• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 D
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• pp.1456-1458
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• 1998

The $(Sr_{1-x}Ca_x)TiO_3(SCT)$ thin films were deposited at various substrate temperature using rf magnetron sputtering method on optimized Pt-coated electrodes ($Pt/TiN/SiO_2/Si$). The dielectric constant changes almost linearly in the temperature region of $-80{\sim}+90[^{\circ}C]$, the temperature characteristics of the dielectric loss exhibited a stable value within 0.1. The capacitance characteristics appears a stable value within ${\pm}5$[%]. The drastic decrease of dielectric constant and increase of dielectric loss in SCT thin films is observed above 200[kHz]. Dielectric constant of SCT thin films deposited on Si wafer substrate are larger with the increase of deposition temperature.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 춘계학술대회 논문집 센서 박막재료 반도체재료 기술교육
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• pp.78-81
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• 2002

Ferroelectric thin film is a very attractive material for the tunable microwave device applications such as electronically tunable mixers, delay lines, filters and phase shifters. Thin films of $Pb_{x}Sr_{1-x}TiO3(PST)$ were fabricated onto Pt/Ti/SiO2/Si substrate by the sol-gel method. We have investigated the structural and dielectric properties of PST(50/50) thin films for tunable microwave device applications. The PST thin films show typical polycrystalline structure with a dense microstructure without secondary phase formation. Dielectric properties of PST films are strongly dependent on annealing temperature. The dielectric constants, loss and tunability of the PST (50/50) thin films were 404, 0.023 and 51.73 %, respectively.

• 한국전기전자재료학회논문지
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• 제29권10호
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• pp.620-624
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• 2016

Ferroelectric $Pb(Zr_{0.52}Ti_{0.48})O_3$ (PZT) films were deposited on SrTiO3(100) substrate by using conductive $SrRuO_3$ films as underlayer and their structural and ferroelectric properties were investigated. PZT films were grown in (00l) orientation on well lattice-matched pseudo-cubic $SrRuO_3$ films. Thickness dependence of ferroelectric and electrical properties of PZT films was investigated. PZT film with 400 nm thickness showed a remanent polarization ($P_r$) of $29.0{\mu}C/cm^2$ and coercive field ($E_c$) of 83 kV/cm, and $P_r$ decreased and $E_c$ increased with thickness reduction. The dielectric constant for PZT films showed gradual decrease with thickness reduction. Breakdown field of PZT films did not show the thickness dependence and displayed as high value as 1 MV/cm.

• The Korean Journal of Ceramics
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• 제6권4호
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• pp.333-338
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• 2000

$Ba_{0.7}Sr_{0.3}TiO_3$(BST) thin films were deposited simultaneously on various electrodes and buffers by the sputtering technique. When the substrate temperature was varied, the BST thin film on each electrode showed good crystallinity above $550^{\circ}C$ as revealed by X-ray diffraction measurements. The surface morphology, determined by atomic force microscopy, indicated that the roughness of BST thin films on $RuO_2$was substrate dependent. However, BST thin films on Ru electrodes are smoother and showed no substrate dependence, probably because the precursor surface diffusion length was greater than the sinusoidal perturbations of the wavelength.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 춘계학술대회 논문집 센서 박막재료 반도체재료 기술교육
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• pp.16-19
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• 2002

(Ba,Sr)TiO3(BST) thin film is an attractive material for the application in high-density dynamic random access memories (DRAMs) because of the high relative dielectric constant and small variation in dielectric properties with frequency. In this study, (Ba0.6,Sr0.4)TiO3 thin films on Pt/Ti/SiO2/Si substrates were deposited by a sol-gel method and the CF4/Ar inductively coupled plasma (ICP) etching behavior of BST thin films had been investigatedby varying the process parameters such as chamber pressure, ICP power, and substrate bias voltage. To analysis the composition of surface residue following etching BST films etched with different Ar/CF4 gas mixing ratio were investigated using x-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometer (SIMS).

