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Jurnal f the Krean Ceramic Sciety Vl. 46, N. 1, pp. 10~15, 2009. Refractive Index Dispersin f Sputter-Depsited Silicn-Rich Silica Thin Films Byeng Kyu Jin and Yng Gyu Chi Department f Materials Science and Engineering, Krea Aerspace University, Gyenggi 412-791, Krea (Received July 7, 2008; Revised Nvember 26, 2008; Accepted December 3, 2008) rl g e ³Á ³ w wœ w wœ œw (2008 7 7 ; 2008 11 26 ; 2008 12 3 ) ABSTRACT We have fabricated silicn-rich silica thin films via RF magnetrn sputtering using a SiO target. Thickness evlutin and micrstructure change f such SiO x (1< x<2) films were investigated in terms f the substrate temperature during the depsitin. Optical interference patterns btained frm a spectrscpic reflectmeter were analyzed t yield refractive index dispersin prfiles f the depsited film layers in the visible wavelengths. Changes f the refractive indexes were then explained in cnnectin with changes in micrstructure and cmpsitin f the silicn-rich silicn xide films. Increase in the number f the Si-Si bnds frmed inside the SiO x thin films turned ut t be mainly respnsible fr the increase f refractive index. Key wrds : Silicn-rich silica, Thin film, Refractive index, Sputtering 1. Ÿw w sƒ w š w wù. q p» q w w, Ÿ j» w. w w ƒ l» Ÿ p j w e.,» z w»» ƒ w w y Ÿ p y w. 1,2) wr, j Ÿw w w. s q e q w w w ƒ q xk j» w w. 3,4) Ÿw w w j» z w l œ y w w. Crrespnding authr : Yng Gyu Chi E-mail : ygchi@kau.ac.kr Tel : +82-2-300-0169 Fax : +82-2-3158-3770 g»q x e t silicn-ninsulatr xk z y g» q,»» sww silicn phtnics w y š. g e ƒ 5,6) f w q š, œ x ƒ š» e» q j» e w ƒ Ÿ w. 3,4) j» e j w y. g» j ƒw ù e j w ù, ƒƒ ³ w ƒ wš œ y w w v w. k g yw y k silicn-rich silicn xide (SRSO) wš œ q wš w. SRSO w yw», 7-10), g 11) 12,13) rl 14,15) w š. rl k w vw, g 16,17) 10

e wš» CMOS œ w ƒ. rl w SRSO w g k» j w ù g e k w. ù w œ ƒ ƒw š x y ƒ v w. w rl œ w SiO k y w SRSO w,»q y w Ì y w q wš w. SRSO w» šƒ ù, 18-21) w p rl SiO x (1 x 2) w š w k. 2. x»q (100) w ƒ g(siltrnix C.) y w px nx g»q w ywš w.»q 20 20 mm 2 w z m ƒƒ 40 q wš ƒ w»q t w w. v w k 99.9% SiO(Super Cnductr Materials C.) w. ü œ» œ 2.6 10 6 Trr w š ƒ 15 sccm w œ œ 1.7 10 2 Trrƒ w. v x š q» 150 W w w š œ 2 w»q 8z z k Ì ³ š w. k œ w w»q 50 C l 400 C¾ 50 C y j»q SiO x v w. ƒ v» 900 C 60 w z þw. g y 700 C w, w œ 22) e v Si SiO 2 swwù k q. Ì y w x x (JEOL, JSM-6700) y w, Ÿ x d»(spectrscpic reflectmeter; K-MAC C., ST2000DLXn) w 400~900 nm t w w w rp d w. w Si-Si w y w» w t y Ÿ»(FTIR; Perkin Elmer, Spectra 100) w rl g e 11 Fig. 1. Thicknesses f SiO x films pltted as a functin f substrate temperature. 450~1500 cm 1 d w. 3. š 3.1. Ì y»q Ìƒ yw, y w» w x x mw ƒ v Ì d w. d z s³e w Fig. 1 ùkü. SiO x Ì»q ƒ 50 C 250 C¾ ~215 nm ~124 nm w š z 400 C¾ ~253 nm ƒw.»q ƒ ü»wš v ü š y ƒ j. w š y 23) ƒ k w š ƒ w ƒw. ù»q ƒ ƒw»q w., k»q ƒ»q ƒ w w. x»q 24) 250 C¾ Ìƒ w Ìƒ ƒw ƒ. 3.2. j» y»q ƒ e w y w» w x x w d w. t SiO x 46«1y(2009)

