10:30am-I 0:45am WP1

A Nuvcl Silicoii Klectro-Optic Device for Sensor Applications

P. LeMirili*, N. Akil, 11. W;illinga, P. 11. Woerlee, A. van dcii Hcrg, ;iid J. l lo l le tna i~ MESA' I<esearcli Institute, IJriivcrsity of Twerite, PO. LIox 2 I 750(1 AI7 Eiischcde, t l~c Nctlicrlands

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liitrocloction Though 11. Newman L I ] reported the ;rvalatiche breakdown liglil cniission in coiivcntional pii junction diode half a century ago, there iirc aliiiust iin successful applications of this plienoiiiciioti iii iitdiistiy. 111 this paper, we report tlic realization of ii ouvcl silicoti clcctro-optic dcvicc, explicitly the integriitioii OS diode aiitifiisc and photodetector, mil the tirst impurtaiit results. 'She diudc aiitifiisc (called antifusc to thc rest c i f this cuntributiuii) resembles a conventional diode but lias a s i i ~ a l l size of a few tens of ri;inomctcrs, wliich pcriiiits easy collcctiuii of all ctnittcd photons. We have reported the antifiise device inudclitig elsewhcrc [?I. 1)cvice Pabricatiun& Measiirciiierii The device fiibricatio~i ciiiployed ii six-inask CMOS cunipatiblc pruccss (Fig. 4). I h t , photodiodc detector windows were iiindc on wtypc silicoii wafer Iiy iiiqilaiitatiun of boron. The antifuse capaciturs, with two oppositely doped poly-Si electrodes aiid ii 6 iini hick LI'CVI) oxide, having dimensions of I0x 10 pi?, wcrc then deposited on tup of this detector window. Tlic ;~iitifiisc is ci.catcd by curitrolled oxide tmxikdown bctwccn tlic two electrodes. The antifiisc a id detector itre electrically sepmitcd Ily a 100 iiin and 700 iiiii thick thcrnial uxidc. 'i'lic pliotudiode window wiis coiiiparativcly lar,gc to collcct all tlic photons coming downwards. Upoti tlie oxide brcakdowii, prog'ainniing cnrrcnts up to 8 inA were applied to fi1rm high qiiiility antifiiscs, which cliaractcristic is shown on Fig. 5. This g q h indicates the o i iwt nflrrcakdowri voltage at approxiiixitcly 3.5 V and iin aiv:il;mchc ciiment o f I inA at 8 V. The series resistance arises froin the sprcadiiig rcsistaucc of the iiiitifiise, fruiri tlic thin film mti i rc of both clcctrodcs. ' I l ic detector is iiii abrupt p i junction opcratcd in the pliotodiodc rcgimc. Efficieiicy To deninnstrate the antitiise light emitting power, we depusitcil ii 0.85 pin thick positive photoresist (Oil. 907/12-deco11iposition energy 100 inJIcin2) oii top of the device. l 'his layer is spccitic;illy sciisitivc to photoiis with ciicrgy larger than 2.75 cV (450 nm). 'l'lic iiust-cxposcil photoresist :ircir w a s developed according io standard process ;oid p1intogr;iplicd in Fig. I . 'I'Iic time dcpciidciicc fckitnrc sixc is plotted in I'ig. 2. The ciiiittcd power, a s c;ilciilatcd, is r~unghly 0.25 W/cii?. 111 Fig. 3, ii incasured spectrum and its iibsurptiun curracted mic arc stiowii io mean that the liglit power iri tlic visible range is ui.dci.s of niagnitiidc larger tlian that i t i tlic neiu UV rcgiuri. The biggest ubstaclc that IiindcIs the dcvclupiiicnt o f iritcgr;itcd optoclectrunics o n silicuii is t l x intcgriition of an efficient light eiiiitter. The convciitional ;~val;irichc hreakdowii light ciiiissiuri qiiantuin etticiciicy is ;ibuni 7 ~ 1 0 . ~ 131 to 6 . 