• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.217-221
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• 1997

We have investigated the ferroelectric properties of multi-layered SrBi$_2$Ta$_2$$O_{9}$Pb(Zr,Ti)O$_3$, SBT/PZT, thin film capacitors. Specimens were prepared onto Pt-coated Si wafer by sol-gel method. Ferroelectric properties of these finns could be obtained only for thin SBT layers below 50nm in thickness. The values of dielectric constant and remnant polarization depend mainly on the thickness of SBT layer, which arises from the paraelectric interface layer between SBT and PZT due to the thermal diffusion of Pb. The value of remnant poarization of PZT/SBT is greater than that of SBT, and the plarization fatigue behaviors of PZT/SBT/Pt capacitors are somewhat improved as compared with those of PZT/Pt.t.

• JSTS:Journal of Semiconductor Technology and Science
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• v.12 no.4
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• pp.449-457
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• 2012

The program/erase (P/E) cyclic endurances including bias temperature instability (BTI) behaviors of Metal-$Al_2O_3$-Nitride-Oxide-Semiconductor (MANOS) memories are investigated in comparison with those of Semiconductor-Oxide-Nitride-Oxide-Semiconductor (SONOS) memories. In terms of BTI behaviors, the SONOS power-law exponent n is ~0.3 independent of the P/E cycle and the temperature in the case of programmed cell, and 0.36~0.66 sensitive to the temperature in case of erased cell. Physical mechanisms are observed with thermally activated $h^*$ diffusion-induced Si/$SiO_2$ interface trap ($N_{IT}$) curing and Poole-Frenkel emission of holes trapped in border trap in the bottom oxide ($N_{OT}$). In terms of the BTI behavior in MANOS memory cells, the power-law exponent is n=0.4~0.9 in the programmed cell and n=0.65~1.2 in the erased cell, which means that the power law is strong function of the number of P/E cycles, not of the temperature. Related mechanism is can be explained by the competition between the cycle-induced degradation of P/E efficiency and the temperature-controlled $h^*$ diffusion followed by $N_{IT}$ passivation.

• Journal of the Korea Institute of Military Science and Technology
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• v.4 no.2
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• pp.122-129
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• 2001

A characterization procedure for analyzing symmetric coupled MIS(Metal-Insulator-Semiconductor) transmission line is used the same procedure as a general single layer symmetric coupled line with perfect dielectric substrate from the extraction of the characteristic impedance and propagation constant for even- and odd-mode. In this paper, an analysis for a new substrate shielding symmetric coupled MIS structure consisting of grounded crossbar at the interface between Si and SiO2 layer using the Finite- Difference Time-Domain(FDTD) method is presented. In order to reduce the substrate effects on the transmission line characteristics, a shielding structure consisting of grounded crossbar lines over time-domain signal has been examined. Symmetric coupled MIS transmission line parameters for even- and odd-mode are investigated as the functions of frequency, and the extracted distributed frequency- dependent transmission line parameters and corresponding equivalent circuit parameters as well as quality factor for the new MIS crossbar embedded structure are also presented. It is shown that the quality factor of the symmetric coupled transmission line can be improved without significant change in the characteristic impedance and effective dielectric constant.

• Korean Journal of Materials Research
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• v.15 no.2
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• pp.139-142
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• 2005

[ $ZrO_2$ ] gate dielectric thin films were deposited by radio frequency (rf)-magnetron sputtering and its structure, surface morphology and electrical peoperties were studied. As the oxygen flow rate increases, the surface becomes smoother. The experimental results indicate that a high temperature annealing is desirable since it improves the electrical properties of the $ZrO_2$ gate dielectric thin films by decreasing the number of interfacial traps at the $ZrO_2/Si$ interface. The carrier transport mechanism is dominated by the thermionic emission.

