ECE Semiconductor Device and Material Characterization

Transcription

1 ECE 483 Smiodutor Dvi ad Matrial Charatrizatio Dr. Ala Doolittl Shool of Eltrial ad Comutr Egirig Gorgia Istitut of hology As with all of ths ltur slids, I am idbtd to Dr. Ditr Shrodr from Arizoa Stat Uivrsity for his grous otributios ad frly giv rsours. Most of (>8%) th figurs/slids i this ltur am from Ditr. Som of ths figurs ar oyrightd ad a b foud withi th lass txt, Smiodutor Dvi ad Matrials Charatrizatio. Evry srious miroltrois studt should hav a oy of this book! ECE 483 Dr. Ala Doolittl

2 Dfts ys of Dfts Dft Ethig Gratio Rombiatio Caaita rasits D Lvl rasit Strosoy ECE 483 Dr. Ala Doolittl

3 Dfts ad Yild Mtal Imuritis Itrstitial Oxyg Vaais Slf Itrstitials Rombiatio Ctrs Mtal Priitats Disloatios Stakig Faults Priitats DRAM Rfrsh Failurs Laky Jutios Oxid Brakdow Biolar ras. Pis Yild $ ECE 483 Dr. Ala Doolittl

4 Wafr Dfts Bulk Si Partils, Sraths Eitaxial Si Roughss Mtals Mtals Doats Oxyg COPs Dfts x x Ei Layr Havily Dod Substrat t Dudd Si Priitats Dudd Layr t Priitatd Substrat COPs (Crystal Origiatd Pits) ECE 483 Dr. Ala Doolittl

5 Partils Rsidus Orgais Light Mtals Alkali Mtals,.g., Na Mtals Dft ys Cu*, F*, Cr*, Ni*, Z, Ca, Al (* Most imortat?) Crystal Origiatd Pits (COPs) Surfa Roughss ECE 483 Dr. Ala Doolittl

6 Dft Sours Silio Startig Matrial Silio Growth Wafr Sawig, Polishig Wafr Pakagig, Shiig Wafr Claig Liquids, Gass Oxidatio, Diffusio Photorsist Io Imlatatio Suttr Dositio Pross Equimt Eitaxial Growth Rativ Io Ethig Polymr Cotairs/Pis Door Higs Light Swiths Ball Barigs Pol ECE 483 Dr. Ala Doolittl

7 Poit Dfts ECE 483 Dr. Ala Doolittl

8 Li, Pla, Volum Dfts ECE 483 Dr. Ala Doolittl

9 Stakig Faults Oxidatio-idud SFs: Si itrstitials ar gratd durig oxidatio ad ford ito th substrat SFs a also b gratd at substrat/i itrfas () Si () Si o Viw Oxid Si Si Itrstitials Atom las SF i GaAsN ECE 483 Dr. Ala Doolittl

10 Dft Ethig Crtai ths attak dftiv rgios allowig dft idtifiatio (th ris giv at d of ots) D.C. Millr ad G.A. Rozgoyi, Dft Charatrizatio by Ethig, Otial Mirosoy, ad X-Ray oograhy, i Hadbook o Smiodutors 3 (S.P. Kllr, d.) North-Hollad, Amstrdam, 98, ASM Stadards F47 ad F26, 997 Aual Book of ASM Stadards, Am. So. st. Mat., Wst Coshohok, PA, 997. ECE 483 Dr. Ala Doolittl

11 Dft Ethig Diffrt ths attak dftiv rgios diffrtly Ca b atuatd through or doratio A Dfts - Itrstitials So Wright A Dfts: HFHNO 3 A Dfts: HFHNO 3 H 3 PO 4 D Dfts - Vaais.25 mm So Wright HFHNO 3 HFHNO 3 H 3 PO 4 Mirograhs ourtsy of M.S. Kulkari, MEMC (J. Eltrohm. So. 49, G53, Fb. 22) ECE 483 Dr. Ala Doolittl

