• Journal of the Microelectronics and Packaging Society
• /
• v.11 no.3 s.32
• /
• pp.91-97
• /
• 2004

PBT thin films were formed by rf-magnetron sputtering on $Pt/Ti/SiO_2/Si$ substrate. Bulk-PZT target containing $5\%$-excess PbO was used. After PZT thin films had been deposited at room temperature, remaining portion of the thin film was formed by in-situ process. The ferroelectric perovskite phase was formed at $650^{\circ}C$. The leakage current property was improved dramatically by 2-step sputtering, and in the sample containing optimum thickness of room temp.-layer very low leakage current of $2{\times}10^{-7}A/cm^2$ was shown. As a result of the investigation on the leakage current mechanism, the electrical conduction mechanism in all PZT thin films formed by several conditions was confirmed as bulk-limited mechanism.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2011.05a
• /
• pp.30.1-30.1
• /
• 2011

Multiferroic thin films with composition $0.9BiFeO_3-0.1Ba(Cu_{1/3}Nb_{2/3})O_3$ were epitaxially grown by pulsed laser deposition on $SrRuO_3(001)/SrTiO_3$ (000) substrate $0.9BiFeO_3-0.1Ba(Cu_{1/3}Nb_{2/3})O_3$, which is assumed to be morphotropic phase boundary (MPB), that showed superior dielectric, ferroelectric and magnetic properties in our study on polycrystalline films. The structures of epitaxially grown films were characterized by means of XRD. From P-E measurements, samples exhibited typical ferroelectric hysteresis loops and large remnant polarization, whose value is much larger than those of pure BFO film. The enhancement of dielectric, ferroelectric, magnetic properties was attributed to the structural distortion induced by the BCN addition and the high physical stress effect.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.08a
• /
• pp.361-361
• /
• 2012

PZT (Pb(Zr,Ti)O3) thin films have been used widely in the MEMS application, due to their inherent ferroelectric and piezoelectric properties. Such ferroelectricity induces much higher dielectric constants compared to those of the nonperovskite materials. In this work, the PZT thin films were deposited onto Indium-Tin-oxide (ITO) substrates through the spin-coating of PZT sols. The deposited PZT thin films were characterized in terms of the electrical and optical properties with special emphases on conductivity and optical constants. The detailed analysis techniques incorporate the dc-based current-voltage characteristics for the electrical properties, spectroscopic ellipsometry for optical characterization, atomic force microscopy for surface morphology, X-ray Photoelectron Spectroscopy for chemical bonding, Energy-dispersive X-ray Spectrometry for chemical analyses and X-ray diffraction for crystallinity. The ferroelectric phenomena were confirmed using capacitance-voltage measurements. The integrated physical/chemical features are attempted towards energy-oriented applications applicable to next-generation high-efficiency power generation systems.

• Korean Journal of Materials Research
• /
• v.10 no.4
• /
• pp.270-275
• /
• 2000

The Pt/YMnO$_3$/Y$_2$O$_3$/Si structure for metal/ferroelectric/insulator/semiconductor(MFIS)-FET was fabricated and effect of $Y_2$O$_3$layer on the properties of MFIS structure was investigated. The $Y_2$O$_3$ thin films on p-type Si(111) substrate deposited by Pulsed Laser Deposition were crystallized along (111) orientation irrespective of the deposition temperatures. Ferroelectric YMnO$_3$ thin films deposited directly on p-type Si (111) by MOCVD resulted in Mn deficient layer between Si and YMnO$_3$. However, YMnO$_3$ thin films having good quality and stoichiometric composition can be obtained by adopting $Y_2$O$_3$ buffer layer. The memory window of the $Y_2$O$_3$thin films with YMnO$_3$ film is greater than that of the YMnO$_3$ thin films without $Y_2$O$_3$ film after the annealing at 85$0^{\circ}C$ in vacuum ambient(100mtorr). The memory window is 1.3V at an applied voltage of 5V.

• Journal of Advanced Marine Engineering and Technology
• /
• v.30 no.8
• /
• pp.927-933
• /
• 2006

The structural and electrical characteristics of PLZT thin films fabricated onto $Pt/IrO_2/Ir/Ti/SiO_2/Si$ substrates by a pulsed laser deposition were investigated to develop the high dielectric thin films for capacitor layer of semiconductor memory devices The slim region 14/50/50 PLZT thin films were fabricated by PLD and estimated the characteristics for memory application 14/50/50 PLZT thin films have crystallize into perovskite structure at the $600^{\circ}C$ deposition temperature, 200 mTorr of oxygen pressure, and 2 $J/cm^2$ of laser energy density. In this condition PLZT thin films had the dielectric constant as high as 985, storage charge density 8.17 ${\mu}C/cm^2$ and charging time 0.20 ns. Leakage current density was less than $10^{-10}A/cm^2$ up to 5 V bias voltage.

