01240143

8/3/2019 01240143

1/7

JOURNAL OF MICROELECTROMECHANICAL SYSTEMS, VOL. 12, NO. 5, OCTOBER 2003 713

Low-Actuation Voltage RF MEMS Shunt SwitchWith Cold Switching Lifetime of

Seven Billion CyclesRichard Chan, Student Member, IEEE, Robert Lesnick, David Becher, and Milton Feng, Fellow, IEEE

AbstractThis paper investigates the performance and lifetimeof a metal-to-metal shunt RF MEMS switch fabricated on anSIGaAs substrate. The switch is a shunt bridge design that iscompatible with standard microelectronic processing techniques.The RF performance of the switch includes actuation voltages ofless than 15 V, isolation better than 20 dB from 0.25 to 40 GHz,and switching speeds of less than 22 s . Varying the geometryof the switch affects both switching voltage and reliability, andthe tradeoffs are discussed. We have developed a cold switchingtest method to identify the root cause of sticking as a failuremechanism. The switch structure includes separation posts thateliminate sticking failure and has demonstrated lifetimes as highas 7

1 0

9 cold switching cycles. These results show that goodreliability is possible with a metal-to-metal RF MEMS switchoperated with a low actuation voltage. [768]

Index TermsMicrowave switches, reliability, RF MEMS, stic-tion, switch.

I. INTRODUCTION

RF MEMS switches are of interest because of their poten-tial for low-loss, wide bandwidth operation, as they havedemonstrated superior RF characteristics compared to FET and

diode based switches. There are many varieties of RF MEMS

switches. The switch can be in series [1] or in shunt [2] withthe signal path, and coupling can be either capacitive [3] or

metal-to-metal [4]. They are a promising circuit element for re-

configurable circuit applications [5], and their ability to directly

integrate with high-speed electronics makes them a low-cost

solution. There have been several demonstrations of MEMS

switches used in phase shifter circuits [6], [7], and applications

in reconfigurable antennas have been presented [8].

However, most of the RF MEMS switches reported today

need high actuation voltages, usually ranging from 30 to 80

volts, making these switches impractical for mobile wireless

communication as well as reconfigurable circuit applica-

tions. The low actuation voltage operation will facilitate the

direct integration of MEMS switches with current MMICs

Manuscript received October 15, 2001; revised January 15, 2003. The au-thors would like to thank Dr. L. Corey (DARPA/SPO), K. Stamper, and Dr.A. Tewksbury (AFRL/SNDI) for their support under DARPA RECAP ContractF3361599-C-1519, and Dr. J. Mink for his support under NSF ECS 9979292.Subject Editor G. K. Fedder.

R. Chan, R. Lesnick,and D. Becher are with the Department of Electrical andComputer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL61801 USA.

M. Feng is with the Microelectronics Laboratory, Urbana, IL 61801 USA(e-mail: [email protected]).

Digital Object Identifier 10.1109/JMEMS.2003.817889

without adding clumsy voltage up-converter circuitry. The

switch that has been developed at the University of Illinois at

Urbana-Champaign (UIUC) [9][13] is a shunt design with

metal-to-metal contact, and the beam is supported at the four

corners by serpentine springs. The shunt configuration provides

very low insertion loss in the up state and the metal-to-metal

contact has the benefit of an inherently wide-band response.

The serpentine supports are a key part of reducing the actuation

voltage [12][14].

Only three companies and UIUC have reported on thelife testing of RF MEMS technology. Rockwell, HRL, and

Raytheon have reported lifetimes, measured in switching

cycles, and actuation voltages of 1.2 cycles at 85 V,

cycles at 30 V, and cycles at 35 V, respectively. The UIUC

switch design has demonstrated lifetimes as high as 7

cycles with actuation voltages less than 25 V. Switch life

ranging from 1 million to 1 billion cycles is indicative of the

trend toward reliability improvement and the maturity of man-

ufacturable technology. Goldsmith et al. (Raytheon) reported

on the lifetime characterization of capacitive RF MEMS

switches [15]. He has demonstrated an exponential relationship

between lifetime and actuation voltage with lifetimes between

(65 V) and (30 V) switching actuations. Accordingto the results, lifetime improves on the order of a decade for

every 5 to 7 V decrease in applied voltage. To achieve UIUCs

objective of ( ) cycles, an actuation voltage of

less than 12 V is a requirement for RF MEMS switches. Fig. 1

compares UIUCs switch lifetime versus switching voltage to

those reported by Rockwell, HRL, and Raytheon and illustrates

UIUCs lifetime objective with a star [1], [5], [15].

