Surface Morphology
Of PbZr o.szsTio,'1s0 J (PZ1) Films (Irzaman)
Irzamaw,4, Azizahwatiz.4 ,A. Fuad3,4,P. Arifin4, M. Budiman4 and M. Barmawi4 lLaboratory of Materia! Phy~ics, Department of Physics, FMIPA IPB, JI. Raya Pajajaran Bogar, Indonesia -16144 2Department of Physics, FMIPA Universitas Riau, Indonesia 3Department of Physics, FMIPA Universitas Negeri Malang, Indonesia -65145 4Department of Physics, FMIPA ITB, JI. Ganeca 10 Bandung, Indonesia -40132
ABSTRACT SURFACE MORPHOLOGY OF PbZrO.~1~Tio.47~03(PZT) FILMS. Thin films lead zirconium titanate (pbZros1sTiO47S0J= PZT) deposited on Pt (200)/Si (100) using the dc-unbalanced magnetron sputtering (DC-UBMS) method have been investigated. The films were grown at deposition temperatures of 700 .C, 750 .C, 800.C for 3 hours, followed by an annealed at 700.C for 1 hour. X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM) observation were employed to characterize the grown films. The films show tetragonal structure with preferred orientation in (100), (111), (200) planes. The calculated lattice constants are a = b = 4.141 A, c = 3.828 A. In the range of deposition temperatures between 700 and 800 .C, a better crystalline quality was achieved for the film grown at 750.C due to the increase of the grain size. However, increasesthe growth temperature resulted desorption of the grown films from the surface lead to non-homogen feature of surface morphology. Key word\" : surface morphology, PZT, thin film, DC-UBMS method, XRD, SEM.
ABSTRAK MORFOLOGI PERMUKAAN OARI FILM TIPIS PbZr O.~2~ Tio.47~O3 (PZT). Telah dikaji penumbuhan film tipis lead zirkonium titanat (PbZrOS2S TiO47S0)= PZT) Pt (200)/Si (100) dengan metode unbalanced magnetron sputtering (DC-UBMS). Karakterisasi film tipis dilakukan denganteknik XRD dan SEM. Suhu penumbuhan untuk menumbuhkan film tipis PZT adalah 700.C, 750.C, 800.C masing-masing selama3 jam dan kemudian dilakukan annealing pada700.C selama 1 jam. Kristal tilm tipis diamati dengan XRD berbentuk bidang-bidang kristal (100), (111), (200) dengan struktur tetragonal dan tetapan kisi sebesar a = b = 4,141 A, c = 3,828 A. Dalam selang suhu penumbuhan antara 700.C dan 800.C, maka pada suhu 750.C diperoleh kualitas film yang terbaik dengan meningkatnya ukuan butir. Semakin tinggi suhu penumbuhan menyebabkan terjadinya penguapanpada film yang telah terbentuk dan dari analisis morfologi permukaan menunjukkan bahwa morfologi permukaan film tipis belum
homogen. Kata kunci : Mortologi permukaan,PlI, film tipis, metodeDC-UBMS, XRD, SEM.
INTRODUCTION A pyroelectric infrared (IR) detector has advantages of wavelight independent sensitivity and can be operated at room temperature. It is also expected to provide various thermal observations for objects at near ambient temperature. Thin films of PbTiO3 and PbZr"Ti,."O3 have been used as pyroelectric IR detectors. I PbZr" Ti\."O3 films can be grown by various methods, such as sputtering [2,3,4,5,6,7,8], chemical solution deposition (CSD) [9,10,11,12,13], pulsed laser deposition (PLD), [14,15] and metal organic chemical vapor deposition (MOCVD)[16]. The varian of sputtering method, which is, the DC Unbalanced Magnetron Sputtering (DC UBMS) method is of particular interest because of its good control of stoichiometry, ease of fabrication and low or high temperature synthesis. It was reported that thin film grown by DC-UBMS has stoichiometry similar to the bulk target.
