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. REPORT DOCUMENTATION PAGE AFRL-SR-AR-TRAS- SORT q RRC USE ORY TBO OE 15 May 2002-4 Atay 2003 PINAL WEE ANS ROTI WEG HOREERS iceovishu-ge Devices ane Arrays: Quersua aad Cubsrene elf sad Opt os tectranie DevzeTtegratian asec. Prot Las PERF ORTON WENT HOPES UNIVERSITY OF ILLINOIS GRANTS AND CONTRACTS OFFICE a9 com 40 bow s WRIGHT STRFFT ATERTION HAMUAICH (61890 6612 SFOSRINE als WILSON BLVD sure ARLINGTON VA 22205 FORD 0972 [71 80pscSmTTARY OTE DISTRIBCTION STATEMEN1 A: Vvtested Dang is roa, sys aie avnces eve eon end inte ushnolugyof Li aly of puna vio, hg ae ‘ON SPRARATE SHEET" PE MOEN OPERCES—| ferenercoer———] Fr SEDURTTY REET] TO EEGURITY ASTI TOW [10 SSSURITY ESTER TISTATON OF RASTA] Crssiod Uncassied Voetaited w. ee ER occas 1. the discovery thal microdischarge devices with Si pyramid cuthmies are ctruordinarily aensicive photodereetors i the near-IR and visihle. This new hybrid semiconductoriplasna devico was found lo have 4 photoresponsivity at Icast wonder of ‘magnitude greatcr tan thal of cormmercially-swvalable avalancie photodiodes and two coders of magaituc lacyer than Ike respxnse of conventional Si photodiodes 2. Gain ona bloc (460.30 1m) transom of singly-chargod Xs has boca observed in a Segmented, inoar aay of mnicralischarges, Cbricated ina covarsis malilaysr sructore having an active length of 74 om. This isthe fst cxampte of a mieradischarpetriven optical amplifier, 3, The firs, lange arags of mictodiselimges hive been fabricated and characterized. Nine Jrundced (900) pixels have bocn integrate inua 8S rm? of Si, which concsponds to 104 pixels-een-2, An order af miegnimde increase inthis packing densily shold he feasible, The eifcal innovation (Yvick?) co making rays larger han 295 x 5 woh is the design ofthe dilectric 4 Array ws large as 15 x 13 pliefs in coranaie stustores have hcen achieved by individually ballasting each pixcl with fxegrated Chick film resistors. Much lager arrays are undocbtcdly feasible, 5. Devicas having dimensions and volur have born operate successfully 6, An array uf mierosischarges has been stiown to significanly deurease the starting vollege fe an are lamp, addressing a major cemern ofthe Tightiny industry 7. Eight patent applicatious ave boon fed with ‘he US. Pateac and ‘Trademark Office and the claims for suet erpulent have been granted by the Exanciner. A siall company sarted several years uge hy two of Dr, Eden's PLD, students ta comrsercilize rmicrodiwharge technoloay is (among othor thinys) developing instounents for Arnold AFB (Tennessee) and ‘Tyndall AFB (lores) under to contracts, as seal as (10 man)2 ad 10 aL respeetively, Fina Tecnyivat, REPORT. on AFOSR Grant No. F49620-00-1.0372 “Microdischarge Devices and Arays” Dr. Thaward R. Schlossberg ‘Disestovate for Hlectouivs und Phyvicn US, Air Baroe Oifice of Scientific Researoh ‘AFOSIUNE 4015 Wilson Blvd., Roomn 713 ‘sclington, VA. 22203 DISTRIBUTION STATEMENT A. ‘Approved for Public Release Distributian Unlimited Ereparcd by TG. Bea University of Utinois [Department of Flectrical and Compotcr Euginesting, 1406 W. Crean 8 Urbana, ML 61801 200503522 407 Jonuary 2005 “Taner Contras ‘A. MicroplasmaScmiconducear Phouetectans B. Large Si Device Arrays. ~ ©. Cerumic Planar Arrays With lndividuslly-Ballasted Pines D. Tineur Ceramic Amays: Patfoum for Microchip Lasers. E. Other Recont Results: Hexdble Displays, Ceramic Dielectrics, 40 pan DRIE Devices, Sommary Roforenec. UL, Papers Published Under AKOSR Suppott (2000-2003), TIL Panis Grented Under AFOSR Support (2000-2003) TY, Graduate Sandents ané Postdoctoral Researchers Supported Degrest Granted. SeouRY ‘Under the support of AFOSR grant no, F49620 OD 1 0372, we have heen pursuing the ropertes and applications of wsicradiaclange devices having spaial dimensions in dhe 10-100 ten renge. During this greet, several major advances have been mate inte technotogy of this neve rity of photeni: devices. Highlights include: 1, ‘The discovery thar nierdischarge devices with Si pyramid eathodes are exttaordinaily sensitive photodetectors in the peur JR an visible, This ue hybrid semicondustoripasma device was food to have a photocesponsivity af Just an order of magaitade greater than that ‘of commoerallyswailable avalanche photodiodes and two orden: of magnitude larger tha the response of conventional Si photodiodes. 2. Gain on a be (460.30 nm) transition of wingly-changed Xe hax bees observed in a segmented, linear aay of mniexediscbarges, fabiicated in a cocamic multilayer suucure having an active engdh of ~1 em, This isthe First exanple of a microdischerge ceiver, optical amplifier. 