5 ~ IW' 141. l'hcsc low tigores coine nul urily f?unr the light cniitting iticchanisni itscltbiit also tlic nori-r;idiativc currciit loss to tlic large p1an;ir iireii of the juiictiuii, tlic nicasnicnicnt setup c;ipabilitics.. . Tlic nanosc;ilc size diudc-antifiisc light ciiiittc,. JZ on-cliip intcgr;itcd ilctcctui iii 0111' st i iictiirc, iis expected, would Irclp solving tlicsc ~iruhlctiis. In Viz. 6, ihc ~~l i~ i tucur~~ei i t s nf tlic detcctiir iirc sltowii ai difiic~ciit light miiiiirlg currents of t lx anti-fuse. 'l'ltc pliiitociimxd iiie~~eascs liriciirly with thc iticrciisc o t the aritifiisc ~ " S D bias current (Fig. 7), wliicli is in agiceinciit with rcicrcncc [SI. The precise ctticiericy uf this systciii rcqiiircd viiliics of qiiuiiuin dticiciicy of both the omitier ;ind the dctectoi.. A inore pr;icticel iiiiIic;itiori is t ~ i c uvcraII electrical cfficiciicy of this systoni, which is ruugIiiy I IOf. This v;i~iic is about oi ie or.ilcr of magnitude largc~ than the oiic reported i i i rcfcrcricc [hj, iiiid sirriult~iircoiisly ioiplics inucli liiglicr c ~ u a i i t i i ~ n cfficicncy tliiiii the viiliics iiicritioncd i i i [ 3 I, [d]. Ciiiicliisioii A new rnunulithic clcctso -uptiCiil dcvitic h a s I~ccii dcoionsti~alcd. l ' l i c dcvicc is bkiscd on :i lighl emitting iliodc mitifiisc i d pliut~~ilctcciur integrated 1111 ii single silicuii water by CMOS tcclitrul~igy. 'Ilic high efficiency of such a systciu indic:iics ii very iuipori;itit improvcnicnt Ibr the rc;iIi~iitiuii of silicou iiploclcctronic dcviccs. Refweiice [I]. I<. Newmiin, " Visilrlc liglii fiow a silicwi piijniictinii', I'liys. Rev., Vol. 100, nr. 2, pp. 700701,1905. 121. N. Akil et d. "Modcliiig u f light cinissioii spcct~'a iiic;isurctl oii silicoii rranuiictor;calc diutllrantifiiscs", to iippeiir on .. - .. j. ;if Appl, Phys., Aug 2000. [3]. A. G. Chyiiowuth et al., " Photuii cinissioii Iioii~ av;il;irichc hreiikdowii iii silicon", I'hy.Rci,., Vul. 102, iir. 2, pp. 169 376,1956. [4]. J. Kratncr et al., " Light crnillirig dcvices i t i industrid CMOS tcchiiulogy, Scri.W Actiui. A, Vol. 17-38, pp. 527-531, 1993. [SI. V. I:. Iloiitsina et al., '' Light ciiiissiuri froin silicuir iiiiiioiiictOnciilc diudoaiitifiises" I'roc. ottlic tiit. Coiif. ori Appl. of I'hototi. Tcch. (ICAPT), pp. 209213, Joly 1998 [61. K. Misiakos et til., "Moiiolitliic integmtiori of light emitting diudes, detcctors and uptical fibers oii ii silicun wafer: a CMOS cunipatiblc optical sciisu?, IE1)M l'ccliiiicitl Iligcst, 1998

0-7803-5947-X/00/$10.00@2000 IEEE 523

Fig. 1. Developed spot in the phuturesist (t=lOniin, I,=lmA)

a C . U

.* e 0.1

- Y -

0.01

z

d 1 ob0 2 n b 0 30b0

Time [sec]

Pig. 2. Time dependence of the photoresist featurc size

-

Measured spectrum ____ - - 300 nm poly-si

Ahsorption correction

I-

I ------> I

. n. 1E-31 r . , . , . , , ,

8 7 6 5 4 Wavelength [O Ipm]

Fig. 3. Spectrsl photoresist sensitive wavelengths

0 Slhcon(sub) 2 Pdysdicon U Owde

a Silicon (P-type) 1 Polysilicon - Antilure

Pig. 4. Device schematic illustratiun

Vig. 5. Light eniitting diode antifuse current vultage charactcristic

4.0n

- d

-2.on

5 8 4 0.0 U L

2.0n E

I

Fig. 6. Photocurrents passing photodiodes

503.0~ 1.0n1 1.5m 2.0m 2.5m

Antiuse currents [A]

Pig. 7. Linear dependence between photodetector currents and antifuse lighi emitting currents

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