• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.768-771
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• 2004

Pb0.5,Sr0.5TiO3(PST) thin films were deposited on Si with MgO (100) buffer layer by the alkoxide-based sol-gel method. Structural and dielectric properties of PST thin films for the tunable microwave device applications were investigated. For the MgO/Si buffer layer, the PST thin films exhibited highly (100) orientation. The MgO buffer layer affects the stress state of the (100)-oriented PST thin films. The dielectric constant, tunability, and FOM of the highly (100)-oriented PST thin film increased with increasing annealing temperature due to the decrease in lattice distortion. The differences in dielectric properties may be attributed to the change in the film stress. The dielectric constants, dielectric loss and tunability of the PST thin films deposited on the MgO/Si substrates measured at 10 kHz were 822, 0.025, and 80.1%, respectively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.6
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• pp.436-441
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• 1998

$Pt/SrTiO_3/Pb_x(Zr_{0.52}, Ti_{0.48})O_3/SrTiO_3/Si$ structure was prepared by rf-magnetron sputtering method for use in nondestructive read out ferroelectric RAM(NDRO-FEAM). PBx(Zr_{0.52}Ti_{0.48})O_3}$(PZT) and $SrTiO_3$(STO) films were deposited respectively at the temperatures of $300^{\circ}C and 500^{\circ}C$on p-Si(100) substrate. The role of the STO film as a buffer layer between the PZT film and the Si substrate was studied using X-ray diffraction (XRD), Auger electron spectroscopy (ASE), and scanning electron microscope(SEM). Structural analysis on the interfaces was carried out using a cross sectional transmission electron microscope(TEM). For PZT/Si structure, mostly Pb deficient pyrochlore phase was formed due to the serious diffusion of Pb into the Si substrate. On the other hand, for STO/PZT/STO/Si structure, the PZT film had perovskite phase and larger grain size with a little Pb interdiffusion. the interfaces of the PZT and the STO film, of the STO film and the interface layer and $SiO_2$, and of the $SiO_2$ and the Si substate had a good flatness. Across sectional TEM image showed the existence of an amorphous layer and $SiO_2$ with 7nm thickness between the STO film and the Si substrate. The electrical properties of MIFIS structure was characterized by C-V and I-V measurements. By 1MHz C-V characteristics Pt/STO(25nm)/PZT(160nm)/STO(25nm)/Si structure, memory window was about 1.2 V for and applied voltage of 5 V. Memory window increased by increasing the applied voltage and maximum voltage of memory window was 2 V for V applied. Memory window decreased by decreasing PZT film thickness to 110nm. Typical leakage current was abour $10{-8}$ A/cm for an applied voltage of 5 V.

• Proceedings of the Materials Research Society of Korea Conference
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• 1994.05a
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• pp.109-109
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• 1994

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.1
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• pp.7-11
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• 2015

In this study, $Si_3N_4$/SnZnO/AZO/Ag/Ti/ITO multi-layer film were prepared on glass substrate by DC/RF magnetron sputtering method. To prevent interfacial reaction between Ag and ITO layer, Ti buffer layer was inserted. Optical properties and sheet resistance were studied depending on laminating times of each multi-layered film especially in visible ray. The simulation program, EMP (essential macleod program), was adopted and compared with experimental data to expect the experimental result. It was found out that the transmittance of the first stacked $Si_3N_4$/SnZnO/AZO/Ag/Ti/ITO multi-layer film was more than 90%. However, with increasing stacking times, the optical properties of $Si_3N_4$/SnZnO/AZO/Ag/Ti/ITO multi-layer film get worse. Consequently, Ti layer is good for oxidation barrier, but too many uses of this layer may have an adverse effect to optical properties of TCO film.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.71-74
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• 2000

Pt/Pb$TiO_3$/$SrTiO_3$/p-Si films were prepared by metallo-organic solution deposition(M0SD) method and investigated its structure and ferroelectric properties. Crystallinity of specimen as a funtions of post annealing temperature and the thickness of $SrTiO_3$(STO) buffer layer was studied using XRD and AFM. Based on C-V and P-E curve, $PbTiO_3$(PTO) capacitors showed good ferroelectric hysteresis arising from the polarization switching properties. When the thickness of ST0 buffer layer between PTO and Si substrate was 260 nrn and the post annealing temperature was $650^{\circ}C$, it was showed that production of the pyrochlore phase due to interdiffusion of Si into FTO was prevented. The dielectric constant of FTO thin films calculated from a maximum Cma in the accumulation region was 180 and the dielectric loss was 0.30 at 100 kHz frequency. The memory window in the C-V curve is 1.6V at a gate voltage of 5V.

• Proceedings of the KIEE Conference
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• 2004.11a
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• pp.183-186
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• 2004

The metal-ferroelectric-insulator-semiconductor(MFIS) capacitors were fabricated using a metalorganic decomposition (MOD)method. The $CeO_2$ thin films were deposited as a buffer layer on Si substrate and $Bi_{3.25}La_{0.75}Ti_3O_{12}$ (BLT) thin films were used as a ferroelectric layer. The electrical and structural properties of the MFIS structure were investigated by varying the $CeO_2$ layer thickness. The width of the memory window in the capacitance-voltage (C-V)curves for the MFIS structure decreased with increasing thickness of the $CeO_2$ layer. Auger electron spectroscopy (AES) and transmission electron microscopy (TEM) show no interdiffusion by using the $CeO_2$ film as buffer layer between the BLT film and Si substrate. The experimental results show that the BLT-based MFIS structure is suitable for non-volatile memory field-effect-transistors (FETs) with large memory window.