Despite their state-of-the-art performance in insertion loss

and isolation over a wide bandwidth, MEMS switches have two

major problems, namely, sticking and poor power handling. The

elimination of sticking and improved power handling are es-

sential to making RF MEMS switches attractive for low cost,

highly reliable ( cycle) applications for future de-

fense and commercial systems. This work has developed a cold

switching test method to clearly identify the root cause of the

sticking problem and has demonstrated a low-voltage switch

that can achieve 7 cold switching cycles.

II. FABRICATION AND DESIGN

The UIUC RF MEMS switch is based on the well-established

GaAs Ion Implanted MESFET MMIC process. This process

has demonstrated state-of-the-art 0.1 gate MESFETs with

1057-7157/03$17.00 2003 IEEE
http://-/?-http://-/?-http://-/?-http://-/?-http://-/?-http://-/?-http://-/?-http://-/?-http://-/?-http://-/?-http://-/?-http://-/?-http://-/?-http://-/?-http://-/?-http://-/?-http://-/?-http://-/?-http://-/?-http://-/?-http://-/?-http://-/?-http://-/?-http://-/?-http://-/?-http://-/?-http://-/?-http://-/?-http://-/?-http://-/?-http://-/?-http://-/?-

8/3/2019 01240143

2/7

714 JOURNAL OF MICROELECTROMECHANICAL SYSTEMS, VOL. 12, NO. 5, OCTOBER 2003

Fig. 1. Lifetime versus switching voltage from published reports [1], [5], [15].

and . The process flow for the

Balanced-Cantilever RF MEMS switch is shown in Fig. 2. It re-

quires six mask layers, all of which are compatible with estab-

lished GaAs MMIC processes except for the dimple process

step. Since our GaAs MESFET MMIC process is relatively ma-

ture, it was easily modified and optimized to produce a high

yield RF MEMS process and a reliable RF MEMS switch.

The metal-to-metal contact shunt RF MEMS switch exam-

ined here features a metal bridge made entirely of gold that

spans a coplanar waveguide transmission line. Fig. 3 shows an

SEM image of a fabricated device. In the up state, the switch

is suspended 3 above the signal line. In the down state,

the switch is pulled into direct metal-to-metal contact with thesignal line, creating a short circuit from signal to ground. The

electrostatic force that pulls the switch down is provided by a

dc voltage applied to the actuation pads beneath the bridge, and

the restoring force that pulls the switch back into its up position

is provided by the mechanical strength of the cantilevers.

III. LOW-VOLTAGE OPERATION PRINCIPLE

A low actuation voltage is a desirable switch attribute because

it will make it more convenient for a switch to be inserted into

real applications. The pull-in voltage of a mechanical structure

depends on the spring constant of the switch , the gap be-

tween the switch and actuation pad , and the actuation areaas given by (1). This expression is an approximation based on

the assumption that the electrostatic forces on the switch are the

same as those in a parallel plate capacitor [16]. Setting the elec-

trostatic force equal to the restoring force of a mechanical spring

given by Hookes Law leads to the desired result.

(1)

Equation (1) leads to some obvious ideas for reducing the

pull-in voltage. The actuation voltage can be lowered by re-

ducing the spring constant, reducing the gap, or increasing the

Fig. 2. RF MEMS switch process flow.

actuation area. Fig. 4 shows the calculated pull-in voltages as a

function of gap and spring constant for a device with an actua-

tion area of 18 000 . This plot shows the range of gaps and

spring constants that must be achieved for low-voltage opera-

tion. To get actuation voltages that are less than 20 Volts, either

the gap must be kept to about 2 or the effective spring con-

stant of the device must be less than about 2 N/m.