12 Dft Eth Rfrs [] E. Sirtl ad A. Adlr, Chromi Aid-Hydrofluori Aid as Sifi Ragts for th Dvlomt of Ethig Pits i Silio, Z. Mtallkd. 52, , Aug. 96. [2] W.C. Dash, Cor Priitatio o Disloatios i Silio, J. Al. Phys. 27, 93-95, Ot. 956; Evid of Disloatio Jogs i Dformd Silio, J. Al. Phys. 29, 75-79, Aril 958. [3] F. So d'aragoa, Disloatio Eth for () Plas i Silio, J. Eltrohm. So. 9, , July 972. [4] D.G. Shimml, Dft Eth for <> Silio Igot Evaluatio, J. Eltrohm. So. 26, , Marh 979; D.G. Shimml ad M.J. Elkid, A Examiatio of th Chmial Staiig of Silio, J. Eltrohm. So. 25, 52-55, Ja [5] M.W. Jkis, A Nw Prfrtial Eth for Dfts i Silio Crystals, J. Eltrohm. So. 24, , May 977. [6] K.H. Yag, A Eth for Dliatio of Dfts i Silio, J. Eltrohm. So. 3, 4-45, May 984. [7] H. Sitr, Itgratioal Ethig Mthods, i Smiodutor Silio/977 (H.R. Huff ad E. Sirtl, ds.), Eltrohm. So., Prito, NJ, 977, [8] K. Graff ad P. Him, Chromium-Fr Eth for Rvalig ad Distiguishig Mtal Cotamiatio Dfts i Silio, J. Eltrohm. So. 4, , Ot [9] M. Ishii, R. Hirao, H. Ka ad A Ito, Eth Pit Obsrvatio of Vry hi {}-GaAs Layr by Molt KOH, Jaa. J. Al. Phys. 5, , Aril 976; for a mor dtaild disussio of GaAs Ethig s D.J. Stirlad ad B.W. Straugha, A Rviw of Ethig ad Dft Charatrisatio of Gallium Arsid Substrat Matrial, hi Solid Films 3, 39-7, Ja [] D..C. Huo, J.D. Wy, M.Y. Fa ad D.P. Witt, IP Eth Pit Morhologis Rvald by Novl HCl-Basd Ethats, J. Eltrohm. So. 36, 84-86, Ju 989. ECE 483 Dr. Ala Doolittl

13 Imuritis or Dfts Shallow-lvl imuritis (doats) - masur otially Photolumis Photoltro strosoy D-lvl imuritis (mtals) - masur ltrially D lvl trasit strosoy (DLS) Nd to dtrmi Imurity dsity, N Imurity rgy lvl, E Catur Cross stio σ Doat E Shallow-lvl Imuritis Si Mtal E E v D-lvl Imuritis ECE 483 Dr. Ala Doolittl

14 Gratio-Rombiatio Cosidr a smiodutor with a d-lvl imurity at rgy E E Eltros ad hols a b aturd ad mittd Catur is haratrizd by th atur offiits & σ v th whr σ is th atur ross stio [m 2 ] ad v th is th thrmal vloity of ltros. Similarly for hols. Emissio is haratrizd by missio rats ad h ltro ( ) ad hol ( ) ouatio is also dd E E C E N E V (a) (b) () (d) x ECE 483 Dr. Ala Doolittl

15 Doors ad Ators G-R trs a b doors or ators h harg stat is : Door: Ator: "" "" "-" "" ECE 483 Dr. Ala Doolittl

16 Carrir Statistis h hag i ltro ad hol dsitis ad is d dt b a G R ( ) ( ) E E C E d dt d G R ( ) ( ) E V (a) (b) () (d) x h hag i tra dsity is d dt d d G R ( )( N ) ( dt dt ) his quatio is diffiult to solv baus, i gral, w do ot kow ad ECE 483 Dr. Ala Doolittl

17 ECE 483 Dr. Ala Doolittl Carrir Statistis Solvig th d /dt quatio givs ( ) t N t t ) / x( ) ( ) / () x( ) ( τ τ τ Now osidr a -ty smiodutor with ltro atur ad missio oly ( ) t N t t ; ) / x( ) / () x( ) ( τ τ τ missio atur

18 Eltro Emissio Simlifyig Assumtios: All G-R trs ar ouid by ltros for t < For t, ltros ar mittd t t ( t) () x( ) N x( ); τ τ τ.8 (t)/n t/τ ECE 483 Dr. Ala Doolittl

19 Eltro Catur Simlifyig Assumtios: All G-R trs ar mty of ltros for t < For t, ltros ar aturd t t t ( t) () x( ) N x( ) N x( ) ; τ τ τ τ.8 (t)/n t/τ ECE 483 Dr. Ala Doolittl

20 ECE 483 Dr. Ala Doolittl Stady Stat W hav assumd that all G-R trs ar ithr omltly ouid by ltros or omltly mty From ) x( ) ( ) () x( ) ( τ τ t N t t N For Stady stat, t For i th sa-harg rgio N For G-R trs i th lowr half of th bad ga, << N tras i th lowr ½ badga td to fill u tra ouay is a wightd avrag of th atur ad missio rats. dltio rgio tra ouay is a wightd avrag of oly th missio rats.

