• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 II
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• pp.727-730
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• 2003

Thin tin oxide film with nano-size particle was prepared on silicon substrate by hydrothermal synthetic method and successive sol-gel spin coating method. The fabrication method of tin oxide film with ultrafine nano-size crystalline structure was tried to be applied to fabrication of micro gas sensor array on silicon substrate. The tin oxide film on silicon substrate was well patterned by chemical etching upto 5${\mu}{\textrm}{m}$width and showed very uniform flatness. The tin oxide film preparation method and patterning method were successfully applied to newly proposed 2-dimensional micro sensor fabrication.

• 한국결정성장학회지
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• 제18권1호
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• pp.50-55
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• 2008

졸-겔 공정을 이용하여 유리기판 위에 Al-doped ZnO(AZO) 박막을 제조하였고, AZO 박막의 특성에 대하여 Al 전구체 종류 및 post-annealing 온도가 미치는 영향에 대하여 고찰하였다. AZO 박막 제조용 졸은 zinc acetate, EtOH, MEA 등을 사용하여 제조하였고, Al doping 을 위한 전구체로는 aluminum nitrate 와 aluminum chloride 를 사용하였다. Sol 내의 Zn 농도는 0.5 mol/l 로 하였고, Al doping 양은 Zn 대비 1 at%로 고정하였다. 유리기판 위에 졸을 spin-coating 한 후 $550^{\circ}C$에서 2 시간 동안 열처리한 후, $N_2$와 $H_2$의 비가 9 : 1인 환원 분위기 내에서 $300^{\circ}C,\;400^{\circ}C,\;500^{\circ}C$인 온도에서 2시간 동안 post-annealing을 진행하였다. 제조된 AZO 박막의 구조적, 전기적, 광학적 특성은 XRD, FE-SEM, AFM, Hall effect measurement system 및 UV-Visible spectroscopy를 이용하여 분석하였다. Al 전구체로서 aluminum nitrate 를 사용한 경우가 aluminum chloride 를 사용하여 제조한 AZO 박막보다 우수한 광학적, 전기적 특성을 나타내었으며, post-annealing 온도가 증가함에 따라 비저항과 투과율은 감소하였다. $500^{\circ}C$에서 post-annealing한 AZO 박막의 전기비저항 값은 $2{\times}10^{-3}{\Omega}{\cdot}cm$이었고, 투과율은 $300^{\circ}C$에서 91%로 가장 높게 나타났다.

• 한국세라믹학회지
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• 제31권5호
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• pp.499-504
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• 1994

PbTiO3 thin films were prepared by sol-gel spin coating method using metal alkoxide and diethanolamine (DEA). The precipitation of the PbTiO3 sol occurred at pH 7.3 with HNO3 addition, regardless of the amount of DEA. The gelation time of the PbTiO3 sol was reduced with increasing amount of HNO3 and/or water. When the PbTiO3 films prepared by 0.2 molar coating solution were annealed at $650^{\circ}C$ for 30 min, dense and single phase perovskite films were obtained. Dielectric constant and loss tangent of the film were 239 and 0.01 at 1 kHz, respectively.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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• pp.35-36
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• 2006

The influence of the concentration of precursor solution and the number of solution coatings on the densification of the Pb($Zr_xTi_{1-x}$)$O_3$(PZT) thick films was studied. PZT powder and PZT precursor solution were prepared by sol-gel method and PZT thick films were fabricated by the screen-printing method on the alumina substrates. The powder and solution of composition were PZT(70/30) and PZT(30/70), respectively. The coating and drying procedure was repeated 4 times. And then the PZT precursor solution was spin-coated on the PZT thick films. A concentration of a coating solution was 0.5 to 2.0 mol/L[M] and the number of coating was repeated from 0 to 6. The relative dielectric constant of the PZT thick film was increased with increasing the number of solution coatings and the thick films with 15M, 6-time coated showed the 698. The remanent polarization of the 1.5M, 6-time coated PZT thick films was 38.3 ${\mu}C/cm^2$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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• pp.455-458
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• 2001

The thin films of high pemitivity in ferroelectric materials using a capacitor are applied to DRAMs and FRAMs. (Ba, Sr)$TiO_3$ thin films as ferroelectric materials were prepared by the sol-gel method and made by spin-coating on the Pt/Ti/$SiO_2/Si$ substrate at 4,000 [rpm] for 10 seconds. The devices of BST thin films to composite $(Ba_{0.7},Sr_{0.3})TiO_3$ were fabricated by changing of the depositing layer number on $Pt/Ti/SiO_2/Si$ substrate. The thin film capacitor to be ferroelectric devices was investigated by structural and electrical properties. The thickness of BST thin films at each coating numbers 3, 4 and 5 times was $2500[\AA]$, $3500[\AA]$, $3800[\AA]$. The dielectric factor of thin film when the coating numbers were 3, 4 and 5 times was 190, 400 and 460 on frequency l[MHz]. The dielectric loss of BST thin film was linearly increased by increasing of the specimen area.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집
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• pp.455-458
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• 2001

The thin films of high permitivity in ferroelectric materials using a capacitor are applied to DRAMs and FRAMs. (Ba, Sr)TiO$_3$ thin films as ferroelectric materials were prepared by the sol-gel method and made by spin-coating on the Pt/Ti/SiO$_2$/Si substrate at 4,700 [rpm] for 10 seconds. The devices of BST thin films to composite (Ba$\_$0.7/Sr$\_$0.3/)TiO$_3$ were fabricated by changing of the depositing layer number on Pt/Ti/SiO$_2$/Si substrate. The thin film capacitor to be ferroelectric devices was investigated by structural and electrical properties. The thickness of BST thin films at each coating numbers 3, 4 and 5 times was 2500[${\AA}$], 3500[${\AA}$], 3800[${\AA}$]. The dielectric factor of thin film when the coating numbers were 3, 4 and 5 times was 190, 400 and 460 on frequency 1[MHz]. The dielectric loss of BST thin film was linearly increased by increasing of the specimen area.