3. ‘The first nage azays of micmodischarges have beee fabricated and charsctatized, Nine fbontved (900) pixels have been iteyratal inta 8.5 mm* of Si, which corresponds to >10" pinels-cm An onder of magnitude increase inthis packing density shouldbe feasible, The ‘sitcal innovation (“tick”) to making uray larger than ~S 5 work is he design of the loot. AL Arrays as large ag 13 > 13 pixels in ceramic stuceures have beca achicved by individoaly Dallasting cach pixel with integrated chick flm esistrs, Much larger arrays are ondontuedly feasible, 5. Deeviecs baving dimensions und volumes us anal s (10 pa and 20 a, respectively, bave been operated succesefully An amay of mictodischonges hus boom shown to significantly decrease the starting voltage far amare lomp, addressing a major concern of the lighting indasty. ight parent opyilizations have bora filed with the U.S, Patent and Trademerk Office and te claims for another patent have been granted by the Examiner. A sta‘l company stated several yours nisi by lwo of Dr. Hdew’s Ph.D. studenls to commercialize microiwharge Aechnology is (among other things) developing. instrament for Amold AF CTennosere) and ‘Tyndall AEB (Hlorida) under ton eomtracte, ‘these are obfy a few of the accomplishments relized thus fac undec this AFOSR. geaut Incorporating carbon nanotubes into microdischarge devices, excitation af phosphors With srrays, and the domuoneteation of ready momufuctursblo, flexible aeays have also boon achieved: Mager Accompastamenrs Uyer AFOSR Gans F9620-00-1-0372 A. Microplasma/Semivonductor Photadetactors ‘We recently obsorved thar mictodischarge devices in Si exhibit considerble Photosensitivity im the visible and near-infeared TR). Dotted mensnrsments made aver the ‘course ofa year with micsndischarge devices having ieverted square pyroraidal ewhodes show convincingly that this new hybrid semiconductorfplasma asundeteetor i, im fact, emsideraby more eensitive than a Si avalanche phavadinde (APD). Figure 1 hows the spectral response (expressed in A.W 3 for a 100 yma square ‘Pévamidal Si miorocavity operating in 400 Toma Ne. The di cetchable polyimide film (-8 en). For comparison, the sensitivity of a commercialy-available (Bemamatsu $2381} APD, having a gaén up to 100, i this apsoinl region is eso ihusrated. ‘Although the spectial profile of the microdischarge respoute ie guile similar to that fr the Si Iosuic consists of SiO, sna u dry ADD. the absolute esponsivity ofthe microdischarge excrsis that forthe St device by mre tan order of magitude, ‘Data similas to thewe of Fig 1 bot fora (50 pi? mieradischange devioe are preset ig. 2 fora Ne pressure of 890 Tore. Because of is smaller dimen scaling, this dovice prefers to operate at higher prossoves. Novi thatthe ea repose or is vice (-10P A/W) Is almost 355 higher thn that forthe larger (100 100m? device and that ‘taxiraur sensitivity has moved from the nesr-TR 1 the rod (2 ~620 am we wnd the impact ot pez Agra 8 py iO, ep jo woermdiney “1 Bi MOBN OL OOP “(euomorndd 9 zamusernuem) 00) 5 4) eornap afamypsipamsy easnbs Unt G97 830 Ay (uuu) UBuapearyy On. 008 00s on” 008 00gL OOLF 0001 006 008 OoL=uleD . adv !s F . . Jo au 2 . rol ° e ¥ § e z g r — oF A oot 2 “ a aojaeq E r(ur ooL) 4 0004 bee L asuiodsoy yenoodg “ssop.ap (amt opt} pu (unt 9g) a4 J0 SoNDOASSH ai Saree {ASU UL, “GEL, OOS = MA) cONAOp eRe TF OF wJOp In T Be OU IMS BIBL ZBL NOL 008 "A222 (Wu) UZBUEPARAA, o0zt oot 008 009 oor = T T T 0 [ j ie “4 002 7 a] r ! ° 40 BR et fi 8 l I * & r | joe F DOZL 000+ 008-9080 R= = : < L ; ! 1 soo = Lo RGA. = i s I -| coor c fl Fj 00%) (aan og) : esuodsoy pensods ‘Wo interpret the high responsivites of thece hybeld semiconductonfplagm devices int terns of the combined action of s photocathode and the plasma —- spccfically, the effect of enhanced phataelecirm emisvion ue cathade surface in concert sith electcon avalanche, Pretiminury cesolts of nomerice simualions ofthese devices indicate tha: th electric field slreagtt the photosuthode surface during normal operation are enoraoue — 100-400 KY a7, Consoquen‘ly, itis likely that photogencrated electrons are able to vane] directty throught the vacvom baric into the plasms, Once fice of the semiconductor, Phoweloctnms ure reply agcelorared undsr the influcace of the stiang electric field inthe cathode fll and are reprodcved ‘by impact fonization and subsequent avalancte. ‘These considerations and the date of Figs. 1 and 2 strongly suggest that tho response of the device is devenmined psimarly by che Si photocathode and dhe plasma is, 4 a first ‘approximation, wansparcnt. Atvery high plasma power loadings (such as