IV. METAL STRESS BOWING AND BRIDGE DIMPLE

One of the difficulties in obtaining the gaps and spring con-

stants necessary for low-voltage actuation comes from residual
http://-/?-http://-/?-http://-/?-http://-/?-http://-/?-http://-/?-http://-/?-http://-/?-

8/3/2019 01240143

3/7

CHAN et al.: LOW-ACTUATION VOLTAGE RF MEMS SHUNT SWITCH 715

Fig. 3. SEM image of a fabricated switch with pad dimensions of 150 m 2 200 m .

Fig. 4. Calculated pull-in voltage as a function of spring constant and gap.

stress in the switch electrode [17]. The gold switch tends to ex-

hibit compressive strain and bows above the surface of the wafer

as seen in the SEM image in Fig. 5. This is problematic be-

cause it causes the gap to be dependent on the spring constant.

A switch with a low spring constant will have a larger gap be-

cause the residual stress causes the bridge to bow more.The dependence of the gap on the spring constant is experi-

mentally quantified in Fig. 6 for a typical device size. The gap

between switch and signal line was measured for devices fab-ricated with identical layouts except for cantilever length. An

increase in cantilever length corresponds to a lower spring con-

stant, and for a cantilever that is 8 wide the gap increases

from 2.1 to 6.3 as the length increases from 90 to 450 .

This shows clearly the tradeoff that exists between the gap and

the spring constant, which must be considered when designing

devices with this process.

A bridge structure that includes a dimple was engineered to

reduce the gap between the switch electrode and signal line,

thereby improving electrical contact. Good contact between the

switch electrode and the signal line is critical for isolation be-

tween the input and output of the MEMS switch. If the switch

Fig. 5. Bowed switch showing a compressively strained film.

Fig. 6. Gap between switch and actuation pad for different cantilever lengths.

does not make contact, the structure will behave like a variable

capacitor, which is not a desirable characteristic when used as

a broadband switch. Here we demonstrate that the stress in the

metalbridge is significant, causing themetalpad to arch over the

signal line. Because the pad arches over the signal line, it may

not make good contact when the actuation voltage is applied, as

shown in Fig. 7(a). Fig. 7(a) depicts the case where the actuation

voltage pulls down the pad, but the pad stops when it contactsthe bumps on the ground plane. To solve this problem the metal

pad itself can be tailored to have a dimple in the center. Fig. 7(b)illustrates this approach. The addition of the dimple improves

contact to the signal line and has the added benefit of reducing

the gap. Fig. 7(c) shows an SEM image of a device fabricated

with a dimpled bridge and raised bumps on the signal line.

It is important to note that the contact problem will still re-

quire significant effort. The switches have good dc performance,

but this only indicates good contact to the signal line. They do

not necessarily have good ground plane contact, as it is chal-

lenging to contact both at once.UIUCs current research focus

is on the optimization of the cantilever and bridge geometries

to lower the actuation voltage from 15 V to 10 V while main-

taining good signal line and ground plane contact. We expect a
http://-/?-http://-/?-

8/3/2019 01240143

4/7


(a)

(b)

(c)

Fig. 7. (a) Illustration of potential contact problem between signal line andswitching pad. (b) Dimple solutions to contact problems. (c) SEM image ofthe dimpled contact region showing the raised contact bumps and the dimpledbridge suspended above.

switch with an actuation voltage of 10 V to achieve the goal of

cycles of operation.

V. RF CHARACTERIZATION AND DYNAMIC TESTING

The RF performance of these switches is measured from zero

to 40 GHz using an HP 8510 C vector network analyzer. The

switch is probed in the up state and down state to obtain the

data shown in Fig. 8(a) and (b) respectively. The insertion loss

in the up state is very low less than 0.1 dB across the fre-

quency band because the switch in this condition is a contin-

uous length of transmission line. In the down state, the isolation

is greater than 20 dB for all frequencies up to 40 GHz, whichindicates that a good electrical short exists between signal and

ground.

The RF data of Fig. 8 is a useful static characterization of the

device, with theswitch held steady in either theup or down state.

In order to obtain information about the dynamic behaviorof the

switch a dynamic test setup is utilized. The dynamic test setup

consists of a function generator that supplies a dc control signal

to the actuation pad and an oscilloscope to measure the output

signal. A square wave is used for the actuation signal and an

amplifier is used to increase the actuation signal to the required

potential. Measurements are done in a vacuum chamber to pre-

vent sticking due to atmospheric humidity.