진병규 최용규 12 Fig. 3. Particle sizes f SiOx films pltted as a functin f substrate temperature. 의 변화는 증착되는 입자의 이동 및 재증발(re-evapratin) 등을 야기하게 되고 이는 증착되는 박막의 두께 및 미세 구조에 영향을 주고 있음을 확인할 수 있다. 박막 내 입자는 박막에 조사되는 빛의 산란을 유발하고 따라서 입자크기의 변화와 같은 미세구조의 변화는 주요 광학적 특성 중 하나인 산란 강도의 변화를 야기한다. 특 히 입자의 크기가 조사되는 빛의 파장에 비해 약 1/10 정 도일 경우 레일라이 산란이 주로 발생하게 된다. 본 연구 에서 굴절률의 측정에 사용된 분광형 반사측정기의 파장 대역은 가시광(400~900 nm) 영역이었으며, 이러한 파장 은 제작된 SiO 박막의 입자크기보다 10배 이상 크기 때 문에 입자에 의한 레일라이 산란이 발생할 것임을 확인 x Fig. 2. FE-SEM micrgraphs f the SiOx films fr substrate temperatures f (a) 50C, (b) 250C, and (c) 400C. 박막 샘플의 사진을 Fig. 2에 도시하였다. 이러한 전계 방 출형 주사전자현미경 사진을 이미지 분석 방법을 통해 각 SiO 박막을 구성하는 입자의 평균크기를 구하였으며, 그 결과를 기판온도의 함수로써 Fig. 3에 나타내었다. 박막 내 입자의 크기가 박막의 두께가 감소하면서 커지는 것 을 알 수 있으며, 이는 기판의 온도가 증가하면서 박막 내 입자의 이동도가 증가하게 되고 그에 따라 입자의 밀 집성이 증가하여 입자의 크기가 조대화되는 것으로써 설 명될 수 있다. 반면 특정 온도 이상에서는 입자의 이동보 다 상대적으로 증착되는 양이 많아 입자의 이동이 쉽게 이루어지지 못해 입자의 조대화가 어렵다. 본 연구에 서 제작된 SiO 박막의 경우 250 C를 경계로 입자크기의 변화 경향이 바뀌는 것을 볼 수 있으며, 이러한 경향성은 박막의 두께 변화와 정확히 일치하고 있다. 즉, 기판온도 x 25,26) x 한국세라믹학회지 Fig. 4. Relative Rayleigh scattering intensities f the SiOx films pltted as a functin f substrate temperature.

w. j» y y y w d e w q w» w y w. 27) rl g e 13 9π 2 V 2 I s I 0 ------------- 2d 2 λ 4 ( m 2 1) m 2 2 = [ ( + 2) ]2 ( 1 + cs θ )» V d ƒƒ v w v Ì ùkü, λ v q. θ m ƒƒ ƒ. ƒ v w Fig. 4 w. j»ƒ ƒ j»q 250 C v ƒ ƒ j y w, Fig. 3 Fig. 4 mw ƒ ü j» y w w ƒ. 3.3. Ÿx d»»q w ƒ w ùkù ql xk Ì w y w., w txw. 2π R A+ Bcs ----- ( n ik)d λ» R A B, n k ƒƒ Ÿ w. 28) Ÿx d» d ƒ v ql x d w v Ì w ƒ Ÿ ƒ SiO x w, Fig. 5 w. w w 400 nm 700 nm Fig. 6 ùkü. q f x p ùküš ù w ƒ.» (2)» w ƒ Ÿ ƒ 10 w j ùkû» 18 g ƒ w w g w. B n n( λ) = A n + ---- +----- λ 2 C n λ 4» A n, B n C n g w, SiO x g A n SiO 2 g A n (1.458) SiO g A n (1.860) ƒ (1) (2) (3) Fig. 5. Refractive index dispersin spectra f the SiO x film fr substrate temperature f (a) 50, 100, 250, 300, and 400 C, (b) 200 C, (c) 350 C, and (d) 200 C. Fig. 6. Refractive indices f the SiO x film at (a) 400 nm and (b) 700 nm pltted as a functin f substrate temperature. Squares and circles represent refractive indices at 400 nm and 700 nm, respectively. y. ƒ w j» y w y w w, y». d ƒ w w e q w. w» q w w»,»q w j» Ì y w. j w dw 46«1y(2009)

14 ³Á ³ Fig. 7. Representative FT-IR transmittance spectrum f a SiO x film. Nte that this film was fabricated under the substrate temperature f 50 C., y w» w t y Ÿ» y w ƒ n rp d w.»q n rp d wš, z n rp d w g»q w w. t v n rp Fig. 7 w.»q z Ì z w z n rp ƒ w vj w w, w w y w. Fig. 7 w rp ~ 610 cm 1 ùkù Si-Si w w, 29) ƒ v w vj w Fig. 8 w. Si-Si w ƒ f w, w w ƒ SiO x g w ƒw w» g ä SRSO w y w. wr, w e w ƒ v w œ e Fig. 2 y w»œ ùkü» y y j ù, ƒ v w. w SiO x SiO 2 SiO š rp 30) Si-Si w y», 1< x <2 w. t v w EDS mw y. Fig. 8. Refractive indices at 400 nm f the SiO x films pltted as a functin f relative amunt f the Si-Si bnds present in each SiO x film. 4. SiO k w p rl SiO x (1< x <2) w,»q y Ì j»ƒ y ƒ y w. Ÿ x d» d w SiO x»q w, w Si- Si w w q. w g w w x y w. Acknwledgments 2006 w w w (KRF-2006-331- D00238). REFERENCES 1. S. V. Bhat, A. Gvindaraj, and C. N. R. Ra, Tuning the Emissin Bands f Nanphsphrs Thrugh the Refractive Index f the Medium, Chem. Phys. Lett., 422 [4-6] 323-27 (2006). 