PbZros2s TiO4750)(PZT) has been of immense interest in the use of ferroelectric thin film in pyroelectric sensorapplications. In this paper we report on the fabrication of PbZros25 TiO47S0)(PZT) thin films by DC UBMS. The crystal structure and the surface morphology of the grown films related to the growth temperatures are described.
EXPERIMENTAL PROCEDURE A lead zirconium titanate (PZT) thin film was deposited on Pt (200)/Si (100) substrates by DC
Unbalanced Magnetron Sputtering methods. A5.302 gram Leadtitanate(PbTiO3,99%) and 6.698gram Lead zirconate (PbzrO" 99,7 %) were initially mixed in a bowl for 6 hours. The mixture was then pressed at 31.43 MPa for 15 minutes to forma pellet followed by a sintering at 850°C for 10hours. The PZT thin film was grown on 12romx 12 rom
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Prosiding Pertemuan llmiah llmu Pengetahuan dan Teknologi Bahan 2002 Serpong, 22 -23 Oktober 2002
Pt(200)/Si (100) substrateusing deposition parameters shown in Table 1. The film structure was analyzed by x-ray diffraction (XRD). The XRD spectrawererecorded on a Diano type 2100E diffractometer using CuKa. radiation at 30 KVand 30 mA (900 watt). The surface morphology and thickness of the films were examined by SEM JEOL type JSM-35C. The treatments of growth PZT thin films using DC-UBMS method are given in Table 2. Summary of sample fabrication and
ISSN1411-2213
characterization is given in Figure I. The various sets of planes in a lattice have various values of interplanar spacing. The planes of large spacing have low indices and pass through a high a density of lattice points, whereas the reverse is true for planesof small spacing.The interplanar spacing (d/ir) is a function of both plane indices (hk/) and lattice constants (a, b, c, cx.,13,y). The relation between interplanar spacing and lattice constant for tetragonal structureis given inEq. (1)[ 17,1]: h2 +k2
[2 _2
(1
andtheBraggLawis givenin Eq. (2) : ). = 2d sin ()
(2)
where: d = the interplanar spacing;a, b, c = lattice constants;h, k, I = the Miller indices; Iv = wave length (for Cutarget= 1.54056A); e = the diffractionangle.
RESULTSAND DISCUSSION
Table 2. Treatment of growth PZT thin films using DC-UBMS method
I
i
m I
m
I
I
that the intensity of the (100) reflection increasesas the deposition temperatureincreases.The Full Width at Half Maximum (FWHM) of (100) plane decreases as the deposition temperature increases from 700°C to 750°C, but the FWHM of (100) plane increases as the deposition temperature increases from 750°C to 800°C as shown in Figure 3. This indicated that the grown film has good crystallinity for high deposition temperature, however,the high temperature may cause desorption of the deposited layer lead to the re-orientation of the plane
II
.""'.
""' a"" L..d ,;,...,.
L..dli"...,c
(PbT;O,,99%1
Figure 2 shows XRD spectra ofPZT. The films are polycrystall in tetragonal structure with preferred orientation in (100), (Ill), (200) planes. The calculated lattice constant are a = b = 4.141 A, and c = 3.828 A. (in literature a=b= 4.036 A, c = 4.146 A)[19]. It is shown
[PbZ,O,. ".7%J
phases.
Figure 4 showsurfacemorphologyofPZT thin films grownat 700°C, 750°C and800°C. Roundwith
M ,Kin. by bowl oipol;,bin. Co,, '0."
12.,
,fPbZ,
Ti..,.O, (PZT)powd.,
A p,II,. p,...m. by Ib, p"""" '1.4' MPO..., l' m mo'" .nd ,in'.,m, by fom'" ,. .'O'C Co,10boo,.
