• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2005.09a
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• pp.201-212
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• 2005

[ $Epoxy/BaTiO_3$ ] composite embedded capacitor films (ECFs) were newly designed fur high dielectric constant and low tolerance (less than ${\pm}15\%$) embedded capacitor fabrication for organic substrates. In terms of material formulation, ECFs are composed of specially formulated epoxy resin and latent curing agent, and in terms of coating process, a comma roll coating method is used for uniform film thickness in large area. Dielectric constant of $BaTiO_3\;&\;SrTiO_3$ composite ECF is measured with MIM capacitor at 100 kHz using LCR meter. Dielectric constant of $BaTiO_3$ ECF is bigger than that of $SrTiO_3$ ECF, and it is due to difference of permittivity of $BaTiO_3\;and\;SrTiO_3$ particles. Dielectric constant of $BaTiO_3\;&\;SrTiO_3$ ECF in high frequency range $(0.5\~10GHz)$ is measured using cavity resonance method. In order to estimate dielectric constant, the reflection coefficient is measured with a network analyzer. Dielectric constant is calculated by observing the frequencies of the resonant cavity modes. About both powders, calculated dielectric constants in this frequency range are about 3/4 of the dielectric constants at 1 MHz. This difference is due to the decrease of the dielectric constant of epoxy matrix. For $BaTiO_3$ ECF, there is the dielectric relaxation at $5\~9GHz$. It is due to changing of polarization mode of $BaTiO_3$ powder. In the case of $SrTiO_3$ ECF, there is no relaxation up to 10GHz. Alternative material for embedded capacitor fabrication is $epoxy/BaTiO_3$ composite embedded capacitor paste (ECP). It uses similar materials formulation like ECF and a screen printing method for film coating. The screen printing method has the advantage of forming capacitor partially in desired part. But the screen printing makes surface irregularity during mask peel-off, Surface flatness is significantly improved by adding some additives and by applying pressure during curing. As a result, dielectric layer with improved thickness uniformity is successfully demonstrated. Using $epoxy/BaTiO_3$ composite ECP, dielectric constant of 63 and specific capacitance of 5.1nF/cm2 were achieved.

• Proceedings of the Korean Ceranic Society Conference
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• 2002.10a
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• pp.33.2-33
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• 2002

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.2
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• pp.114-121
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• 1996

Thin film Ba$^{0.7}Sr^{0.3}TiO^{3}$ (BST) capacitors were fabricated on SiO$_{2}$/Si substrates by RF magnetron sputtering method and characterized at microwave frequencies ranging from 40 MHz to 1GHz to examine the dielectric dispersion of the capacitors. The BST thin films were electrode material of BST thin films capacitor which is known as one of the best electrode materials for BST films. 50$\AA$-thick titanium (Ti) layers were introduced to increase adhesion between bottom Pt and SiO$_{2}$. The leakage current density of the capacitors was about 1.7${\times}10^{7}A/cm^{2}$ at 1.5V and the dielectric constant was about 140 at 1MHz. Microwave measurement patterns having a coplanar waveguide type were fabricated and their S parameters were measured using network analyzer. After de-embedding parasitic components in microwave measurement patterns nearly frequency-invariant dielectric constant of about 120 was extracted in the measurement range of 40 MHz to 1 GHz.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.11
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• pp.984-989
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• 1998

The ($Sr_{1-x}Ca_x)TiO_3$(SCT) thin films are deposited on Pt-coated electrode($Pt/TiN/SiO_2/Si$) using RF sputtering method with substitutional contents of Ca. The maximum grain of thin films is obtained by substitution of Ca at 15[mol%]. All SCT thin films had (111) preferred orientation. The dielectric constant was increased with increasing the substitutional contents of Ca, while it was decreased if the substitutional contents of Ca exceeded over 15[mol%]. The dielectric constant changes almost linearly in temperature ranges of -80~+90[$^{\circ}C$]. The temperature properties of the dielectric loss have a stable value within 0.02 independent of the substitutional contents of Ca. All SCT thin films used in this study show the phenomena of dielectric relaxation with the increase of frequency, and the relaxation frequency is observed above 200[kHz].

