III-Vs REVIEW THE ADVANCED SEMICONDUCTOR MAGAZINE VOL 18 - NO 6 - AUGUST 20058

Technology: MicroelectronicsNews Update

Engineers at the University ofArkansas have been asked, bythe federal government, to devel-op purely electronic systems, tomake the nation’s power gridmore reliable and efficient.

Silicon-carbide, solid-state equip-ment will replace the electro-mechanical devices like thosethat failed to localise the 2003blackout in the Northeast US,the largest and most catastro-phic power failure in the historyof the country.

“We have to limit potentially cat-astrophic events so that peopledon’t get hurt and equipmentdoesn’t get destroyed,” said AlanMantooth, UA professor of elec-trical engineering and directorof the newly formed NationalCenter for Reliable ElectricPower Transmission.“Theseevents can also severely damagethe nation’s economy andthreaten national security.”

Mantooth and three other UAelectrical engineeringresearchers, Juan Balda, FredBarlow and Aicha Elshabini,received $1m from the USDepartment of Energy’sGridWorks Initiative to createand operate the new nationalcenter.

The center’s researchers, includ-ing faculty and graduate stu-dents, will design, test and pack-age the electronic systems forfuture commercial use in thenation’s power grid. Researchersat the University of Wisconsin-Madison, University ofTennessee,Virginia Tech andGeorgia Tech received fundingfor similar research.

Mantooth said governmentleaders chose the UA teambecause of the researchers’expertise in advanced powerelectronics and longtime inves-tigation of SiC, a more durableand faster semiconductor thanmaterials currently used in thepower grid.

For the past decade, UA electri-cal engineers have developedand packaged SiC systems for NASA and the defense industry.The UA team was oneof the first to investigate thematerial’s application to powertechnology.

Mantooth said SiC is a superiormaterial for several reasonsother than its strength and abili-ty to respond quickly to powerinterruptions. Its propertiesallow an extremely high voltage

capability. It is also a good thermal conductor, operating atvery high temperatures anddoes not require extra equip-ment to remove heat. Mantoothemphasised that this quality canreduce overall mass and volumeon a power grid.

For the national power transmis-sion center, researchers will cre-ate mathematical models of SiCdevices to simulate the design oflarge systems.Those will then berigorously tested and packaged.Packaging involves creating pro-tective coatings and enclosuresto prevent the material frombreaking down, when subjectedto high voltages and currentsand when interacting with airand water.

Mantooth said the 2003 black-out, that caused billions of dol-lars in lost revenues and wastriggered by fallen branchesbecause of a storm, should havebeen limited to a local area inOhio.

The fallen trees caused hugesurges of current, whichmechanical devices known asfault-current limiters shouldhave squelched, or grounded,to prevent the surges from

travelling beyond the localarea. However, these mechani-cal switches did not functionquickly or properly, and creat-ed a cascading effect, or chainreaction of blackouts. Evenwith electro-mechanicalswitches functioning properly,the entire process is too slow,Mantooth said.

“It actually happens in the blinkof an eye, but it’s not as fast as acomputer,” said Mantooth.“Wewant to get the electric systemof our country able to react likea computer can react -- at elec-trical speeds, not mechanicalspeeds.

“The catastrophe of the black-out in the Northeast wasn’t thetrees that fell on the power linesin Ohio. It was the cascadingeffect. None of the built-in pro-tection devices reacted quicklyenough or properly to limit theproblem to a local level.And soyou have the entire Northeastgrid in disarray.

“That’s a reliability problem, andyou just can’t have such things.What you need is faster-acting,more-reliable, purely electricalsystems, what we refer to assolid-state solutions.”

Boost for SiC in power grid systems

Bede has delivered a

BedeMetrix-F automated in line

X-Ray metrology tool at the

Fraunhofer Centre Nano-elec-

tronic Technologies (CNT) in

Dresden, Germany.

CNT, a public private partner-

ship of AMD, Infineon and the

Fraunhofer Gesellschaft will

use the BedeMetrix-F to devel-

op and control advanced semi-

conductor manufacturing

processes at a new state-of-the

art facility currently being built

in Dresden.

Dr Peter Kuecher, who piloted

Infineon’s 300mm wafer yields,

and is head of CNT said,“AMD,

Infineon and the Fraunhofer

Gesellschaft identified Bede as

a leader in X-Ray metrology

tools for semiconductor manu-

facturing, with a growing

installed base at major manu-

facturers worldwide.

“The BedMetrix-F meets

metrology needs of the majori-

ty of current and future materi-

als and technologies on the

ITRS roadmap.’’

Dr Neil Loxley, CEO for Bede

added,“We are excited to be

working with CNT to develop

applications for X-ray metrolo-

gy as the European industry

transitions to the 90nm and

65nm technology nodes. I

believe that the relationship

between Bede and CNT will

further develop the applica-

tions for X-ray metrology in

advanced semiconductor

manufacturing, and help Bede

remain as the leading global

provider of X-ray metrology

solutions.”

Web: http://www.bede.co.uk

Bede wins into CNT, Dresden

Dresden