• KIEE International Transactions on Electrophysics and Applications
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• v.12C no.4
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• pp.208-213
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• 2002

The present study describe the electrical performance of amorphous T $a_2$ $O_{5-X}$ fabricated on the buffer layers Ti and Ti $O_2$. T $a_2$ $O_{5-X}$ thin films were grown on the Ti and Ti $O_2$ layers as a capacitor layer using reactive sputtering method. The X-ray pattern analysis indicated that the two as-deposited films were amorphous and the amorphous state was kept stable on the RTA(rapid thermal annealing) at even $700^{\circ}C$. Measurements of dielectric properties of the reactive sputtered T $a_2$ $O_{5-X}$ thin films fabricated in two simple MIS(metal insulator semiconductor), structures, (Cu/T $a_2$ $O_{5}$ Ti/Si and CuT $a_2$ $O_{5}$ Ti $O_2$Si) show that the amorphous T $a_2$ $O_{5}$ grown on Ti showed high dielectric constant (23～39) and high leakage current density(10$^{-3}$ ～10$^{-4}$ (A/$\textrm{cm}^2$)), whereas relatively low dielectric constant (～15) and tow leakage current density(10$^{-9}$ ～10$^{-10}$ (A/$\textrm{cm}^2$)) were observed in the amorphous T $a_2$ $O_{5}$ deposited on the Ti $O_2$ layer. The electrical behaviors of the T $a_2$ $O^{5}$ thin films were attributed to the contribution of Ti- $O_2$ and the compositionally gradient Ta-Ti-0, being the low dielectric layer and high leakage current barrier. In additional, The T $a_2$ $O_{5}$ Ti $O_2$ thin films exhibited dominant conduction mechanism contributed by the Poole-Frenkel emission at high electric field. In the case of T $a_2$ $O_{5}$ Ti $O_2$ thin films were related to the diffusion of Ta, Ti and O, followed by the creation of vacancies, in the rapid thermal treated thin films.films.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.200-201
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• 2007

The SBT($SrBi_2Ta_2O_9$) thin films with $Bi_2O_3$ buffer layer were deposited on Pt/Ti/$SiO_2$/Si substrate by R.F. magnetron sputtering method in order to improve the ferroelectric characteristics. In SBT thin films, the deficiency of bismuth during the process due to its volatility results in an obvious non stoichiometry of the films and the presence of secondary phases. $Bi_2O_3$ buffer layer was found to be effective to achieve the low temperature crystallization and improve the ferroelectric properties of SBT thin films. Ferroelectric properties and crystallinities of SBT thin films with various post annealing of $Bi_2O_3$ buffer layer were observed as various annealing temperature, using X-Ray Diffraction (XRD), scanning electron microscopy (SEM), Keithley 237 and HP 4192A Impedance Analyzer.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.160-160
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• 2010

Organic electronic devices require a passivation layer to ensure sufficient lifetime. Specifically, flexible organic electronic devices need a barrier layer that transmits less than $10^{-6}\;g/m^2/day$ of water and $10^{-5}\;g/m^2/day$ of oxygen. To increase the lifetime of organic electronic device, therefore, it is indispensable to protect the organic materials from water and oxygen. Severe groups have reported on multi-layerd barriers consisting inorganic thin films deposited by plasma enhenced chemical deposition (PECVD) or sputtering. However, it is difficult to control the formation of granular-type morphology and microscopic pinholes in PECVD and sputtering. On the contrary, atomic layer deoposition (ALD) is free of pinhole, highly uniform, conformal films and show good step coverage. In this study, the passivation layer was deposited using single-process PEALD. The passivation layer, in our case, was a bilayer system consisting of $Al_2O_3$ films and a $TiO_2$ buffer layer on a poly (ether sulfon) (PES) substrate. Because the deposition temperature and plasma power have a significant effect on the properties of the passivation layer, the characteristics of the $Al_2O_3$ films were investigated in terms of density under different deposition temperatures and plasma powers. The effect of the $TiO_2$ buffer layer also was also addressed. In addition, the water vapor transmission rate (WVTR) and organic light-emitting diode (OLEDs) lifetime were measured after forming a bilayer composed of $Al_2O_3/TiO_2$ on a PES substrate.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.9
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• pp.807-811
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• 2003

We investigated the electrical characterisitics of T $a_2$ $O_{5}$ (tantalum pentoxide) film and Ti-O/T $a_2$ $O_{5}$ film deposited on $Al_2$ $O_3$based substrate. Ta (tantalum) electrode and $Al_2$ $O_3$ substrate was used for the purpose of simplifying the manufacturing process in IPD's (integrated passive devices). Dielectric materials (T $a_2$ $O_{5}$ and Ti-O/T $a_2$ $O_{5}$ films) deposited on Ta/Ti/A $l_2$ $O_3$ were annealed at 700 $^{\circ}C$ for 60 sec. in vacuum. The XRD results showed that as-deposited T $a_2$ $O_{5}$ film possessed amorphous structure, which was transformed to crystallines by rapid thermal heat treatment. We compared the lnJ- $E^{{\frac}{1}{2}}$, C-V, C-F of both as-deposited and annealed dielectric thin films deposited on Ta bottom electrode. From this results, we concluded that the leakage current could be reduced by introducing Ti-O buffer layer and conduction mechanisms of T $a_2$ $O_{5}$ and Ti-O/T $a_2$ $O_{5}$ could be interpreted appropriately by Schottky emission effect.