(a)

(b)

Fig. 8. (a)Insertion loss (S21)and returnloss(S11) inthe upstate.(b)Isolation(S21) and return loss (S11) in the down state.

Fig. 9. Switching data from a 9.4-V switch on the dynamic test system.

Fig. 9 shows data collected from the dynamic measurement

setup. This particular switch is being cycled at 10 Hz with a

switching voltage of 9.4 V. The input signal is a 500 kHz, 2 V

peak-to-peak sine wave. The output signal is the upper trace,

which is clearly modulated by the control signal shown in the

lower trace. Testing thus far has only used input signals with

frequencies up to 500 kHz, but the test station will allow future

modifications to include RF input signals.

8/3/2019 01240143

5/7


Fig. 10. Measured data exhibiting a 21.4 s switching speed.

A close examination of the transition from up state to down

state allows measurement of the switching speed and transition

time. The switching speed is the time between the application

of the actuation signal and the modulation of the output signal,

and the transition time is the time required for the output signalto change from on to off [18]. Fig. 10 shows a device with a

switching speed of 21.4 and a transition time on the order of

1 or 2 with a switching voltage of 15 V.

VI. RELIABILITY: STICKING FAILURE AND SOLUTION

One of the major problems with MEMS switches is a gen-

eral propensity for moving parts to stick together. Parts can

stick during the fabrication process, especially during the re-

lease of sacrificial layers, and they can also stick during opera-

tion. The processing issues can usually be alleviated with min-

imal difficulty, such as the inclusion of a supercritical carbondioxide drying technique as applied in the UIUC process, but

the problem of parts sticking during testing and actual operating

conditions is much more daunting.

Sticking issues are well know in RF MEMS Technology and

there are many suggested causes such as surface roughness,

molecular force, Casimir force and charge force. However, no

clear identification of the cause of sticking has been made.

In order to separate switch failures due to sticking and power

handling, two testing methods termed hot switching and

cold switching were developed. Hot-switching tests consist

of turning on both the input and control signals and monitoring

the output signal on the oscilloscope as seen in Fig. 9. The

control signal is run at up to 5 kHz and the input signal istypically a 1 MHz, 2 V peak-to-peak sine wave. Cold switching

tests are performed by running the control signal with the input

turned off, and then checking periodically to determine if the

switch is still working.

Based on hot andcold testing data, charge accumulationin the

passivation layer causes our switches to stick during operation.

The passivation layer, typically silicon nitride, is used to insu-

late the actuation potential from the switching electrode. These

thin insulating layers are forced to support a large electric field

and repeated contact with the metal bridge when the actuation

potentials are applied, which leads to static charge becoming

trapped within the dielectric. This charge cannot escape because

(a)

(b)

Fig. 11. (a) SEM image of separation posts that eliminate sticking due tocharge accumulation. (b) SEM close-up image of a separation post.

it has no conductive path to ground. Therefore, the charge ac-

cumulates until eventually there is enough to permanently hold

the switch in its actuated position.

UIUCs solution to the sticking problem is a novel designthat prevents the switch electrode from contacting the passiva-

tion layer through the use of strategically positioned separation

posts. This novel design currently has several patents pending

[19]. The posts typically stand about one micron above the di-

electric layer, so when the switch is pulled down it comes to

rest on the posts instead of the dielectric. This gap reduces the

magnitude of the electric field across the dielectric and therefore

reduces any accumulation of charge. This technique has essen-

tially eliminated the problem of sticking and makes it possible

for the switch to be cycled 7 billion times with no observed fail-

ures due to charge accumulation.

When the switch is actuated, the greatest amount of contact

and highest fields occur between the metal bridge and bottomactuation pad. Therefore charge accumulation is most likely

to occur where the bridge contacts the dielectric layer directly

above the bottom actuation pads. By positioning separation

posts at each corner and within the actuation pad, contact

between the suspended metal pad and dielectric is eliminated.

Fig. 11(a) and (b) are SEM images that illustrate the use of

separation posts.

