• Journal of Korean Vacuum Science & Technology
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• v.4 no.1
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• pp.6-10
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• 2000

Ferroelectric YMnO$_3$ thin films were deposited on $Y_2$O$_3$/si(100) substrates by metalorganic chemical vapor deposition. The YMnO$_3$ thin films annealed in vacuum ambient (100 mTorr) above 75$0^{\circ}C$ show hexagonal structured YMnO$_3$. However, the film annealed in oxygen ambient shows poor crystallinity, and the second phase as $Y_2$O$_3$ and orthorhombic-YMnO$_3$ were shown. The annealing ambient and pressure on the crystallinity of YMnO$_3$ thin films is very important. The C-V characteristics have a hysteresis curve with a clockwise rotation, which indicates ferroelectric polarization switching behavior. When the gate voltage sweeps from +5 to 5 V, the memory window of the Pt/YMnO$_3$/Y$_2$O$_3$/Si gate capacitor annealed at 85$0^{\circ}C$ is 1.8 V. The typical leakage current densities of the films annealed in oxygen and vacuum ambient are about 10$^{-3}$ and 10$^{-7}$ A/cm$^2$ at applied voltage of 5 V.

• Journal of the Korean Ceramic Society
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• v.30 no.6
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• pp.510-516
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• 1993

$PbTiO_3$ thin films have been formed by rapid thermal annealing(RTA) of $TiO_2$/Pb/$TiO_2$ multilayer films deposited on Si wafers by RF sputtering. Based on the optimal depositon conditions of TiO2 and Pb, $TiO_2$/Pb/$TiO_2$ three layers were deposited for 900$\AA$ each. These films were subjected to RTA process at the temperatures ranging from $400^{\circ}C$ to $900^{\circ}C$ for 30 seconds in air, and were analyzed by X-ray diffraction and transmission electron microscopy to investigate the phases and the microstructures. As a result, perovskite $PbTiO_3$ phases was obtained above $500^{\circ}C$ with the trace of unreacted $TiO_2$. RBS analysis revealed the anisotropic behavior of diffusion that the diffusivity of Pb to the bottom $TiO_2$ layer was faster than that of Pb to the top $TiO_2$ layer. The amorphous Pb-silicate was formed between film and Si substrate due to the diffusion of Pb, but Pb-silicate existed locally at the interface and the amount of that phase was very small. Therefore the effect of bottom $TiO_2$ layer as a diffusion barrier was confirmed. $PbTiO_3$ films formed by current technique showed a relative dielectric constant of 60, and the maximum breakdown field reached 170kV/cm.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.9
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• pp.745-750
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• 2000

The (S $r_{0.85}$C $a_{0.15}$) Ti $O_3$(SCT) thin films are deposited on Pt-coated electrode (Pt/TiN/ $SiO_2$/Si) using RF sputtering method at various deposition temperature. The crystallinity of SCT thin films were increased with increase of deposition temperature in the temperature range of 200~500[$^{\circ}C$]. Also, the composition of SCT thin films were closed to stoichiometry (1.080~1.111 in A/B ratio). V-I characteristics of SCT thin films show the increasing leakage current with the increases of deposition temperature. The conduction mechanism of the SCT thin films observed in the temperature range of 25~100[$^{\circ}C$] can be divided into four regions with different mechanism by the increasing current. The region I below 0.8[MV/cm]shows the ohmic conduction. The region II between 0.9~2[MV/cm] is in proportion to J∝ $E^{1.5}$ , the region III between 2~4[MV/cm] can be explained by the Child’s law, and the region IV above 4[MV/cm]is dominated by the tunneling effect.ect.

