANCED MATERIALS IN TELECOMMUNICATIONS

Fig. 17 A simpliﬁed schematic of the sputtering process.

ination usually from the ﬁlament.

In addition, the materials to be evaporated

are limited by the temperatures (or power levels) that can be established.

Electron-beam evaporation eliminates these disadvantages and for this reason

has become widely used for depositing pure ﬁlms. In principle, virtually all

materials can be evaporated by this type of source.

For electron beam evapo-

ration, the evaporant material is placed in a water-cooled crucible. Electrons are

thermionically emitted by heated ﬁlaments and guided by electromagnets fo-

cused into the crucible. The energy from the electrons melts a region of the

target. The material evaporates from the source and covers the suspended sub-

strate with a thin ﬁlm. Commonly used for metallization, wafers mounted above

the source are typically rotated to ensure uniform coverage and are sometimes

radiantly heated to promote adhesion and uniformity.

4.4 Chemical Vapor Deposition

Chemical vapor deposition (CVD) forms ﬁlms by thermal decomposition or

chemical reaction of gases. The desired materials are deposited directly from the

gas phase onto the surface of the substrate. A beneﬁt of this technique is that

conformal ﬁlms can be made; that is, ﬁlms that coat the entire geometry of the

substrate’s features. Other physical deposition techniques such as evaporation

and sputtering are limited on conformality due to shadowing effects caused by

features that block the path of depositing material. Drawbacks of CVD are that

high temperatures (several hundred degrees) are required and suitable reactant

gases do not always exist. Several materials used in telecommunications are

routinely deposited by this technique, including silicon dioxide and silicon ni-

tride. Metals used for interconnects and barrier layers, such as tungsten, tanta-

lum, titanium, and molybdenum, are also deposited by this means.

CVD is

also a technique of choice to achieve epitaxial semiconductor ﬁlms. These ﬁlms

are important for semiconductors for photonic devices (laser, photodiodes, and

others) as well as microelectronic devices,

in which perfect registry is required

to reduce loss or attenuation during transmission. A modiﬁed form of CVD is

4 SYNTHETIC METHODS 1335

used in the development of optical ﬁber and is discussed in the optical ﬁber

section.

4.5 Epitaxy

The word epitaxy is Greek in origin: epi means ‘‘on’’ and taxis means ‘‘arrange-

ment.’’ Speciﬁcally, epitaxy concerns itself with the arrangement of atoms di-

rectly on top of other atoms. This technique provides a means of controlling

doping proﬁles and forming single-crystal ﬁlms so that devices can be optimized.

Epitaxial layers can be formed by growth techniques of vapor phase,

81,84,85

liquid

phase,

31,86

or molecular beam.

87–89

In the vapor-phase version, the substrate wafer acts as the seed layer. Growth

temperatures in this technique are also considerably lower than the melting point

(about 30–50% lower).

In it, layers are deposited directly from the gas phase.

In a typical reactor, either RF inductive coupling or radiative energy heats the

substrates. A carrier gas is ﬂowed over the substrate surface initiating a reaction.

Epitaxial layers may also be doped by the adding of impurities to the gas of

deposition. In this way, the varying of the partial pressure of the dopant species

can control the resistivity. For silicon epitaxy, the growth rate ranges from 0.6

to 1

␮

m/min.

In the liquid-phase version, the growth of epitaxial layers occurs by direct

precipitation of the liquid phase. The reactant solution containing the materials

to be deposited cascades the surface of the substrate in a heated environment.

The substrate acts as a seed layer for crystallization. Growth rates typically range

between 0.1 and 1

␮

m/min.

Liquid-phase epitaxy (LPE) is useful for multi-

layer ﬁlms in which precise doping and composition are required. Commonly

used for gallium arsenide and other III–V compounds, limitations of this tech-

nique include poor thickness uniformity and rough surface morphology. This

technique has been replaced by CVD and by molecular beam epitaxy for some

applications.