11 ,ram. .fPZT
bulk
Proparati.. .roc V,bala.cod ~a..o'r.. Sputt.ri.,(VBMS) DC"BMS m..hod.. d.po.";O" p".m.,., d.po.";O"..mp".,u,. 'OO'C ., bou,.). Im. 'OO'C(I hou,). ..,uum p,...u,. (Illor,). pl..m. po.., .~::.OW.,..;~.A"O,.,O~"m..O ."m~l)
PZTth;"f;lm.o" 11...,xllmmofPI/,100j/Si(IOOI..b.,r". A..I,,;.. ..d ,h""I";';..lh, 'I.."." (XRDD;,.. Iyp' 11001), Ih, ,.ri", m"Ph.I..y ..d Ihi,k.,.. .flh, film, (SEMlEOLlyp,'SM.)JC).
,~::::~ Figure 1. Summary characterization
206
of
sample
fabrication
and
Figure 2. The diffraction pattern taken by XRD of PZT thin films on Pt(200)/Si (100) substrate at deposition temperature 700.C, 7S0.C, 800.C for 3 hours, annealingtemperature700.C tor 1 hour.
Surface Morphology
Of PhZr O.SlsTiO.17S03 (PZ1) Fibns (lrzaman)
0.35
c, 4J
~
03
~ :r
~ 0.25
"'
02 r. 650
"~. 700 Deposition
750 temperature
.i 800
850
(oC)
Figure 3. The Full Width at Half Maximum (FWHM) of (100) plane of PZT thin films on Pt(200)/Si (100) substrateat depositiontemperature700.C, 750.C, 800.C tor 3 hours, annealingtemperature700°C tor I hour.
Figure S. The cross section of PZT thin films on Pt(200)/Si (100) substrate at annealing temperature 700.C for 1 hours (at 20000x magnification) by SEM, depositiontemperature(a) 700.C, (b) 750.C, (c) 800.C for 3 hours.
relatively homogen features are formed at deposition temperature of 700 .C. Increases the deposition temperature lead to elongation the feature and become irregular columns at deposition temperature of800 .C. However,the increaseof deposition temperatureresulted inhomogeneous surface morphology, probably due to desorption from the substrate surface at high
Figure 4. The surface morphology of PZT thin films on Pt(200)/Si (100) substrateat annealingtemperature 700.C tor I hours (at 100OOxmagnitication) by SEM, depositiontemperature(a) 700.C, (b) 750.C, (c) 800.C tor 3 hours.
temperature. The film thickness was measured by means of cross section Scanning Electron Microscopy (SEM) measurement. Figure 5 show the cross section SEM images of the film grown at 700 .C , 750"C and 800 .C. Although the deposition time was the same for all deposition temperatures, the growth rate depends on deposition temperature. Figure 6 shows the growth rate as a function of deposition temperature. At deposition
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Pr(}.~iding Pertemuan llmiah llmu Pengetahuan dan Teknologi Bahan 2002 Serp(}ng. 22 -23 Oktober 2002
temperature of 700 °C , 750 °C and 800 "C, the film thicknessare 500 nm, 1100nm and 600 nm, respectively. At deposition temperature of750 or, the groMh rate is the highest and increasing the temperature lead to a reduce of the groMh rate. This presumably becauseof desoprtion of the grown film due to high temperature processesas confirmed by SEM images.