• Journal of the Korean Ceramic Society
• /
• v.40 no.2
• /
• pp.153-158
• /
• 2003

Self-patterning of thin films using photosensitive sol solution has advantages such as simple manufacturing process compared to photoresist/dry etching process. In this study,$La_{0.5}SR_{0.5}CoO_3$(LSCO) thin films as an electrode material for ferroelectric memories have been prepared by spin coating method using photosensitive sol solution. La-2methoxyethoxide, Sr-ethoxide, Co-2methoxyethoxide were used as starting materials. As UV exposure time to the LSCO gel thin film increased, the UV absorption peak intensity of metal${beta}$-diketonate decreased due to reduced solubility by M(metal)-O-M bond formation. Solubility difference by UV irradiation on LSCO gel thin film allows to obtain a fine patterning of thin film. The LSCO thin films annealed over$680{\circ}C$ in air showed perovskite phase and the lowest resistivity$(4{ imes}10^{-3}{Omega}cm)$ of the thin films were obtained by annealing at$740{\circ}C$.

• Proceedings of the IEEK Conference
• /
• 2005.11a
• /
• pp.1265-1268
• /
• 2005

In this study, the synthesis and semiconducting properties of cation and defect-doped $KTaO_3$ film is reported. $KTaO_3$ is an important material for optoelectronic and tunable microwave applications. It is an incipient ferroelectric with a cubic structure that becomes ferroelectric when doped with Nb. While numerous studies have investigated the thin-film growth of semiconducting perovskites, little is reported about semiconducting $KTaO_3$ thin films. In this work, the films were grown on (001) MgO single crystal substrates using pulsed-laser deposition. Semiconducting behavior is achieved by inducing oxygen vacancies in the $KTaO_3$ lattice via growth in a hydrogen atmosphere. The resistivity of semiconducting $KTaO_3:Ca$ films was as low as 10cm, and n-type semiconducting behavior was indicated. Hall mobility and carrier concentration were $0.27cm^2/Vs$ and $3.21018cm^{-3}$, respectively. Crystallinity and microstructure of the $KTaO_3:Ca$ films were examined using X-ray diffraction and field-emission scanning microscopy.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2002.11a
• /
• pp.346-349
• /
• 2002

Ferroelectric $Bi_{4-x}Nd_{x}Ti_{3}O_{12}(BNdT)$ thin films with the composition(x=0.75) were prepared on $Pt/Ti/SiO_{2}/Si(100)$ substrate by metal-organic deposition. The films were annealed by various temperatures from 550 to $650^{\circ}C$ and then the electrical and structural characteristics of BNdT films were investigated for the application of FRAM. Electrical properties such as dielectirc constant, 2Pr and capacitance were quite dependent on the thermal heat treatment. The measured 2Pr value on the BNdT capacitor annealed at $650^{\circ}C$ was $56{\mu}C/cm^{2}$ at an applied voltage of 5V. In fatigue characteristics value remained costant up to $8{\times}10^{10}$ read/write switching cycles at a frequency of 1Mhz regardless of annealing temperatures.

• Journal of the Korean Ceramic Society
• /
• v.40 no.4
• /
• pp.398-400
• /
• 2003

The YMnO$_3$ thin films were prepared on platinized-silicon substrates by chemical solution deposition and annealed at 750 to 85$0^{\circ}C$ for 1 h under various oxygen pressures, from 2 mTorr to 760 Torr. Effects of annealing oxygen pressures on the crystallization behavior and electrical properties of YMnO$_3$ thin films were investigated. Crystallinity and c-axis preferred orientation of YMnO$_3$ thin film were improved by decreasing the oxygen pressure but were deteriorated at extremely low oxygen pressure, 2 mTorr. Leakage current density of the YMn03 thin film decreased as the oxygen pressure decreased. The film annealed at 80$0^{\circ}C$ under 2 Torr, which had the best crystallinity and the highest c-axis preferred orientation. showed the best-developed ferroelectric C-V hysteresis.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2007.06a
• /
• pp.202-203
• /
• 2007

Ferroelectric SBT($SrBi_2Ta_2O_9$) thin films were deposited on Pt/Ti/$SiO_2$/Si substrate using R.F. magnetron sputtering method. The ferroelectric and electric characteristics were investigated with various post-annealing of Pt at $200{\sim}600^{\circ}C$. Compared with SBT thin film which had not post-annealed, the electrical properties and crystallizations of the SBT thin films were relatively improved by the post-annealing of Pt bottom electrode. The crystallization were characterized by X-ray diffraction (XRD). The electrical properties characteristics were observed by HP 4192A and precision LC.