Molecular beam epitaxy (MBE) involves the reaction of one or more thermal

beams of atoms with a crystalline surface at ultrahigh vacuum (with pressures

of 10

⫺

torr or lower). Substrate temperatures range form 400 to 900⬚C, and

the growth rate is relatively low at 0.001–0.3

␮

m/min.

MBE can precisely

control both chemical species and doping proﬁles with dimension control on the

order of atomic layers.

Two types of epitaxial growth may be distinguished: homoepitaxy and het-

eroepitaxy. Homoepitaxy occurs when the ﬁlm and substrate are the same ma-

terials; for example, epitaxial (epi) Si deposited on a Si substrate. An epi layer

is desired because it is freer from defects. In addition, impurities of controlled

amounts are also attainable.

The importance of this technique arises from the

need to control resistivity (by doping levels) and conductivity type (n or p)of

which epitaxial ﬁlms can be controlled independent of the substrate.

Heteroepitaxy occurs when ﬁlms and substrates are of different materials,

such as AlAs on a GaAs substrate. In these conﬁgurations, heterojunctions, or

interfaces between two single crystals of differing compositions or doping, are

made that create materials of differing bandgaps. These conﬁgurations conﬁne

charge, which helps achieve a high level of radiative recombination in the active

region of the device, thus yielding a high quantum efﬁciency.

Optoelectronic

1336 ADVANCED MATERIALS IN TELECOMMUNICATIONS

Fig. 18 A schematic of (a) the ﬂoat zone process and (b) Czochralski crystal pulling apparatus.

devices such as light-emitting diodes and lasers are based on compound semi-

conductor heteroepitaxial ﬁlm structures.

Lasers also employ the contrast in

electrical properties at heterojunctions to pump electrons into higher states (or

invert electron populations)

so that when they fall to lower ones, they discharge

a photon.

4.6 Crystal Growth

Some semiconducting materials are deposited epitaxially by CVD, while others

are grown from melts. In crystal growth,

two prominent methods are used: (a)

the related techniques including ﬂoat zone, Bridgman, or Stockbarger, in which

the molten material is cooled slowly through a small temperature difference,

which causes it to solidify,

and (b) the Czochralski method in which a rotating

seed crystal is pulled slowly from the melt and in turn grows successive layers

frozen at the solid–liquid interface

(both are depicted in Fig. 18). One critical

requirement for crystal growth by these techniques is that the material must melt

congruently, in other words, the melt composition must be the same as the crystal

composition. Common materials grown by the Czochralski technique are single

crystals of silicon (with a melting point of 1414

⬚C) and gallium arsenide (with

a melting point of 1238

⬚C). After growth and surface ﬁnishing, the ingot is cut

with a diamond tip saw into slices or wafers. These wafers are then evaluated

for resistivity, polished, and loaded into plastic trays.

Other crystals important for telecommunications are also developed by this

technique. They include semiconductors such as Ge, compound semiconduc-

tors

such as GaAs, GaP, InAs, InSb, AlSb, and InP, modulator materials such

as LiNbO

, and ferrites such as garnets.

5 VISION OF FUTURE COMMUNICATION COMPONENTS 1337

4.7 Plating

Electrodeposition is a method of depositing metals and alloys by means of elec-

trochemical reactions. Generally, this deposition technique requires an aqueous

solution that contains metal salts. In the process, the metal ions gain an electron

(and thus are reduced) and, in turn, are deposited. There are two major ap-

proaches: electrolytic and electroless. The main difference is how the electrons

used for reduction are supplied. In electrolytic deposition they are supplied by

an external source such as a battery or power supply. In electroless plating, they

are supplied by a chemical reducing agent in the solution.

Electrolytic deposition is discussed widely.