ISSN 1411-2213
Nigth Vision Cameras, Compound Semiconductor Spring 11,4 (4), (1998), 17-23. [2J. N.J. WU, Y.S. CHEN, S. DORDERIC, and A. IGNATIEV, Pyroelectric IR Sensor Based on Oxide Heterostroctures on Si (100) and LaAIOJ (100) Substrates.Proceeding ThirdIntemationai Conference on Thin Film Physiscs and Applications. SPIE 3175,(1997),256-261. [3]I. K. SUU, Preparation of (Pb,La)(Zr, Ti)OJ Ferroelectric Films by RF Sputtering on Large Substrate. Jpn. J. Appl. Phy.S'.,35 (9B), (1996), 4967-4971. A. FUAD dan M. BARMAWI. [4].IRZAMAN, Penumbuhan Film Tipis PbTiOJ dengan Metode DC Unbalanced Magnetron Sputtering (DC UBMS). Prosiding Pertemuan Ilmiah IImu Pengetahuan dan Teknologi Bahan '99, Serpong, (1999),196-199. UMIATI, N.A.K., IRZAMAN, M. BUDIMAN, M. BARMAWI. Efek Annealing pada Penumbuhan Film Tipis Ferroelektrik PbZrO62S TiO37S0J' Jurnal Kontribusi Fisika Indonesia. ITB Bandung, 12 (4), (2001),94-98. [6]J. IRZAMAN, A FUAD, P. ARIFIN, M BUDllvIAN, M. BARMAWI. Pyroelectric Properties of Tantalum Oxide Doped Lead Zirconium Titanate (PTZT) Thin Films Grown by DC Unbalanced Magnetron Sputtering and Its Application for IR sensor. Prosiding Simposium Fisika Nasional, Jurusan Fisika FMIPA ITS Surabaya, 2, (2002), 80-84. -:. l7J IRZAMAN, Y. DARVINA, A. FUAD, P. ARIFlN, M. BUDIMAN, M. BARMAWI. Voltage Responsivity of Tantalum Oxide Doped Lead Zirconium Titanate (PTZT) Thin Films and Its Application for IR Sensor. Accepted for Publication to Pro.\'iding Simposium Fi.S'ika Na..\'ional,Himpunan Fisika Indonesia (HFI) Pusat, Universitas Udayana Bali, (2002). ---IRZAMAN, Y. DARVINA, A. FUAD, H. [8] SUTANTO, P. ARIFIN, M. BUDIMAN, M. BARMA WI. C- V Properties of Lead Zirconium Titanate (PbZros2s TiO47S0J) Thin Films. Accepted for Publication to Prosiding Seminar Keramik Nasional, Balai Besar Industri Keramik Bandung, Departemen Perindustrian dan Perdagangan, [5]I.
CONCLUSION We have investigated the dependence of temperature deposition on the surface morphology and crystall structure ofPZT thin films. The films were grown at temperatures of 700°C, 750 °C, 800 °C for 3 hours followed by an annealed at 700°C for 1 hour. The films are po1ycrystall in tetragonal structure with preferred orientation in (100), (111), (200) planes, and the calculated lattice constants are a = b = 4.141 A, c = 3.828 A. The surfacemorphology and the crystalline quality of the grown films significantly depend on the deposition temperature. At deposition temperature of 700 °C relatively homogen surface are formed. Increasing the deposition temperature lead to inhomogeneous surface morphology presumably due desorption of the grown layer at high temperature. However at deposition temperature of 750 °C, a better crystalline quality are achieved.
ACKNOWLEDGEMENT This work was supportedby Center Grant URGE Project, The Ministry of National Education, The Republic of Indonesia, under contract No. 0O8/CG//III/URGE/1997 This work was supported by Center Grant URGE Project,The Ministry of National Education, The Republic of Indonesia, under contract No. tX)8/CG//IlI/URGE/1997
REFERENCES [1]. T. WHITAKER, Focal Plane Arrays Fabricated from Compound Semiconductor Materials are at The Heart of Many Infrared Imaging Systemsand 208
(2002). PINTILIE, M. ALEXE, I. PINTILIE and T. BOTILA, Photovoltaic Effect in PbS/PbTiO)/Si Heterostructures..4ppl. Phy.\'.Left.. 69 (11), (1996), 1571-1573. [10J. Y. HIDEKAZE, Influence of Buffer Layer Insertion and Annealing Mode Upon Microstructures and Ferroelectric Characteristics of Sol-GelDerived Pb(Zr,Ti)O3 Thin Films. .lpn. J. .4ppl. Phys.,35 (9B), (1996), 4941-4945.
