• Proceedings of the Korean Magnestics Society Conference
• /
• 2008.12a
• /
• pp.293.2-293.2
• /
• 2008

• Proceedings of the Korean Magnestics Society Conference
• /
• 2008.12a
• /
• pp.87.1-87.1
• /
• 2008

• Korean Journal of Materials Research
• /
• v.3 no.6
• /
• pp.632-637
• /
• 1993

The optical properties and electrochromism of amorphous $WO_3$ thin films were studied. $WO_3$ thin films with thickness of 3000$\AA$~6000$\AA$ were deposited by vacuum evaporat.ion. All these films were transparent and found to be amorphous in structure by X-ray diffraction analysis and the visible wave length refractive indices were found to be between 1.9 and 2.1 and the optical energey gap to be 3.25 eV. Electrochromic devices were made consisting of IT0 transparent electrode, $WO_3$ thin films, $LiCIO_4$- propylene carbonate and Pt counter electrode. In terms of their operation, the amorphous $WO_3$ films were colored blue by a double injection of electrons from the transparent electrode and lithium ions from the $LiCIO_4$-propylene carbonate organic electrolyte and made colorless by electrochemical oxidation reaction. The electrochromic properties of $WO_3$ thin films including coloration and bleaching, optical density and response time were all found to be strongly dependent on the film deposition condition, electrolyte concentration, sheet resistance of the transparent electrode and applied voltage.

• Korean Journal of Materials Research
• /
• v.19 no.2
• /
• pp.90-94
• /
• 2009

The development of low-k materials is essential for modern semiconductor processes to reduce the cross-talk, signal delay and capacitance between multiple layers. The effect of the $CH_4$ concentration on the formation of SiOC(-H) films and their dielectric characteristics were investigated. SiOC(-H) thin films were deposited on Si(100)/$SiO_2$/Ti/Pt substrates by plasma-enhanced chemical vapor deposition (PECVD) with $SiH_4$, $CO_2$ and $CH_4$ gas mixtures. After the deposition, the SiOC(-H) thin films were annealed in an Ar atmosphere using rapid thermal annealing (RTA) for 30min. The electrical properties of the SiOC(-H) films were then measured using an impedance analyzer. The dielectric constant decreased as the $CH_4$ concentration of low-k SiOC(-H) thin film increased. The decrease in the dielectric constant was explained in terms of the decrease of the ionic polarization due to the increase of the relative carbon content. The spectrum via Fourier transform infrared (FT-IR) spectroscopy showed a variety of bonding configurations, including Si-O-Si, H-Si-O, Si-$(CH_3)_2$, Si-$CH_3$ and $CH_x$ in the absorbance mode over the range from 650 to $4000\;cm^{-1}$. The results showed that dielectric properties with different $CH_4$ concentrations are closely related to the (Si-$CH_3$)/[(Si-$CH_3$)+(Si-O)] ratio.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2010.06a
• /
• pp.313-313
• /
• 2010

$BiFeO_3$ (BFO), when forming a solid solution with $BaTiO_3$ (BTO), shows structural transformations over the entire compositional range, which not only gives a way to increase structural stability and electrical resistivity but also applies a means to have better ferromagnetic ordering. In this respect, we have prepared and studied 0.8 BFO-0.2 BTO thin films on Pt(111)/$TiO_2/SiO_2$/Si substrates by pulsed laser deposition. Various deposition parameters, such as deposition temperature and oxygen pressure, have been optimized to get better quality films. Based on the X-ray diffraction results, thin films were successfully deposited at the temperature of $700^{\circ}C$ and an oxygen partial pressure of 10mTorr and 330mTorr. The dielectric, ferroelectric, and magnetic properties have then been characterized. It was found that the films deposited under lower and higher oxygen pressure corresponded to lower leakage current. Magnetism measurement showed an induced ferromagnetism. The microstructures associated with the magnetic and dielectric properties of this mixed-perovskite solid solutions were observed by transmission electron microscopy, which revealed the existence of complicated ferroelectric domains, suggested that the weak spontaneous magnetization was closely associated with the decrease in the extent of rhombohedral distortion by a partial substitution of $BaTiO_3$ for $BiFeO_3$.

• Electrical & Electronic Materials
• /
• v.10 no.2
• /
• pp.134-140
• /
• 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.