The range of uses of electroless

deposition in telecommunications is quite formidable. Several metals

95,96

are

commonly plated electrolessly including nickel, copper, cobalt, gold, silver, pal-

ladium, platinum, and rhodium. Electroless solutions contain the metal salt, a

reducing agent, a buffer (pH adjuster), stability additives for desired properties,

and a complexing agent. Because the metal salt and reducing agent are con-

sumed, they must be replenished. This approach is advantageous because both

conductive and nonconductive surfaces can be plated. In addition complex

shapes can be plated and no special anodic assemblies are needed. Equipment

needs are simple as well, for they entail plating tanks and precise temperature

regulation. This technique is used in telecommunication power systems such as

copper coils for inductors and also in their associated magnetic layers. Electro-

less deposition is also a means for ﬁber metallization.

5 VISION OF FUTURE COMMUNICATION COMPONENTS

Imagine walking down Broadway in Manhattan and bumping into a friend from

days past. Spontaneity takes over and you want to ﬁnd a cozy coffee shop to

reminisce over a cappuccino. Where’s the nearest coffee shop? Do they serve

cappuccino? What are their hours?

In addition, with the advent of smart cards and radio-frequency identiﬁcation

(RFID) tags, consumers will be able to walk through the checkout at the book-

store, grocery store, or clothing boutique without having to scan individual items

or removing their wallet—the amount will be deduced from your e-money credit

or debit card.

Communications technology is already starting to deliver some of these ser-

vices. Wireless data lend rudimentary access to the Internet and with the aid of

the global positioning system (GPS) your precise location can be identiﬁed. Grab

your cellular phone and call to see if any tables are unoccupied. Viola`!

Unfortunately, most of these services are in their infancy and only provided

on separate hardware. For example, the Palm VII personal digital assistant allows

download of simple website data, and GPS handheld units typically only provide

a map centered about a given location.

On another revolutionary front, digital

cellular phones are being developed with large bandwidth in order to access the

Internet. Many telecom companies are developing and implementing third-

generation (3G) wireless networks.

This only describes the wireless arena. What could you do if you had a ﬁber-

optic connection in your home? Forget returning movies to the rental store down

the street. Download your favorite movie in real time in HDTV wide format for

1338 ADVANCED MATERIALS IN TELECOMMUNICATIONS

display on a large screen using high-luminosity projectors. The audio and visual

quality will surpass that of the movie theater, and you won’t have any gum stuck

to the bottom of your shoe. The only requirement here is an optical modem,

which will be available soon at a reasonable price. Of course, the same ﬁber

will carry voice, data, and video.

What is the vision for materials research? Long-term fundamental research

toward controlling the behavior of dopants and defects in solid-state materials

will be the challenge for the next several decades. The task of understanding

inorganic solids is challenging enough given the thousands of structure types

along with variable stoichiometry, but to also consider dopants that encompass

most of the periodic table of elements makes the task nearly impossible. Yet,

impurities on the order of parts per billion dictate the electronic properties of

semiconductors and insulators. With this type of knowledge, engineers could

design structures on the atomic scale.

Focusing on short-term research in materials for wireless devices and net-

works, areas that show promise for future incorporation into telecommunication

systems are photonic bandgap antennas, phased array antennas,

fuel cells, and

soft radio (i.e., further integration such that an entire phone can ﬁt in a package

about the size of a credit card).

To improve optical devices and networks, materials research is necessary in

the following areas: (1) organic materials have advantages in tailoring at the

molecular level and mechanical ﬂexibility as seen in the design of plastic tran-

sistors for digital paper,

and the major limitation is poor reliability of organic

materials due to decomposition from high-intensity light, high temperature, wa-

ter vapor, and oxygen; and (2) advances in the integration of inorganic materials

especially in the form of thin ﬁlms, where birefringence in waveguides prevents

many planar analogs to ﬁber devices, are needed.

Predictions for future communication systems suggest advances in optical

networking to reduce cost of optoelectronic devices and in wireless networks to

increase bandwidth, perhaps by utilizing higher frequencies are necessary. Op-

tical networking has yet to take advantage of the integration and miniaturization

that has propelled the microelectronics industry. The ﬁrst step is to incorporate

separate components and functionalities into the same package using either free-

space optics or waveguide technology as seen in modulator and attenuator pack-

ages. Next, integrating these components onto the same substrate or wafer can

greatly reduce cost, for example, in electroabsorption modulated lasers (EMLs).