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부 C
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• pp.740-742
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• 1998

In this paper, we described the effect of rapid thermal annealing on the electrical properties of interfacial layer between various top electrodes and $(Ba_{0.5}Sr_{0.5})TiO_3$ thin films. BST thin films were fabricated on Pt/TiN/$SiO_2$/Si substrate by RF magnetron sputtering technique. AI, Ag, and Cu films for the formation of top electrode were deposited on BST thin films by thermal evaporator. Top electrodes/BST/Pt capacitor annealed with rapid thermal annealing at various temperature. In $(Ba_{0.5}Sr_{0.5})TiO_3$ thin films with Cu top electrode annealed at $500^{\circ}C$, the dielectric constant was measured to the value of 366 at 1.2 [kHz] and the leakage current was obtained to the value of $5.85{\times}10^{-7}\;[A/cm^2}$ at the forward bias of 2 [V].

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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• pp.565-568
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• 2004

An alkoxide-based sol-gel method was used to fabricate $Ba_{0.6}Sr_{0.4}TiO_3$ thin films doped by Bi from 5 to 20 mol% on a Pt/Ti/SiO2/Si substrate. The structural and dielectric properties of BST thin films were investigated as a function of Bi dopant concentration. The dielectric properties of the Bi doped BST films were strongly dependent on the Bi contents. The dielectric constant and dielectric loss of the films decreased with increasing Bi content. However, the leakage current density of the 10 mol% Bi doped $Ba_{0.6}Sr_{0.4}TiO_3$ thin film showed the lowest value of 5.13 10-7 at 5 V. The figure of merit (FOM) reached a maximum value of 32.42 at a 10 mol% Bi doped $Ba_{0.6}Sr_{0.4}TiO_3$ thin films. The dielectric constant, loss factor, and tunability of the 10 mol% Bi doped $BBa_{0.6}Sr_{0.4}TiO_3$ thin films were 333,0.0095, and 31.1%, respectively.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 춘계학술대회 논문집 반도체 재료 센서 박막재료 전자세라믹스
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• pp.18-21
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• 2004

An alkoxide-based sol-gel method was used to fabricate $Ba_{0.6}Sr_{0.4}TiO_3$ thin films doped by Bi from 5 to 20 mol% on a $Pt/Ti/SiO_2/Si$ substrate. The structural and dielectric properties of BST thin films were investigated as a function of Bi dopant concentration. The dielectric properties of the Bi doped BST films were strongly dependent on the Bi contents. The dielectric constant and dielectric loss of the films decreased with increasing Bi content. However, the leakage current density of the 10 mol% Bi doped $Ba_{0.6}Sr_{0.4}TiO_3$ thin film showed the lowest value of $5.13{\times}10^{-7}\;A/cm^2$ at 5 V. The figure of merit (FOM) reached a maximum value of 32.42 at a 10 mol% Bi doped $Ba_{0.6}Sr_{0.4}TiO_3$ thin films. The dielectric constant, loss factor, and tunability of the 10 mol% Bi doped $Ba_{0.6}Sr_{0.4}TiO_3$ thin films were 333, 0.0095, and 31.1%, respectively.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.60-60
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• 2008

We manufactured Liquid Crystal Polymer (LCP) and (1-x)$BaTiO_3-xSrTiO_3$(BST) ceramic composites and investigated dielectric properties to use as embedded capacitor in printed circuit boards and replace LTCC substrates. The dielectric properties of these composites are varied with volume fraction of BST and ratios of BT/ST. Dielectric constants are in the range of 3~28. In addition, we could get low TCC and High Q value that could not achieve in other ceramic-polymer composites. Especially, in composite with x=0.4 and 50vol% BST, the dieletric constant and Q-value are 27 and 300, respectively. And more TCC is -116~145ppm/$^{\circ}C$ in the temperature range of -55~$125^{\circ}C$. We think that this composites can be used high-Q substrate material like LTCC and embedded temperature compensation capacitor in printed circuit boards.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 춘계학술대회 논문집 센서 박막재료 반도체재료 기술교육
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• pp.103-106
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• 2002

The applicability of models based on fractal morphology to characterize $(Ba\;Sr)TiO_{3}$ thin film surfaces was investigated. The fractal morphology of coated barium strontium titan oxide thin film surfaces was described using fractal dimension from scanning electro microscopy image. The $(Ba\;Sr)TiO_{3}$ coating were deposited on silicon wafers using $(Ba\;Sr)TiO_{3}$ solution and spin coater. BST solution was composited by mol ratio, and then spin-coated from 3 times to 5 times coating on $Pt/SiO_{2}/Si$ substrate. Qualitative thin film analysis was performed with scanning electro microscopy (SEM), and surfaces parameters such as average grain diameter, roughness exponent and fractal dimension were determined.