A comparison of the percent of failures due to charge accu-

mulation for switches with and without separation posts clearly

shows that the posts significantly improve the switch lifetime.

The percent of failure for over 170 switches with separation

posts is only 3.4%. Whereas the percent failure is 71.2% for
http://-/?-http://-/?-http://-/?-http://-/?-

8/3/2019 01240143

6/7


Fig. 12. Measured data exhibiting contact deterioration.

an equal number of switches without separation posts, which

were tested specifically to determine how long they can be ac-

tuated without sticking. In addition to these statistics, switches

with separation posts have achieved lifetimes as high as 7

cycles, which are at least three orders of magnitude greater thanthe lifetimes achieved by switches without separation posts.

VII. RELIABILITY: CONTACT DEGRADATION, POWER

HANDLING, AND GEOMETRY OPTIMIZATION

Two dominant switch failure mechanisms, besides charge ac-

cumulation, are contact degradation and deformation caused by

high current flow. The main failure mechanism observed during

hot switch testing is contact degradation resulting in a more re-

sistive path to ground and poor isolation. Fig. 12 shows the data

from a switch that is close to failure. When the failure occurs it

is not an immediate loss of contact, but a rapid deterioration that

occurs over the last few thousand cycles until the input signal isnot modulated at all. This increase in contact resistance may be

due to a change in surface morphology or a buildup of a thin

insulating film on the contact points, but thus far experiments to

isolate the failure mechanism have been inconclusive.

A comparison of the hot and cold switching lifetimes shows

a large difference between the two. Hot switching tests have re-

sulted in lifetimes of 1.6 cycles whereas cold switching

tests have produced lifetimes as high as 7 cycles. The dif-

ference between hot and cold switching lifetimes suggests that

the failures are not a result of the physical stress of switching,

but have to do with the current passing through the contacts.

Efforts to reduce the actuation voltage of switches by opti-

mizing the geometry have some benefits in terms of reliability.Switches that can operate with lower actuation voltages fur-

ther reduce the risk of charge accumulation because the electric

fields across the dielectric are lower, leading to reduced sticking

problems [15]. Low-actuation voltages also require small gaps

between switch and actuation pad, which improves reliability

because the switch does not have to move as far, reducing any

internal stress caused by the motion of the switch. The most re-

liable switches in this experiment tended to be the devices with

shorter cantilevers.

The geometry of the separation posts is also a critical factor

in achieving a low actuation voltage. The separation posts are

positioned underneath the bridge pad and therefore reduce the

area available for the actuation pad. Examination of (1) shows

the pull-in voltage is inversely proportional to the actuation pad

area. Therefore, to achieve low voltage operation, the separation

post area must be minimized to allow for the largest possible ac-

tuation pad area. Out of 276 switches tested, the average actua-

tion voltage is 14.4 V. This data shows that the separation posts

can be used and still achieve low-voltage operation.

VIII. CONCLUSION

A low-voltage metal-to-metal contact shunt RF MEMS

switch has been developed and tested. These devices have

switching speeds of less than 25 and good RF charac-

teristics from dc to 40.25 GHz with an actuation voltage of

15 V. Optimizing the switch geometry has resulted in low

actuation voltages while the incorporation of a bridge dimple

has lead to improved signal line contact. Separation posts

were also employed that essentially eliminate sticking due to

charge accumulation and resulted in switches with lifetimes

of 1.6 hot switching cycles and 7 cold switching

cycles. Metal-to-metal contact degradation and deformationdue to high current flow are the failure mechanisms that

presently limit UIUC switch lifetime rather than sticking,

which indicates great promise for achieving longer switch

lifetimes. These results indicate the high potential of the UIUC

switch as a reliable low-voltage switch.

ACKNOWLEDGMENT

Thanks also to Dr. S. C. Shen for the original design and early

development of the balanced cantilever RF MEMS switch and

to Dr. D. Caruth for his valuable technical discussions.

REFERENCES

[1] D. Hyman, J. Lam, B. Warneke, A. Schmitz, T. Y. Hsu, J. Brown, J.Schaffner, A. Walston, R. Y. Loo, M. Mehregany, and J. Lee, Sur-face-micromachined RF MEMS switches on GaAs substrates, Int. J.