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

• Bulletin of the Korean Chemical Society
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• v.28 no.9
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• pp.1463-1466
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• 2007

Single phases of multi-component oxides films, ZrTiO4 and Ta2Zr6O17, could be synthesized by using the combinatorial approach through surface sol-gel route, coating the appropriate mole ratio of 100 mM zirconium butoxide, tantalum butoxide and titanium butoxide precursors on Pt/Ti/SiO2/Si (100) substrate, following pyrolysis at 450 oC, and annealing them at 770 oC. Both the films and bulks of ZrTiO4 and Ta2Zr6O17 showed very stable dielectric properties in temperature range, ?140 to 60 oC, and frequency range, 100 Hz to 1 MHz, promising their applications in wide range of temperatures and frequencies. The dielectric constants of the films were lower and a little more dependent on frequency than those of the bulks. The reduction of dielectric property in the film was mainly due to the interfacial effects that worked as series and parallel-connected capacitances toward the substantial film capacitance.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.4
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• pp.265-271
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• 2003

Ferroelectric lanthanum-substituted Bi$_4$Ti$_3$O$_{12}$(BLT) thin films were fabricated by spin-coating onto a Pt/Ti/SiO$_2$/Si substrate by metalorganic decomposition technique. The grain size in BLT thin films were prepared with controlled by various drying process. The effect of grain size on the crystallization and ferroelectric properties were investigated by x-ray diffraction and field emission scanning electron microscope. The dependence of crystallization and electrical properties are related to the grain size in BLT thin films with different drying temperature. The remanent polarization of BLT thin film increases with the increasing grain size. The value of 2P$_{r}$ and E$_{c}$ of BLT thin film dried at 45$0^{\circ}C$ were 25.9 $\mu$C/$\textrm{cm}^2$ and 85 kV/cm, respectively. The BLT thin film with larger grain size has better fatigue properties. The fatigue properties revealed that small grained film showed more degradation of switching charge than large grained films.lms.s.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.10
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• pp.559-563
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• 2000

The $(Sr_{1-x}Ca_x)TiO_3(SCT)$ thin films are deposited on Pt-coated(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%]. Also the composition of SCT thin films were closed to stoichiometry(1.081∼1.117 in A/B/ ratio). 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 2000[kHz]. The current-voltage characteristics of SCT15 thin films showed the increasing leakage current as the measuring temperature increase.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.264-264
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• 2007

$B_2Mg_{2/3}/Nb_{4/3}O_7\;(B_2MN)$ thin films and $Bi_{3/2}MgNb_{3/2}O_7\;(B_{1.5}MN)$ thin films were deposited as a function of various deposition temperatures on Pt/$TiO_2/SiO_2$/Si substrates by radio frequency magnetron sputtering system. Both of their thin films are shown to crystalline phase at $500^{\circ}C$, deposition temperature, using 100W RF power. The composition of them and structural micro properties are investigated by RBS spectrum and SEM, AFM. 200 nm-thick $B_2MN$ thin films were deposited at room temperature had capacitance density of $151nF/cm^2$ at 100kHz, dissipation factor of 0.003 and had capacitance density of $584nF/cm^2$ at 100kHz, dissipation factor of 0.0045 at $500^{\circ}C$ deposition temperature. Both of their dielectric constant deposited at room temperature and at $500^{\circ}C$ were each approximately 40 and 100.

• Journal of the Korean Vacuum Society
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• v.18 no.6
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• pp.435-439
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• 2009

The reason of lowering the dielectric constant of SiOC film was studied using parameters obtained from C-V measurement and refractive index. SiOC film was formed by the force of ionic bonding during the recombination of dissociated gases. Generally, the dielectric constant was obtained from the square of the refractive index or C-V measurement using the metal/insulator/Si structure. The dielectric constant consists of the ionic and electronic elements. It was researched about the dielectric constant of SiOC film using the average of the ionic and electronic elements. The dielectric constant decreased after annealing process. As deposited films trended toward the dielectric constant consisted of most ionic elements, on the other hand, annealed films mostly consisted of electronic elements. Because the effect of ionic elements reduced after annealing. Consequently, it was found that the electronic effect of SiOC film increased and the ionic effect of SiOC film decreased by the after-annealing.

• Journal of Korean Ophthalmic Optics Society
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• v.3 no.1
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• pp.237-242
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• 1998

A transparent and colorless $80SiO_2-20TiO_2$(mol%) thin films on soda-lime-silica slide glass and sapphire substrate were obtained by spin-coating technique using tetraethyl orthosilicate and titanium trichloride as starting materials. The prepared film annealed at $750^{\circ}C$ showed a high transmittance and a low reflectance. For the $SiO_2-TiO_2$ films on slide glasses, a strong interaction between the sodium ion and oxygens is properbly the origin of the good stability to the high temperature and the high humidity.