• E2M - 전기 전자와 첨단 소재
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• 제10권2호
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• pp.134-140
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• 1997

PbTiO$_{3}$-PbZrO$_{3}$-Pb(Ni$_{1}$3/Nb $_{2}$3/O$_{3}$)(PZT-PNN) thin films were prepared from corresponding metal organics partially stabilized with diethanolamine by the sol-gel spin coating method. Each mol rates of PT:PZ:PNN solutions were #1(50:40:10), #2(50:30:20), #3(45:35:20) and #4(40:40:20), respectively. The spin-coated PZT-PNN films were sintered at the temperature from 500.deg. C to 600.deg. C for crystallization. The P-E hysteresis curve was drawn by Sawyer-Tower circuit with PZT-PNN film. The coercive field and the remanent polarization of #4(40:40:20 mol%) PZT-PNN film were 28.8 kV/cm and 18.3 .mu.C/cm$^{2}$, respectively. Their dielectric constants were shown between 128 and 1120, and became maximum value in MPB(40:40:20 mol%). The leakage currents of PZT-PNN films were about 9.4x 10$^{-8}$ A/cm$^{2}$, and the breakdown voltages were about 0.14 and 1.1 MV/cm. The Curie point of #3(45:35:20 mol%, sintered at 600.deg. C) film was 330.deg. C.

• E2M - 전기 전자와 첨단 소재
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• 제8권3호
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• pp.261-266
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• 1995

In this study, PZT solutions added impurities of Yttrium acetate were prepared by sol-gel processing and were deposited on Pt/ $SiO_{2}$/Si substrates at 5000 rpm for 20 sec. using spin-coating method. Coated films were annealed at 700-750.deg. C for 30 min. using conventional furnace method. Variations of the crystallographic structure and microstructure of PZT thin films with adding impurities were observed using XRD and SEM, and the electrical properties, such as relative permittivity, tan .delta., hysteresis curves and leakage currents, were measured. As the yttrium contents were increased, the remanent polarization and coercive field were decreased. Variations of remanent polarizations and coercive fields of pure and yttrium doped specimens according to polarization reversal cycles were observed using hysteresis measurement. PZT thin films added $Y^{3+}$ ions were completely crystallized at 750.deg. C. $Y^{3+}$ ions, as donor impurity, substituted Pb.sup 2+/ ions located at A-site of perovskite structure. By substitution of $Y^{3+}$ ions, leakage currents became less by decreasing the space charges. Degradation of remanent polarizations of Yttrium added specimens after fatigue was not observed and coercive fields increased more than those of pure PZT thin films.

• E2M - 전기 전자와 첨단 소재
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• 제9권2호
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• pp.132-137
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• 1996

Pb(Zr$_{x}$Ti$_{1-x}$ )O$_{3}$ solutions prepared by sol-gel processing with different Zr/Ti ratio were coated on Pt/SiO$_{2}$/Si substrates using spin coating method. Coated films were annealed by rapid thermal annealing at 650.deg. C for 20sec to fabricate Pb(Zr, Ti)O$_{3}$ ferroelectric thin films. Electrical properties of the films such as dielectric constant and loss, ferroelectric hysteresis, fatigue, switching time, and leakage current were measured. Hysteresis of the films with different Zr/Ti ratio yield Pr ranging 10-21.mu.C/cm$^{2}$, E$_{c}$ ranging 37.5-137.5kV/cm. Hysteresis curve was changed from square-type to slim type according to increasing Zr contents. Switching time was faster than 180ns, and leakage current was about 20.mu.A/cm$^{2}$. The film underwent above 10$^{8}$ cycles of reversed polarization showed fatigue with increased coercive field and decreased remnant polarization.tion.

• 한국세라믹학회지
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• 제36권9호
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• pp.893-900
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• 1999

Silica films were prepared on Si single crystal substrates by sol-gel process using TEOS as starting materials. Films were fabricated by a spin coating technique. Sol solutions were prepared by varying the compositions of CH3OH, H2O and DMF with fixed molar ratio of TEOS=1, HCl=0.05(mol). Wetting behavior viscosity of solutions gelation time thickness of films and cracking behavior were investigated with the various solution compositions. Wetting behaviors of solutions depended on the solution compositions mixing method and mixing rate. The optimum composition of sol was TEOS : DMF ; CH3OH: H2O :HCl=1:2:4:4:0.05(mol) and the mixing rate of solution was optimized at 1 ml/min. Viscosity of solutions were controlled by choosing a reaction time(elapsed time after mixing) at a room temperature so that we could get up to 800nm thick film The surface roughness was getting poor when thickness of films was thicker than 500nm. Thickness of coated films were increased with decreasing amount of CH3OH. The best surface roughness was obtained at the content of CH3OH 4 mol. The shortest gelation time was obtained with the content of CH3OH 8 mol. Crack-free filkms were fabricated when sintered at 500$^{\circ}C$ for 1 hr with heating rate of 0.6$^{\circ}C$/min.