• Journal of Magnetics
• /
• v.17 no.2
• /
• pp.78-82
• /
• 2012

CoNiFe(CNF)/$BaTiO_3(BTO)$/CoNiFe(CNF) multilayered thin films were deposited on Pt/Ti/$SiO_2$/Si substrates by using pulsed laser deposition (PLD) system. We fabricated three different thin films of BTO, BTO/CNF and CNF/BTO/CNF for magneto-capacitor and studied their crystalline structure, surface and interface morphology, and magnetic and electrical properties. When three different structures of multilayered thin film were compared, magnetization of CNF/BTO/CNF thin films was decreased by magnetic and dielectric interaction. Also we confirmed that capacitance of CNF/BTO/CNF multilayered thin film was enhanced as being near tetragonal structure with increasing of c/a ratio because of atomic bonding at interface between BTO dielectric and CNF magnetic materials. Finally, we studied the change of the capacitance of CNF/BTO/CNF multilayered thin film with magnetic field for emergence of magnetocapacitance and suggested a possibility of enhanced capacitance.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2002.07a
• /
• pp.301-304
• /
• 2002

We investigated the structural and electrical properties of Ce-doped Ba($Zr_{0.2}Ti_{0.8}$)$O_3$(BCZT) thin films with a mole fraction of x=0.2 and a thickness about 100 nm. BCZT films were prepared on Pt/Ti/$SiO_2$/Si substrate by a RF magnetron sputtering system. We have measured the thickness profile with Ar/$O_2$ ratio and the surface roughness. It was observed that the oxygen gas, which introduced during the film deposition, have an influence on the roughness of the film and the film roughness was reduced by annealing from 2.33 nm to 2.02 m (RMS at $500^{\circ}C$, Ar:6 scrim, $O_2$:6 sccm). We have found that annealing procedure after top electrode deposit can reduce the dissipation factor.

• Proceedings of the KIEE Conference
• /
• 2002.07c
• /
• pp.1476-1478
• /
• 2002

In recent years, the tantalum nitride(TaN) thin-film has been developed for the electronic resistor, inductor and capacitor. In this papers, this study presents the surface profile and sheet-resistance property relationship of reactive-sputtered TaN thin film resistor processed by TaN(tantalum nitride) on alumina substrate. The TCR properties of the TaN films were discussed in terms of crystallization and thin films surface morphology due to annealing temperature. It is clear that the TaN thin-films resistor electrical properties are low TCR related with it's annealing temperature and ambient annealing condition. Respectively, at $300{\sim}400^{\circ}C$ on vacuum and nitrogen annealed thin film resistor having a goof thermal stability and lower TCR properties then as deposited thin films expected for the application to the dielectric material of passive component.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.17 no.9
• /
• pp.947-952
• /
• 2004

Tb-doped lead zirconate titanate(Pb(Zr$\_$0.6/,Ti$\_$0.4/)O$_3$; PZT) thin films on Pt(111)/Ti/SiO$_2$/Si(100) substrates were fabricated by the sol-gel method. The effect on the structural and electrical properties of films measured according to Tb content. The dielectric and ferroelectric properties of Tb-doped PZT thin films were altered significantly by Tb-doping. The PZT thin film with higher dielectric constant and improved leakage current characteristic was obtained by adding 0.3 mol% Tb. The relative dielectric constant and the dielectric loss of the 0.3 mol% Tb-doped PZT thin film were 1611 and 0.024, respectively. Typical value of the swichable remanent poaraization(2Pr) and the coercive filed of the PZT film capacitor for 0.3 mol% Tb-doped were 61.4 ${\mu}$C/cm$^2$ and 61.9 kV/cm, respectively. Tb-doped PZT thin films showed improved fatigue characteristics comparing to the undoped PZT thin film.

• Journal of the Korean Society for Heat Treatment
• /
• v.14 no.5
• /
• pp.292-296
• /
• 2001

In this work, an ultra-high vacuum activated reactive evaporation equipment was built. With reaction of Al and oxygen plasma, $Al_2O_3$ was deposited on the surface of etched Al foil. The chamber was evacuated down to $2{\times}10^{-7}$ torr initially. The Ar and $O_2$ gas introduced into the chamber to maintain $5{\times}10^{-5}$ torr during deposition. Ar gas prevents recombining of the ionized oxygen. Evaporation was maintained by electron beam evaporator continuously. Heating filament and electrode were used in order to generate plasma. The substrate bias of -300V was introduced to accelerate deposition of evaporated Al atoms. The composition and morphology of deposited $Al_2O_3$ films were analyzed by x-ray photoelectron spectroscopy(XPS) and atomic force microscopy (AFM), respectively. The Al oxide was formed on the surface of etched Al foil. According to AFM results, the surface morphology of $Al_2O_3$ film indicates uniform feature. Dielectric characteristic was measured as a function of frequency. Measured withstanding voltage and capacitance were 52V and $24{\mu}F/cm^2$, respectively. The obtained $Al_2O_3$ film shows clean condition without contaminants, which could be adapted to capacitor production.