RF Microwave Computer-Aided Eng., vol. 9, pp. 348361, Apr. 1999.[2] J. B. Muldavin and G. M. Rebeiz, High-isolation CPW MEMS shunt

switches-Part 2: Design, IEEE Trans. Microwave Theory Techn, vol.48, pp. 10531056, June 2000.

[3] C. L. Goldsmith, Z. Yao, S. Eshelman, and D. Denniston, Performanceof low-lossRF MEMScapacitive switches,IEEE Microw. Guided Wave

Lett., vol. 8, pp. 269271, Aug. 1998.[4] D. Hyman and M. Mehregany, Contact physics of gold microcontacts

for MEMS switches, IEEE Trans. Components Packaging Technol.,vol. 22, pp. 357364, Sept. 1999.

[5] R. E. Mihailovich, M. Kim, J. B. Hacker, E. A. Sovero, J. Studer, J. A.Higgins, and J. F. DeNatale, MEM relay for reconfigurable rf circuits,

IEEE Microw. Wireless Compon. Lett., vol. 11, pp. 5355, Feb. 2001.

[6] B. Pillans, S. Eshelman, A. Malczewski, J. Ehmke, and C. Goldsmith,X -band RF MEMS phase shifters for phased array applications, IEEE

Microw. Guided Wave Lett., vol. 9, pp. 517519, Dec. 1999.[7] M. Kim, J. B. Hacker, R. E. Mihailovich, andJ. F. DeNatale, A dc-to-40

GHz four-bit RF MEMS true-time delay network, IEEE Microw. Wire-less Compon. Lett., vol. 11, pp. 5658, Feb. 2001.

[8] J. Bernhard, N. W. Chen, R. Clark, M. Feng, C. Liu, P. Mayes, E.Michielssen, and J. Mondal, Mechanically conformal and electroni-cally reconfigurable apertures using low voltage MEMS and flexiblemembranes for space based radar applications, in Proc. IEEE Antennasand Propagation Society International Symposium, 2000, p. 99.

[9] S. C. Shen and M. Feng, Low actuation voltage RF MEMS switcheswith signal frequency from 0.25 GHz to 40 GHz, in IEEE Int. Electron

Device Meetings 1999, Dec. 1999, pp. 689692.[10] S. C. Shen, D. Caruth, and M. Feng, Broadband low actuation voltage

RF MEM switches, in Proc. IEEE 2000 GaAs IC Symposium Digest,Nov. 2000, pp. 161164.
http://-/?-http://-/?-

8/3/2019 01240143

7/7


[11] S. C. Shen, D. Becher, D. Caruth, and M. Feng, Sub-10 volts RF MEMswitches, in Proc. 2001 Government Microcircuit Application Confer-ence Digest of Papers, Mar. 2001, pp. 9497.

[12] S. C. Shen, D. T. Becher, D. C. Caruth, and M. Feng, Development ofbroadband low-voltage RF MEM switches, in Proc. 2001 GaAs MAN-TECH Conference Digest of Papers, May 2001, pp. 8184.

[13] S. C. Shen, D. Becher, Z. Fan, D. Caruth, and M. Feng, Developmentof broadbandlow-voltage RF MEM switches,Active and Passive Elect.Compon., pp. 97111, 2002.

[14] S. P. Pacheco, L. Katehi, and C. Nguyen, Design of low actuationvoltage RF MEMS switch, in Proc. IEEE MTT-S 2000 InternationalMicrowave Symposium Digest, May 2000, pp. 165168.

[15] C. Goldsmith, J. Ehmke, A. Malczewski, B. Pillans, S. Eshelman, Z.Yao, J. Brank, and M. Eberly, Lifetime characterization of capacitiveRF MEMS switches, in Proc. IEEE MTT-S 2001 International Mi-crowave Symposium Digest, May 2001, pp. 227230.

[16] G. Kovacs, Micromachined Transducers Sourcebook. Boston, MA:McGraw-Hill, 1998.

[17] E. Obermeier, Mechanical and thermophysical properties of thin filmmaterials for MEMS: Techniques and devices, in Proc. Mat. Res. Soc.Symposium, vol. 444, 1997, pp. 3957.