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.1001-1004
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• 2001

The (Sr$_{l-x}$Ca$_{x}$)TiO$_3$(SCT) thin films are deposited on Pt-coated electrode(Pt/TiN/SiO$_2$/Si) using RF sputtering method with substitutional contents of Ca. The maximum grain of thin films is obtained by substitution of Ca at 15[mol%]. The dielectric constant was increased -with increasing the substitutional contents of Ca, while it was decreased if the substitutional contents of Ca exceeded over 15[mol%]. The dielectric constant changes almost linearly in temperature ranges of -80~+90[$^{\circ}C$]. The temperature properties of the dielectric loss have a stable value within 0.02 independent of the substitutional contents of Ca. The current-voltage characteristics of SCT15 thin films showed the increasing leakage current as the measuring temperature increases.ses.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.1
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• pp.128-131
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• 2007

YBaCuO superconducting ceramic thick films were fabricated by chemical process. YBaCuO films have been successfully grown on $SrTiO_3$ substrates without a template layer. The films show poor or non superconductivity although they have excellent crystalline properties. ion channeling measurement made it clear that the strain in the films due to strong chemical bonding between the substrate and epilayer remains, resulting in the poor superconductivity. The X ray diffraction pattern of the YBaCuO thick films contained 90K phase. The self template method have resolved this problem. We obtained high-Jc as-grown YBaCuO on $SrTiO_3$ (100).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.244-247
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• 2002

NdBaCuO thin films were prepared on $SrTiO_{3}$ substrates by RF magnetron sputtering. These as-grown films were classified into 3type. The resistivity of the deposited films are usually lower than of the YBCO film. The Tc (onset) and Tc (R=0) in the optimized thin films are as high as 90 and 80K, respectively. These as-grown films are highly uniform and semi-trans parent and have a room temperature resistivity of $0.3m{\Omega}cm$.

• Journal of the Korean Ceramic Society
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• v.27 no.7
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• pp.841-850
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• 1990

The electrical conductivity of SrTiO3 thick films, which has been prepared by screen printing and sintering on polycrystalline Al2O3 substrates, was determined as a function of oxygen partial pressure and temperature. The data showed that electrical conductivity was proportional to the -1/4th power of the oxygen partial pressure for the oxygen partial pressure range from 10-4-10-8 to 10-20 atm and proportional to Po2+1/4 for the oxygen partial pressure range from 10-6-10-4 to 1atm. And then n-p transition region of electrical conductivity moved to lower oxygen partial pressure region as the sintering temperature of thick film specimens increased under about 140$0^{\circ}C$. These data were consistent with the presence of small amounts of acceptor impurities in SrTiO3 thick film which have been diffused from Al2O3 substrate in the range of solid solubility limit.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05b
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• pp.42-45
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• 2001

The high permittivity are applied to DRAM and FRAM. (Ba,Sr)$TiO_3$ (EST) thin films were prepared by Sol-Gel method. BST solution was made and spin-coated on $Pt/SiO_2/Si$ substrate at 4000 [rpm] for 10 seconds in a time coating. Coated specimens were dried at $90[^{\circ}C]$ for 5 minutes. Coating process was repeated from 3 times to 5 times and then sintered at $750[^{\circ}C]$ for 30 minutes. Each specimen was analyzed structure and electrical characteristics. Thickness of BST ceramics thin films are about 2600-2800[$\AA$] in 3 times. Dielectric constant of thin films was little decreased at 1[KHz]~1[MHz]. Dielectric constant and loss to frequency were 250 and 0.02 in BST3. The property of leakage current was stable When the applied voltage was 0~3[V] Leakage current was $10^{9}\sim10^{11}$[A] at 0~3[V].

• Journal of the Korean Ceramic Society
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• v.27 no.2
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• pp.249-255
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• 1990

High Tc Supperconducting thin films were fabricated by rf magnetron sputtering method. We have successfully controlled the compositions of films by adding sintered CuO pellets on YBa2Cu3O7-x single target. High Tc thin films with large grian size and good crystal habit were obtained by rapid thermal annealing process. The films deposited on SrTiO3(100) single crystal substrate indicated the existence of c-axis prefered orientation confirmed by XRD and SEM analysis. The Tc, zero's of sharp resistive transition for rapid annealed films deposited on polycrystalline YSZ substrate and on SrTiO3(100) single crystal substrate were 79K and 88K, respectively.