that prosent For the (60 yam}? data of Fag, 23 he opacity ofthe plasmin ses and we believe the sii the wavelength of peak response from tho near-IR tothe rd to be the revlt of trang Ne crnsitions of the pasa co. longer be ignored. Tn shor, Si miorodischanges represent a new and very interesting photodetector concept “The device resenbles n pholomuliplier execpt thut fhe convontionel dymode chain hos been ‘replaced by alow tempersture plasma functioning at atmospheric prewtare. Since the {nthe ~620 nm son, Thus, the opti properti hoteresponse ix determined primarily by the-photecalhuse, see sme plimntie Tha de opevating range of this device can bs extended into the IR and deep-U¥ with the proper chice af semicuaducter photoeatho. B. Large Si Device. ‘Because of the prospect for integration wih electronic devies and subsystims, i-baeod rmicrodischange devices ad arays are of pasticular intesest. Under this AFOSR grant, we have employed photolithographic and conventional wt and dry ctcing tectiques te produce large und previnely defined snrays, Mon of the wok ts date bas centered om micradichore devices shaving invested squase psramidaleathodes for anodes). Developed several years ago, ato with AFOSR support, the inverted pyramid devices have proven tobe reise and an exaustive ‘eeractesizavion of Un eectival and optical propertien over the past 2¢ yes tas resulted in considetabe impro ements in their Bietimes and outpat power. “The soevess of the arrays to be desrihed later wan crtically-dependent upon the dislectis chose. or the device.™* Bast inverted pyramidal Si devi cathode. and an 8 ja thick film ofa dy etchable polyimide having a dielecuic constant €,=29, The VAchacactesstice for these devices exhibited high diffecntial resistivities (-200 M2) an, not sumprimely, sroys larger than 6 x 6 could nt be ignited. However, consisted of the Si introdiacing into the diclctric a thin flm ofa wistevial bavi &, > 5 wa found to have a ckematic {mpuct onthe statilty of ingle devices and arrays, Hor example, Fig. 3 shows a photograph (eft) mad SEMs of 2 30% 3 array of 50 um square microdischange device pixels." Comprising four 15 X15 subaays excited independently of one another the srzay structure asm area of 4.5 mm which cosresponds toa device packing density >1¢" en", Each mictodiscarge piss) hts a mullicomponeat dicletic* consisting of ~0.9 yim SiO, “0.5 im SiN, aad ttn of polyimide, A numbcr of tests prformed on theso davies indicate thatthe s:icon-nitrde itr i anost responsible for the observed stabilization of te devices A photograph ofthe 30% 30 array operaing in 409 Torr of Nes shown in Fig. 4, The {ge igition vattage indicated on the figure (1130 V) is atrifmtable tothe ecsstivity of the Si substrate and does aot, by any meas, representa lower fundamental limit, Ln fact, most ares studied to dtc have operating voltages of only foxr hmndred volts. ‘The vight-hand parton cof Fig 4 ina photageoph othe righ green fuoneavence praduced wien a phosphor (n:2n,8i0,}, nated ontna thin sapphire substrate, is hack-Mhucinated by a 30 % 20 auray ‘operating ith 8500 Tow Ne!50 Torr Xe gas mixture, The gen paver radiated into a solid angle of 5 10° ar was measured to be 14 W und Us emission is quite Ds ‘iewed ftom a dstunue oi several mets Further improvement in the spatial matory ofthe emission produced by these large array is clenly necessary (Fig. 4, left) and tis subjeecis being pursued further under & subcontract to this laboratory ftom Ewing Technology Associates which received an SBIR Phase IM contecct from AFOSR. The goal ofthe SBIR work i iv demonstrate arrays having 1010? pixels and producing hundreds of mW inthe UY. Tt shouldbe emphasized, however, tat the foundation of realizing Inge microdischarge arrays, wae uid with the support of AFOSR granc 1F49620-00-1-0872 and on the basis of our experience vith Wesestractures, we ae confident that sealed, lightreght esrays dsiven at Hine vollage ave feasible even when .Ceramte Tatil “hvexlabralion wil he Moon Solid Slae Technology Labwatury in Teepe, AZ, We have boeo staying microdischarge devices fabricated in muldlayer ceramic suctaes. Ceramic is ofinterea ol only because of ts robust thermal nd mechanical properties (nd, fence, resistance to aggrssie cherie environments) but saa because of We enormous investment lready mote by indy in Tosser erie erie (TCC) welugy ‘Oar inal microdiochurge devices in ueramie mulilyersroctre had interleaviog slectades and microcavities that wete deilled mechanically whi the structure was stil inthe “groon” (Le. preted state. Although these devices id operat i are gas prssures upto and llasted Pixel