[18] H. J. De Los Santos, Y. H. Kao, A. L. Caigoy, and E. D. Ditmars, Mi-crowave and mechanical considerations in the design of MEM switchesfor aerospace applications, in Proc. IEEE Aerospace Conference, vol.3, Feb. 1997, pp. 235254.

[19] M. Feng, D. Becher, N. Holonyak Jr., R. Chan, S. Shen, and University

of Illinois at Urbana-Champaign, Low Voltage High Cycle RF MEMSDevice, File no. 1210.666 12, July 11th, 2002.

Richard Chan (S02) received the B.S. (withhighest honors) and the M.S. degrees in electricalengineering from the University of Illinois atUrbana-Champaign (UIUC), in 2001 and 2002,respectively. He is currently pursuing the Ph.D.degree in electrical engineering.

From 2001 to present, he is a member of the HighSpeedIntegrated Circuit research group at UIUC. Hisresearch interests include fabrication and characteri-zationof lowvoltage broadband RF MEMSswitches,large signal modeling of InP submicron heterojunc-

tion bipolar transistors(HBT), and broadband MonolithicMicrowave IntegratedCircuit (MMIC) design using SiGe and InP HBTs.Mr. Chan is a recipient of the John Bardeen Fellowship in 2001, Yunni Pao

Fellowship in 2002, and Intel Foundation Ph.D. Fellowship in 2003. He is aMember of the Eta Kappa Nu and Tau Beta Pi Engineering Honor Societies.

Robert Lesnick received theB.S. degreein electricalengineeringfromthe Uni-versity of Virginia, Charlottesville, graduating with highest distinction in 2001and the M.S.E.E. degree from the University of Illinois at Urbana-Champaign(UIUC) in 2002.

He is a Naval Reactors Engineer for the Naval Nuclear Propulsion Programwith the responsibility to design, build, operate, maintain, and manage the nu-clear powered war ships and facilities that support the U.S. Navy nuclear-pow-ered naval fleet. As a member of the High Speed Integrated Circuits Group atUIUC, he conducted research on the fabrication and characterization of low-

voltage broadband RF MEMS switches.Mr. Lesnick is a recipient of the William L. Everitt Award for Excellence inElectrical and Computer Engineering, the Louis S. Ehrich, Jr. Scholarship, thesociety of American Military Engineers Scholarship, the Armed Forces Com-munications and Electronics Award, and the American Society of Naval Engi-neers Scholarship.

David Becher received the B.S. degree with honors in electrical engineeringfrom the University of Nebraska-Lincoln in December 1996. He attended grad-uate school at the University of Illinois at Urbana-Champaign, receiving theM.S.E.E. degree in 1998 and Ph.D. in 2002.

His research focused on high-speed compound semiconductor electronics,particularly ion-implanted GaAs MESFETs, AlGaNGaN HEMTs, and RFMEMS switches. He is currently employed at Intel, Portland, OR.

Milton Feng (SM82F92) received the Ph.D. degree in electrical engineeringfrom the University of Illinois, Urbana-Champaign, in 1979.

From 1979 to 1983, he wasSection Head of theMaterial andDevice Group atTorrance Research Center, Hughes Aircraft Company, Torrance, CA. In 1984,he joined Ford Microelectronics, Inc., Colorado Springs, CO, where he wasthe director of advanced development and fabrication for both digital and mi-crowave/millimeter-wave development programs and for manufacturing tech-nology. Since 1991, he has been a Professor of Electrical and Computer En-gineering and a member of the faculty of the Center for Compound Semicon-ductor Microelectronics, University of Illinois Urbana-Champaign (UIUC). Hisresearch interests include ion-implantation technology in IIIV te chnology, op-toelectronic ICs, ultrahigh-speed analog-digital HBT ICs, and microwave/mil-limeter-wave ICs on material, device, processing, design, and testing.

Dr. Feng received the IEEE David Sarnoff Award in 1997. He received theFY2000 Outstanding Research Award from Dr. Pan Wen Yuan Foundation forthe outstanding contribution of noise reduction in microelectronics. He wasnamed the first Nick Holonyak, Jr., Professor of Electrical and Computer Engi-neering at UIUC in 2000.

Documents

01240143