21 Caaita rasit Wh arrirs ar aturd or mittd, th harg hags with tim Ca dtt this by masurig urrt, aaita, or harg Caaita is most ommoly masurd C A qk 2 sε N ( V V ) bi sr N sr is th total harg i th sa-harg rgio iludig both doats ad dfts - - N D (Door) -y N - (Ator) N sr ND N ECE 483 Dr. Ala Doolittl

22 Caaita Emissio rasit h Shottky diod is zro biasd Assum all G-R trs ar filld with ltros h diod is rvrs biasd Eltros ar mittd from th G-R trs V -ty -V -V W N D W W E C E E F E V -V V C C(V) t C C t ECE 483 Dr. Ala Doolittl

23 Caaita Emissio rasit ( ) C t A qk s ( ND ( t )) ( V V ) ( t ) ε qksε N C ; C A 2 N 2 bi D ( V V ) bi D Usually N << N D ( ) C t C ( t ) ( ) C 2ND 2N D t x τ C τ C ( t ) C( t ) ( ) C 2ND C C C t ECE 483 Dr. Ala Doolittl

24 ECE 483 Dr. Ala Doolittl Caaita rasit What iformatio is otaid i th aaita trasit? I thrmal quilibrium d/dt d/dt For E F E, N /2, ( ) N ( ) ( ) ( ) k E E N k E E F i F i x ; x k E E N k E E C C i i ) ( x x N f(e )

25 Caaita rasit h assum o-quilibrium missio ad atur rats rmai qual to thir quilibrium valus: ad ; N C EC E x ; k N V x E E k V N ad dsrib th tra ouay for ltros ad hols ECE 483 Dr. Ala Doolittl

26 Caaita rasit h assum o-quilibrium missio ad atur rats rmai qual to thir quilibrium valus: τ τ x x (( E E ) k ) σ ν x σ K x (( E E ) k ) / 2 N K (( E E ) k ) th σ γ 2 2 3/ 2 (( E E ) k ) γ σ 2 whr K ad K 2 ar tmorary ostats usd i th drivatio whr γ K K x 2 (m /m o ) m -2 s - K -2 is a ostat drivd from th tmratur iddt art of th thrmal vloity ad fftiv dsity of stats. whr N 2πm k 2 2 h 3 2, ν th 3k m 2 ECE 483 Dr. Ala Doolittl

27 Emissio im Costat τ x (( E E ) k ) σ γ 2 τ (s) K 225 K 3 K 25 K 275 K γ.7x 2 m -2 s - K E C -E (V) σ -5 m 2 O a ormaliz this tmratur variatio by lottig l( 2 τ ) istad of l(τ ) ECE 483 Dr. Ala Doolittl

28 Miority Carrir Emissio For majority arrir missio from ator imuritis sr ( t ) ND N ; Nsr ( t ) ND N For miority arrir missio from ator imuritis N sr ( t ) ND; Nsr ( t ) ND N C C N sr N D x(-t/τ )x(- t) x(-t/τ )x(- t) N sr N D -N t N sr N D Majority Carrirs N sr N D -N Miority Carrirs ECE 483 Dr. Ala Doolittl

29 D-Lvl rasit Strosoy (DLS) DLS is a mthod to automat th aaita trasit ( ) C t C 2N ( ) D ( ) t x τ Masur C at t t ad t t 2, th subtrat Caaita (F) C t2 t C C( t ) ( ) C t2 x x 2ND τ τ δ K 28 K 26 K K 24 K K t -.3 5x -4 s δc t 2 K t t 2-3 max s im (s) δc (F) mratur (K) ECE 483 Dr. Ala Doolittl

30 DLS ( ) C t2 t C C( t ) ( ) C t2 x x 2ND τ τ δ τ x (( E E ) k ) σ γ 2 Diffrtiat δc with rst to, st qual to zro ad solv for τ τ,max t l 2 t ( t t ) 2 Now w hav τ,max ad Eah DLS tmratur sa (aks i stra) rsult i oly o missio tim ostat-tmratur air. Svral suh sas ar dd to b lottd i a Arrhius lot ECE 483 Dr. Ala Doolittl