Finally, to easily connect ﬁbers to wafers will complete the manufacturing pro-

cess.

100

The future looks bright for optical communication!

REFERENCES

1. R. L. Freeman, Fundamentals of Telecommunications, Wiley, New York, 1999.

2. F. T. S. Yu, Optics and Information Theory, Wiley, New York, 1976, p. 29.

3. S. T. Brewer, Signal Transmission: Communications Cable, Communications Source Book, S. P.

Parker (ed.), McGraw-Hill, New York, 1987.

4. D. N. Chorafas, Telephony: Today and Tomorrow, 1984, Prentice-Hall, Englewood Cliffs, NJ,

1984, p. 127.

5. P. P. Mitra, and J. B. Stark, ‘‘Nonlinear Limits to the Information Capacity of Optical Fibre

Communications,’’ Nature, 411, 1027 (2001).

REFERENCES 1339

6. S. R. Nagel, in Signal Transmission: Communications Cable, Communications Source Book,

S. P. Parker (ed.), McGraw-Hill, New York, 1987.

7. M. J. Riezenman, ‘‘Optical Nets Brace for Even Heavier Trafﬁc,’’ IEEE Spectrum, 2001 January,

(2001).

8. W. Sweet, ‘‘Cell Phones Answer Internet’s Call,’’ IEEE Spectrum, August, 42 (2000).

9. L. T. Manzione, Plastic Packaging of Microelectronic Devices, Van Nostrand Reinhold, New

York, 1990.

10. D. W. Johnson, and J. Thomson, ‘‘Ceramic Pakaging for Telecommunications,’’ Ceramic Trans.,

33: 141 (1993).

11. C. A. Steidel, ‘‘Assembly Techniques and Packaging,’’ in VLSI Technology, S. M. Sze (ed.),

McGraw Hill, New York, 1983.

12. H. H. Manko, Solders and Soldering, 2nd ed., McGraw-Hill, New York, 1979, p. 350.

13. J. C. Dyment, and L. A. D’Asaro, ‘‘Contiuous Opertation of GaAs Junction Lasers on Diamond

Heatsinks at 200K,’’ Appl. Phys. Lett., 11(9), 292–293 (1967).

14. T. Tsukada, and Y. Shima, ‘‘Thermal Characteristics of Buried Heterostructure Injection Lasers,’’

IEEE J Quant Electron, QE-11(7), 494–498 (1975).

15. K. Fujiwara, et al., ‘‘Analysis of Deterioration in In Solder Used for GaAlAs DH Lasers,’’ Appl.

Phys. Lett., 35(11), 861–863 (1979).

16. A. R. Mickelson, N. R. Basavanhally, and Y.-C. Lee (eds.), Optoelectronic Packaging, Wiley

Series in Microwave and Optical Engineering, Wiley, New York, 1997.

17. S. A. Merritt, et al., ‘‘Semiconductor Laser and Optical Ampliﬁer Packaging,’’ in Optoelectronic

Packaging, A. R. Mickelson, N. R. Basavanhally, and Y.-C. Lee, (eds.), Wiley, New York, 1997,

pp. 59–78.

18. K. Gileo, ‘‘MEMS Packaging Issues and Materials,’’ in Advancing Microelectronics, 2000, pp.

9–13.

19. C. H. Lee, Picosecond Optoelectronic Devices, Academic, Orlando, FL, 1984.

20. M. Ohring, Engineering Materials Science, Academic, New York, 1995, p. 127.

21. W. F. Brinkman, et al., ‘‘The Lasers Behind the Communications Revolution,’’ Bell Labs Tech.

J., 5(1), 150–167 (2000).

22. R. E. Slusher, ‘‘Laser Technology,’’ Rev. Mod. Phys., 71(2), p. S471 (1999).

23. H. F. Wolf, Handbook of Fiber Optics: Theory and Applications, Garland STPM Press, New

York, 1979.