2. A. L. Lpez, M. A. Mijares, and O. Malik, Optical and Electrical Prperties f Silicn Rich Oxide Films fr Optical Sensrs, Sensr Actuatr. A, 132 [1] 278-82 (2006). 3. D. M. Ye, and S. Y. Shin, Plymer-silica Hybrid 1 2 Thermptic Switch with Lw Crsstalk, Optic. Cmm., 267 [2] 388-93 (2006). 4. M. C. Oh, C. Zhang, H. J. Lee, W. H. Steier, and H. R. Fet- w wz

rl g e 15 terman, Lw-Lss Intercnnectin Between Electrptic and Passive Plymer Waveguide With a Vertical Taper, IEEE Phtn. Technl. Lett., 14 [8] 1121-23 (2002). 5. W. Jiang, L. Gu, X. Chen, and R. T. Chen, Phtnic Crystal Waveguide Mduluatrs fr Silicn Phtnics: Device Physics and Sme Recent Prgress, Slid State Electrn., 51 [10] 1278-86 (2007). 6. H. Wng, V. Filip, C. K. Wng, and P. S. Chung, Silicn Integrated Phtnics Begins t Revlutinize, Micrelectrn. Reliab., 47 [1] 1-10 (2007). 7. M. Riera, J. A. Rdriguez, J. Barret, and C. Dminguez, Mdeling f Nn-stichimetric Silicn Oxides Obtained by Plasma Enhanced Chemical Vapur Depsitin Prcess, Thin Slid Films, 515 [7-8] 3380-86 (2007). 8. C. S. Yang, C. J. Lin, P. Y. Kuei, S. F. Hrng, C. C. H. Hsu, and M. C. Liaw, Quantum Size Effects n Phtluminescence frm Si Nancrystals in PECVD Silicn-richxide, Appl. Sur. Sci., 113-114 116-20 (1997). 9. G. Shi, G. Xu, and G. Han, Preparatin and Phtluminescence f Nancrystalline Si-rich Silicn Oxide Films by PECVD, Mater. Lett., 61 [2] 463-65 (2006). 10. M. Burchielli, G. Cnte, G. Fameli, C. Felici, M. C. Rssi, A. Rubin, S. Salvatri, and F. Villani, Functinal Prperties f Silicn Nancrystals in Oxygen-rich Amrphus Matrices Frmed by Laser Irradiatin f Substichimetric Silicn Oxides, Mater. Sci. Eng. C, 19 [1-2] 175-79 (2002). 11. J. H. Sn, H. B. Kim, C. N. Whang, M. C. Sung, K. Jeng, S. Im, and K. H. Chae, Visible Phtluminescence frm Si In-beam-mixed SiO 2 /Si/SiO 2 Layers Depsited by E-beam Evapratin, Nucl. Instrum. Meth. Phys. Res. B, 216 346-49 (2004). 12. T. S. Iwayama, Y. Tera, A. Kamiya, M. Takeda, S. Naka, and K. Saith, Visible Phtluminescence frm Silicn Nancrystals Frmed in Silicn Dixide by In Implantatin and Thermal Prcessing, Thin Slid Films, 276 [1-2] 104-07 (1996). 13. L. S. Lia, X. M. Ba, N. S. Li, X. Q. Zheng, and N. B. Min, Blue-, Green-, and Red-light Emissin frm Si + - Implanted Thermal SiO 2 Films n Crystalline Silicn, J. Lumin., 68 [2] 199-204 (1996). 14. L. Bi, Y. He and J. Y. Feng, Effect f Pst-annealing in Oxygen Atmsphere n the Phtluminescence Prperties f Nc-si Rich SiO 2 Films, J. Cryst. Grwth., 289 [2] 564-67 (2006). 