• Korean Journal of Materials Research
• /
• v.26 no.3
• /
• pp.160-165
• /
• 2016

To increase the capacitance of an Al electrolytic capacitor, the anodic oxide film, $Al_2O_3$, was partly replaced by an $Al_2O_3-ZrO_2$ (Al-Zr) composite film prepared by the vacuum infiltration method and anodization. The microstructure and composition of the prepared samples were investigated by scanning electron microscopy and transmission electron microscopy. The coated and anodized samples showed multi-layer structures, which consisted of an inner Al hydrate layer, a middle Al-Zr composite layer, and an outer $Al_2O_3$ layer. The thickness of the coating layer could go up to 220 nm when the etched Al foil was coated 8 times. The electrical properties of the samples, such as specific capacitance, leakage current, and withstanding voltages, were also characterized after anodization at 100 V and 600 V. The capacitances of samples with $ZrO_2$ coating were 36.3% and 27.5% higher than those of samples without $ZrO_2$ coating when anodized at 100 V and 600 V, respectively.

• The Korean Journal of Ceramics
• /
• v.2 no.2
• /
• pp.95-101
• /
• 1996

Variations of the leakage current behaviors and interface potential barrier $({\Phi}_B)$ of rf-sputter deposited (Ba, Sr)$TiO_3$ (BST) thin films with thicknesses ranging from 20 nm to 150nm are investigated as a function of the thickness and bias voltages. The top and bottom electrodes are dc-sputter-deposited Pt films. ${\Phi}_B$ critically depends on the BST film deposition temperature, postannealing atmosphere and time after the annealing. The postannealing under $N_2$ atmosphere results in a high interface potential barrier height and low leakage current. Maintaining the BST capacitor in air for a long time reduces the ${\Phi}_B$ from about 2.4 eV to 1.6 eV due to the oxidation. ${\Phi}_B$ is not so dependent on the film thickness in this experimental range. The leakage conduction mechanism is very dependent on the BST film thickness; the 20 nm thick film shows tunneling current, 30 and 40 nm thick films show Shottky emission current.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.16 no.5
• /
• pp.361-364
• /
• 2003

It was investigated that the structural and electrical Properties of Ce-doped Ba(Zr$_{x}$Ti$_{1-x}$ )O$_3$ (BCZT) thin films with a mole fraction of x=0.2 and a thickness about 100 nm. BCZT films were prepared on Pt/Ti/SiO$_2$/Si substrate by a RF magnetron sputtering system. We have measured the thickness profile with Ar/O$_2$ ratio and the surface roughness. It was observed that the oxygen gas, which introduced during the film deposition, have an influence on the roughness of the film and the film roughness was reduced by annealing from 2.33 nm to 2.02 nm (RMS at 500 $^{\circ}C$, Ar:6 sccm, $O_2$:6 sccm). It was found that annealing procedure after top electrode deposit can reduce the dissipation factor.

• Proceedings of the KIEE Conference
• /
• 1999.07d
• /
• pp.1553-1555
• /
• 1999

Recently, $SrBi_2Ta_2O_9$(SBT) and $Pb(ZrTi)O_3$(PZT) were much attracted as materials of capacitor for ferroelectric random access memory(FRAM) showing higher read/write speed, lower power consumption and nonvolartility. Bi-layered SBT thin film has appeared as the most prominent fatigue free and low operation voltage for use in nonvolatile memory. To highly integrate FRAM, SBT thin film should be etched. A lot of papers on SBT thin film and its characteristics have been studied. However, there are few reports about SBT thin film due to difficulty of etching. In order to investigate properties of etching of SBT thin film, SBT thin film was etched in $CF_4$/Ar gas plasma using magnetically enhanced inductively coupled plasma (MEICP) system. When $CF_4/(CF_4+Ar)$ is 0.1, etch rate of SBT thin film was $3300{\AA}/min$, and etch rate of Pt was $2495{\AA}/min$. Selectivities of SBT to Pt. $SiO_2$ and photoresist(PR) were 1.35, 0.6 and 0.89, respectively. With increasing $CF_4$ gas, etch rate of SBT thin film and $P_t$ decreased.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.6 no.5
• /
• pp.696-702
• /
• 2002

The BST $({Bal-xSrxTiO_3})$ (50/50) thin film has been grown by RF magnetron reactive sputtering and its characteristics such as crystallization, surface roughness, and electrical properties have been investigated with varying the film thickness. The crystallization and surface roughness of BST thin film are investigated by using XRD and AFM, respectively. The BST thin film annealed at $800^{\circ}C$ for 2 min has pure perovskite structure and good surface roughness of 16.1$\AA$. As the film thickness increases from 80 nm to 240 nm, the dielectric constant at 10 KHz increases from 199 to 265 and the leakage current density at 250 ㎸/cm decreases from $0.779 {\mu}A/{cm^2} to 0.184 {\mu}A/{cm^2}$. In the case of 240 nm-thick BST thin film, the charge storage density and leakage current density at 5V are 50.5 fC/${{\mu}m^2} and 0.182 {\mu}A/{cm^2}$, respectively. The values indicate that the BST thin film is a very useful dielectric material for the DRAM capacitor.