---L. L9]
Surface Morphology
Of PbZr O,SlSTiO,47S0j (PZ7) Films (Irzaman)
[II). J.Y. Zhang, and I. W. Boyd, CharacterizationofPZT Films Formed by Photo-Decomposition of Metal Organic Polymer. Jpn. J. ,4pp/. Phy.\'., 38 (4A), L393 -L394,(1999). [12). Y. FUJIl\,10RI,T.NAKAMURAandH.TAKASU, Low- Temperature Crystallization of Sol-Gel Derived PZT Thin Films. Jpn. J. App/. Ph.vs., 38 (9B),(1999), 5346-5349. [13]. C.R. CHO, W.J. LEE, B.G. YU and B. W. KIM, Dielectric and Ferroelectric Response as A Function of Annealing Temperature and FilmThickness of Sol-Gel Deposited PbZros2TiO4SO) Thin Film. J. App/. Ph.vs., 86 (5), (1999),2700-2711. [14). D.J. DI MARIA, Growth and Measurement of Ferroelectric Lead Zirconuim Titanate (PbZrx Ti._XO)) on Diamond by Pulse L~ser Deposition (PLD). J. App/. Phys., 86 (3), (1999), 1630-1633. [15]. H.WU.,J.YU,X.DONG, W. ZHOUandY WANG, Characteristics ofPZT Thin Films on p-Si with a Buffer Layer of Bi4Ti)OI2 Prepared by Pulsed Laser Deposition. Jpn. J. App/. Phys., 40 (3A), (2001), 1388-1390. [16]. J.H. KIM, and F.F. LANGE, Epitaxial Growth of PbZrosTiOSO)Thin Films on (00 1) LaAlO) by The Chemical Solution Deposition Method J. Mate/: Res., 14(10),(1999),4004-4010. [17). B.D. CULLITY, E/ement.~ of X-ray Di./fraction, Second Edition, Addison Wesley Publishing
Jawaban
1. Menghilangkan pertumbuhan PZT (111) dalambulk dilakukan doping (didadah) dengan senyawaoksida (seperti Ta205, In203) karena dapat mencegah pertumbuhanbidang (iii) tersebut.Sedangkandalam film tipisPZT diatassubstratPt (200)/Si (100)bidang (Ill) sudah menghilang, ini disebabkan bidang kristal film berkecendrungan mengikuti bidang substrat (epitaxy).
DR Ridwan,P31B-BATAN Per1anyaan
1. Bagaimana perubahan sifat elektrik dengan perubahankristal sistembahan? 2. Analisamikrostrukturterkaitdenganperubahansifat dielektrikbahanakanmenjadimenarik'1 Jawaban 1. Pembahan sifat e1ektrik dengan pembahan kristal sistembahan berkorelasi 1inier,daD dapat diketahui dengan bantuan software fourier transfor yang menghasilkan pembahan dielektrik bahan diiringi pembahan orientasi bidang daD FWHM. 2. Sangat menarik karena dengan bantuan fourier transpor terkuak hubungan nilai die1ektrik, suhu Debye daD sifat pyroe/ektrik dengan pembahan rnikrostruktur bahan.
Company Inc., London, (1978),46. [18). C. SURYANARAYANA and M.G. NORTON, X-ray Diffraction: A Practical ,4pproach, Plenum Press,London, (1998),46. [19]. KAKEGAWA, (1977) : in JCPDS-International Centerfor Diffraction Data (JCPDS-ICDD),(1995).
TANYAJAWAB MadeSumartiKardha,P3TIR-BATAN
Pertanyaan 1. Mengapaada pick pada serbuk lebih menonjol dibandingkanpadafilm tipis.
Jawaban 1. Oalam serbuk (bulk) PZT orientasi kristalnya polikristal, maka bidang (Ill) muncuI, namun dalam film tipis PZT yang ditumbuhkan diatas substrat Pt(200}/Si(100} menghilang karena orientasibidang PZT pada film tipis mengikuti orientasi substratnya kearah sumbu x (epitaxy)
Toifur,Univ. AhmadDahlan-Yogyakarta Pel1anyaan
1. UntukmenghilangkanpertumbuhanPZT (Ill) kirakira apayangakandilakukan
Ke Daftar Isi 209