15. S. Charvet, R. Madeln, R. Rizk, B. Garrid, O. G. Varna, M. Lpez, A. P. Rdriguez, and J. R. Mrante, Substrate Temperature Dependence f the Phtluminescence Efficiency f C-sputtered Si/SiO 2 Layers, J. Lumin., 80 [1] 241-45 (1999). 16. A. Sassella, A. Brghesi, F. Crni, A. Mnelli, G. Ottaviani, R. Tnini, B. Pivac, M. Bacchetta, and L. Zantti, Infrared Study f Si-rich Silicn Oxide Films Depsited by Plasmaenhanced Chemical Vapr Depsitin, J. Vac. Sci. Technl. A, 15 [2] 377-89 (1997). 17. R. H. Dremus, Diffusin f Oxygen and Silicn in Silicn: Silicn Mnxide Mdel, Mater. Res. Sc., 16 [1] 185-91 (2001). 18. F. Bertin, T. Barn, D. Marille, F. Martin, A. Chabli, and M. Dupuy, Charaterizatin f Depsited Nancrystalline Silicn by Spectrscpic Ellipsmetry, Phys. Stat. Sl., 175 [405] 405-12 (1999). 19. C. Gravalidis, S. Lgthetidis, N. Hatziaras, A. Laskarakis, I. Tsiaussis, and N. Frangis, Characterizatin f Si Nancrystals int SiO 2 Matrix, Appl. Surf. Sci., 253 [1] 385-88 (2006). 20. S. Charvet, R. Madeln, F. Gurbilleau, and R. Rizk, Ellipsmetric Spectrscpy Study f Phtluminescent Si/SiO 2 Systems Obtained by Magnetrn C-sputtering, J. Lumin., 80 [1-4] 257-61 (1999). 21. B. Sun, Y. R. Chen, P. Zhu, C. H. Xu, Y. F. Kng, Y. X. Zheng, and L. Y. Chen, Ellipsmetric Study f the Optical Prperties f Silicn-Based Si:SiO 2 Cmpsite Thin Films under Different Annealing Temperatures, J. Krean Phys. Sc., 49 [5] 2184-87 (2006). 22. P. Rura, J. Farjas, A. Pinyl, and E. Bertran, The Crystallizatin Temperature f Silicn Nanparticles, Nantechnl., 18 [17] 175705.1-4 (2007). 23. J. Xu, H. Umehara, and I. Kjima, Effect f Depsitin Parameters n Cmpsitin, Structures, Density and Tpgraphy f CrN Films Depsited by r.f. Magnetrn Sputtering, Appl. Surf. Sci., 201 [1-4] 208-18 (2002). 24. R. Schmidt, A. Basu, A. W. Brinkman, T. P. A. Hase, Z. Klusek, S. Pierzgalski, and P. K. Datta, Structural Prperties f rf Magnetrn Sputter Depsited Nickel Manganate Thin Films, Surf. Sci., 595 [1-3] 239-48 (2005). 25. H. Jimenez, E. Restrep, and A. Devia, Effect f the Substrate Temperature in ZrN Catings Grwn by the Pulsed Arc Technique Studied by XRD, Surf. Cating. Tech., 201 [3-4] 1594-601 (2006). 26. S. T. Lin and C. Lee, Grwth f Tantalum Brn Nitride Films n Si by Rati Frequency Reactive Sputtering: Effect f N 2 /Ar Flw Rati, Mater. Chem. Phys., 82 [3] 691-97 (2003). 27. R. Tilley, Clur and the Optical Prperties f Materials, pp. 110-17, Jhn Willey & Sns, New Yrk, 2000. 28. S. G. Jung, Display Prcess and Thin Film Thickness Measurement, Prspective f Industrial Chemistry, 8 [4] 96-105 (2005). 29. M. Saadun, B. Bessaïs, N. Mliki, M. Ferid, H. Ezzauia, and R. Bennaceur, Frmatin f Luminescent (NH 4 ) 2 SiF 6 Phase frm Vapur Etching-based Prus Silicn, Appl. Surf. Sci., 210 [3] 240-48 (2003). 30. M. Barzzi, E. Iacb, L. Vanzetti, M. Bersani, M. Anderle, G. Pucker, and C. Kmpchlis, Analytical Methdlgy Develpment fr Silicn-rich-xide Chemical and Physical Characterizatin, Rev. Adv. Mater. Sci., 15 [1] 56-62 (2007). 46«1y(2009)