24. M. D’Hondt, et al., ‘‘Inﬂuence of Buffer Layer and Processing on the Dark Current of 2.5

␮

Wavelength 2% Mismatched InGaAs Photodetectors,’’ IEEE Proc.-Optoelectron., 144(5) 277

(1997).

25. K. Booth, and S. Hill, The Essence of Optoelectronics, The Essence of Engineering Series,

Prentice Hall, London, 1988.

26. J. Hecht, Understanding Fiber Optics, SAMS, Indianapolis, 1993.

27. V. S. Arunachalam, and S. Mahajan, ‘‘Role of Materials in Lightwave Communications,’’ Z.

Metallkd, 90(11), 914–919 (1999).

28. J. Hecht, Understanding Fiber Optics, 3 ed., Prentice Hall, Upper Saddle River, NJ, 1999.

29. G. W. Morey, The Properties of Glass, Reinhold, New York, 1954.

30. W. D. Kingery, H. K. Bowen, and D. R. Uhlmann, Introduction to Ceramics. 2nd ed., Wiley

Series on the Science and Technology of Materials, ed. E. Burke, B. Chalmers, and J. A. Krum-

hansl (eds.), Wiley, New York, 1976.

31. G. Keiser, Optical Fiber Communications, Communications and Information Theory, S. W. Di-

rector (ed.), McGraw-Hill, New York, 1983.

32. P. C. Becker, N. A. Olsson, and J. R. Simpson, Erbium Doped Fiber Ampliﬁers: Fundamentals

and Technology, Academic, San Diego, 1999.

33. R. Kashyap, Fiber Bragg Gratings. Optics and Photonics, P. L. Kelly, I. Kaminow, and G.

Agrawal, (eds.), Academic, New York, 1999, p. 458.

34. H. D. Ackler, and J. B. MacChesney, ‘‘Optical Silica Fibers,’’ in Advanced Inorganic Fibers:

Process, Structure, Properties, Applications, F. T. Wallenberger (ed.), 2000, Kluwer Academic,

Boston, 2000, pp. 169–201.

35. A. Weinert, Plastic Optical Fibers, Munich, 1999.

36. F. P. Kapron, D. B. Keck, and R. D. Maurer, ‘‘Radiation Losses in Glass Optical Waveguides,’’

Appl. Phys. Lett., 17, 423–425 (1970).

1340 ADVANCED MATERIALS IN TELECOMMUNICATIONS

37. J. B. MacChesney, P. B. O’Conner, and H. M. Presby, ‘‘A New Technique for Preparation of

Low-Loss and Graded Index Optical Fiber,’’ Proc. IEEE, 62, 1280–1281 (1974).

38. A. Othonos, and K. Kalli, Fiber Bragg Gratings: Fundamentals and Applications in Telecom-

munications and Semsing, Artech House, Norwood, MA, 1999.

39. J. A. Rogers, ‘‘Rubber Stamping for Plastic Electronics and Fiber Optics,’’ Mat. Res. Soc. Bull.,

26(7), 530 (2001).

40. G. Lenz, et al., ‘‘Large Kerr Effect in Bulk Se-based Chalcogenide Glasses,’’ Optics Lett., 25(4),

254 (2000).

41. A. J. Moulson, and J. M. Herbert, Electroceramics: Materials, Properties, Applications, NY:

Chapman & Hall, New York, 1990, p. 348.

42. C. Bosshard, et al., Organic Nonlinear Optical Materials, Gordon and Breach, Basel, 1995.

43. J. Hullinger, P. J. Langley, and S. W. Roth, ‘‘A New Design for Efﬁcient Electro-optic Single-

Component Organic Crystals,’’ Crystal Eng., 1(3 /4), 177 (1998).

44. C. Sanchez, and B. Lebeau, ‘‘Design and Properties of Hybrid Organic-Inorganic Nanocompos-

ites for Photonics,’’ Mat. Res. Soc. Bull., 26(5), 377 (2001).