31 DLS lots ar mad for various t /t 2 ratios Dtrmi τ,max ad for ah urv Plot l(τ,max 2 ) vs. / τ 2 x (( E E ) k ) Slo givs E - E ad itrt givs σ 2 ( ) γ σ ( E E ) l τ l γ k ( σ ) DLS δc (F) ms, ms ms, 2 ms 2 ms, 4 ms t 4 ms, t 2 8 ms l(τ 2 ) (K) / (K - ) ECE 483 Dr. Ala Doolittl

32 DLS Si δc max C N 2N D C C δc C max 2N D r r ( r ) ( r ) 8N D δc C max for r 2 r t 2 /t C δc max C C t t 2 t ECE 483 Dr. Ala Doolittl

33 DLS Examl Problm: BV CBO of BJ dgradd from V to 5 V BV CBO ormal at 77 K Ei startig wafrs wr OK Rsistivity drod aftr rossig; 5 Ω-m 5 Ω-m Sarh for fast-diffusig d door imurity DLS ( C) Ruthrford Baksattrig δc E C -.56 V RBS Yild S E C -.35 V Ergy Slium otamiatio from dtrioratig rubbr O-rig i sik ECE 483 Dr. Ala Doolittl

34 DLS Variatios h rimary task of a DLS systm is dtrmi C, τ vs so as to xtrat N, E, ad σ. his goal a b rformd by dirt digitatio ad aalysis of th aaita trasit without goig to th xtrms of usig aalog sigal rossig thiqus DSP or umrial fittig rad offs i tra ssitivity vrsus tra rgy rsolutio xist for all thiqus ad it a b show that rgy rsolutio imrovs as tmratur drass* Aalog sigal rossig thiqus (Boxar, Loki ad orrlatio mthods) a hav xtrmly good tra ssitivity (dttio of N <-6N D ) but td to hav oor rgy rsolutio* DSP basd rossig (FF, LaPla, CMLPM, oit diffrtials ad oliar fittig) td to hav vry high rgy rsolutio (E -E 2 < mv) but oorr tra ssitivity (dttio of N <-2N D )* *W. A. Doolittl, ad A. Rohatgi, "A w figur of mrit ad mthodology for quatitativly dtrmiig dft rsolutio aabilitis i d lvl trasit strosoy aalysis, J. Al. Phys., Vol. 75, No. 9, , May (994) W. A. Doolittl ad A. Rohatgi, "Comariso of Covaria Liar Prditiv Modlig to th Modulatio Futio Mthod for Us i D Lvl rasit Strosoy, J. Al. Phys., Vol. 75, No. 9, , May (994). ECE 483 Dr. Ala Doolittl

35 DLS Variatios σ a masurd dirtly by makig th fillig uls short ough i tim (lss tha th atur tim ostat) to rsult i iomlt fillig of th tra stats (i.. t f <τ C ) ll C ll N () t f C 2N - D τ l( C) SSSSS τ σ v tt τ f ECE 483 Dr. Ala Doolittl

36 DLS Variatios A smigly small but imortat oit: All thrmal masurmts (DLS, Hall, t ) masur th hag i Gibbs fr rgy of a dft. GH-S so G H- S whr H is thaly ad S is troy All otial masurmts (i.. os whr a iitial to fial stat trasitio ours) ar ot fftd by troy (othr tha li broadig) makig thm masur H ot G. Eltrially dtrmid ativatio rgis ar almost always lowr tha otially dtrmid ativatio rgis by a fator S S Adix 5. ad rfrs thri for dtails. ECE 483 Dr. Ala Doolittl

37 Rviw Qustios Nam som ommo dfts i Si wafrs. What do mtalli imuritis do i Si dvis? Nam som dft sours. What ar oit dfts? Nam thr oit dfts. Nam a li dft, a ara dft, ad a volum dft. How do oxidatio-idud stakig faults origiat? What dtrmis th aaita trasit? Whr dos th rgy for thrmal missio om from? Why do miority ad majority arrir missio hav oosit bhavior? What is d lvl trasit strosoy (DLS)? What aramtrs a b dtrmid with DLS? ECE 483 Dr. Ala Doolittl