• Journal of Sensor Science and Technology
• /
• v.29 no.4
• /
• pp.232-236
• /
• 2020

Three-dimensional (3D) multilayered Pt electrodes were fabricated to develop a porous electrode using a pattern-transfer printing process. The Pt thin films were deposited using a transferred sputtering pattern having a 250 nm line width on the substrate, and the uniform line patterns were efficiently transferred using our proposed method. Temperature-programmed desorption (TPD) analyses were used to evaluate the porosity of the electrodes. It was possible to distinguish between two resolved maxima at 168 and 227 ℃, which could be described in terms of desorption reactions on the Pt (111) planes. The results of the TPD analysis of the 3D and multilayered Pt electrodes prepared through transfer printing were compared to those of an electrode fabricated through screen printing using a commercial Pt-carbon paste commonly used as porous electrodes. It was confirmed that the 3D multilayered electrodes exhibited a desorption concentration approximately 100 times higher than that of the Pt-carbon composite electrode, and the desorption concentration increased by approximately 0.02 mg/mol per layer. The 3D multilayered electrode effectively functions as a porous electrode and a catalyst.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.8 no.2
• /
• pp.233-239
• /
• 1998

SiC thin films were deposited by chemical vapor deposition method using tetramethylsilane (TMS) and hexamethyldisilane (HMDS). The chamber pressure during the deposition was kept at about 1 torr. Precursor was transported to the reaction chamber by $H_2$gas and SiC deposition was carried out at the reaction temperature of $1200^{\circ}C$. Si-wafer masked with tantalum and MgO single crystal covered with platinum and molybdenum were used as substrates. The selectivity of SiC deposition was observed by comparing the microstructure between metal (Ta, Pt, and Mo) surfaces and substrate surfaces (Si and MgO). The deposited films were identified as the $\beta-SiC$ phase by X-ray diffraction pattern. Also, the deposition -behavior of SiC on each surface was investigated by the scanning electron microscope analysis.

• Journal of the Korean Ceramic Society
• /
• v.38 no.1
• /
• pp.39-44
• /
• 2001

솔-젤법으로 S $r_{0.9}$B $i_{2.1}$T $a_2$$O_{9}$ stock solution을 합성하고, Ir $O_2$/ $SiO_2$/Si 및 기판 위에 스핀코팅법으로 약 2000$\AA$ 정도의 두께를 가지고 SBT 박막을 제조하였다. Pt/Ti $O_{x}$ 전극을 사용한 SBT 박막과 비교하였을 때 Ir $O_2$전극을 사용한 SBT 박막의 경우 더 낮은 급속 열처리 온도 즉, 72$0^{\circ}C$에서 형석상에서 층상 페롭스카이트 상으로의 상전이가 관찰되었다. 그리고, Ir $O_2$전극을 사용한 SBT 박막은 낮은 열처리에서 결정성장이 이루어졌다. Ir $O_2$전극을 사용한 SBT 박막은 $650^{\circ}C$에서 열처리하였을 때 포화된 이력곡선을 얻었지만, Pt/Ti $O_{x}$ 전극을 사용한 SBT 박막은 $700^{\circ}C$에서 열처리하였을 때 이력곡선이 관찰되었다. Ir $O_2$전극을 사용한 SBT 박막은 $700^{\circ}C$의 열처리에서 8.79 $\mu$C/$ extrm{cm}^2$ (3V)의 2Pr 값을 나타내었다.나타내었다.다.

• Proceedings of the KIEE Conference
• /
• 1997.07d
• /
• pp.1491-1493
• /
• 1997

In this study, Sol-Gel derived $Ba_{0.7}Sr_{0.3}TiO_3$ (BST(70/30)) thin films were investigated. The stock solution of BST were fabricated and spin-coated on the Pt/Ti/$SiO_2$/Si and ITO/glass substrates. The coated specimen were dried at $300^{\circ}C$ and finally annealed at $650{\sim}750^{\circ}C$. To analyse crystallization condition and microstructural morphology for different substrates, XRD, and SEM analysis were processed. In the BST(70/30) composition. dielectric constant and loss characteristics measured at 1kHz were 173, 0.01% for Pt/Ti/$SiO_2$/Si substrates and 181, 0.019% for ITO/glass substrates, respectively.