45. R. E. Hummel, Electronic Properties of Materials, 2nd ed., Springer, Berlin, 1992.

46. M. Ohring, Engineering Materials Science, Academic, New York, 1995.

47. V. J. Fratello, S. J. Licht, and C. D. Brandle, ‘‘Compositional Design of Faraday Rotator Ma-

terials,’’ Mat. Res. Soc. Symp. Proc., 574, 225 (1999).

48. M. Elwenspoek, and R. Wiegerink, Micromechanical Microsensors, Microtechology and MEMS,

Springer, Berlin, 2001.

49. D. A. Horsely, R. Horowitz, and A. P. Pisano, IEEE-ASME Trans. Mechatronics, 3, p. 175 (1998).

50. A. H. Epstein, and S. D. Senturia, Science, 276, 1211 (1997).

51. T. Liakopoulos, and C. Ahn, 3-D ‘‘Microfabricated Toroidal Planar Inductors with Different

Magnetic Core Schemes for MEMS and Power Electronic Applications,’’ IEEE Trans. Magnetics,

SEP, 35(5), 3679–3681 (1999).

52. C. Giles, V. Aksyuk, and B. Barber, ‘‘A Silicon MEMS Optical Switch Attenuator and Its Use

in Lightwave Subsystems,’’ IEEE J. Select. Topics in Quantum Elec., 5(1), 18–25 (1999).

53. M. Koch, C. Schabmueller, and A. Evans, ‘‘Micromachined Chemical Reaction System,’’ Sensors

and Actuators A-Physical, APR 20, 74(1–3), 207–210 (1999).

54. D. M. Gruen, ‘‘Nanocrystalline Diamond Films,’’ Ann. Rev. Mat. Sci., 29, 211–259 (1999).

55. N. Rajan, C. Zorman, and M. Mehregany, ‘‘Effect of Mems Compatible Thin Film Hard Coatings

on the Erosion Resistance of Silicon Micromachined Atomizers,’’ Surface and Coatings Tech.,

109(1–3), 391–397 (1998).

56. M. Mehregany, et al., ‘‘Silicon Carbide MEMS for Harsh Environments,’’ Proc. IEEE, 86(8),

1594–1609 (1998).

57. B. Loechel, ‘‘Thick Layer Resists for Surface Micromachining,’’ J. Micromech. Microeng., JUN,

10(2), 108–115 (2000).

58. P. Muralt, ‘‘Piezoelectric Thin Films for MEMS, Integrated Ferroelectrics, 17(1–4), 297–307

(1997).

59. A. A. Ayon, et al., J. Electrochem. Soc., 146, 339 (1999).

60. M. A. Douglas, Trench Etch Process for a Single-Wafer RIE Dry Etch Reactor, August 8, Texas

Instruments Incorporated, 1989.

61. R. B. Gmbh, Germany, patent 42410445C1.

62. M. Madou, Fundamentals of Microfabrication, CRC Press, New York, 1997.

63. J. M. Bustillo, R. T. Howe, and R. S. Muller, ‘‘Surface Micromachining for Microelectrome-

chanical Systems, Proc. IEEE, 86, 1552 (1998).

64. G. T. A. Kovacs, N. I. Maluf, and K. E. Peterson, Proc. IEEE, 86, 1536 (1998).

65. J. Mohr, Sensor Mater., 10, 363 (1998).

66. Y. Yoshino, K. Inoue, and M. Takeuchi, ‘‘Effects of Interface Micro Structure in Crystallization

of ZnO Thin Films Prepared by Radio Frequency Sputtering,’’ Vacuum, 51(4), 601 –609 (1998).

67. J. Yan, J., M. Yoshino, and T. Kuriagawa, ‘‘On the Ductile Machining of Silicon for Micro

Electro Mechanical Systems (MEMS), Opto Electronic and Optical Applications,’’ Mat. Sci. Eng.

A—Structural Materials Properties Microstructure and Process., JAN 15, 297(1–2), 230–234

(2001).

68. V. P. Veiko, ‘‘Laser Microshaping: Fundamentals, Practical Applications, and Future Prospects,’’

RIKEN Rev., 32(Jan), 11–18 (2001).