• Journal of the Korean Ceramic Society
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• v.51 no.4
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• pp.312-316
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• 2014

The joining behavior of forsterite ceramics to SUS304 alloy using $8PbO-78Bi_2O_3-8B_2O_3-4ZnO-2SiO_2$ (wt%) system glass frit was investigated. The contact angle was smaller than $90^{\circ}$ at a temperature of $460^{\circ}C$. Redox reaction at the interface between forsterite and SUS304 was found to appear when the electrons in the metal part moved toward the glass part and the oxygen ions in glass moved to the metal side. The decrease of the surface tension due to the PbO solubility on the forsterite side contributed to the better wetting behavior at low temperature.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1992.11a
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• pp.123-127
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• 1992

When MOS devices is exposed to radiation, radiation effects of P-type MOS capacitor can cause modulation and/or degradation in devices characteristics and its operating life. The oxide layer is grown in $O_2$+T.C.E. and its thickness ranges from 40 to 80 nm. Irradiations on MOS capacitor were performed by Cobalt-60 gamma ray source and total dose ranges from $10^4$ to $10^8$ rads. The radiation effect on electrical conduction characteristics(I-V) in MOS capacitor was measured as a function of gate oxide thickness and total dose. From the experimental result, I-V characteristics is found to be influenced strongly by total dose in irradiated p-type MOS capacitors. The ohmic current is dependant on of total dose in irradiated P-type MOS capacitors. This results are explained using surface states at interface radiation-induced traps.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.2 no.2
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• pp.40-52
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• 1992

$PbTi0_3$ thin films were deposited at $550^{\circ}C$ by MOCVD method using titanium-iso-propoxide [$Ti(OC_3H_7)_4$] and tetra-ethyl-lead $[Pb(C_2H_5)_4]$as starting materials. In the present study, Ar and $O_2$were used as a carrier gas and a reaction gas, respectively, and the change of thickness and refractive index, Xray diffraction analysis, and CV characteristic measurements of the films were systematically investigated. As a result of CV characteristic analysis of the annealed $PbTiO_3$ thin films, it is assumed that the films interact with Si substrate at the interface, and X-ray diffraction patterns of the films show characteristic peaks for $PbTiO_3$ With increasing the annealing temperature and time, the thickness of the films tends to decrease but their refractive index increases.

• Transactions on Electrical and Electronic Materials
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• v.8 no.2
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• pp.84-88
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• 2007

[ $Bi_{1.5}Zn_{1.0}Nb_{1.5}O_7$ ] (BZN), $Bi_2Mg_{2/3}Nb_{4/3}O_7$ (BMN), and $Bi_2Cu_{2/3}Nb_{4/3}O_7$ (BCN) pyrochlore thin films were prepared on $Cu/Ti/SiO_2/Si$ substrates by pulsed laser deposition and the micro-structural and electrical properties were characterized for embedded capacitor applications. The BZN, BMN, and BCN films deposited at $25\;^{\circ}C$ and $150\;^{\circ}C$, respectively show smooth surface morphologies and dielectric constants of about $39\;{\sim}\;58$. The high dielectric loss of the films deposited at $150\;^{\circ}C$ compared with films deposited at $25\;^{\circ}C$ was attributed to the defects existing at interface between the films and copper electrode by an oxidation of copper bottom electrode. The leakage current densities and breakdown voltages in 200 nm thick-BMN and BZN films deposited at $150\;^{\circ}C$ are approximately $2.5\;{\times}\;10^{-8}\;A/cm^2$ at 3 V and above 10 V, respectively. Both BZN and BMN films are considered to be suitable materials for embedded capacitor applications.

• Journal of the Korean Ceramic Society
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• v.51 no.5
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• pp.511-515
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• 2014

The thermodynamic instability of bubbles in wet-foam colloidal suspension is due to the substantial area of their gas/liquid interface. Several physical processes lead to gas diffusion from smaller to larger bubbles, resulting in a coarsening and Ostwald ripening of wet foam. This includes a narrowing of the bubble size distribution. The distribution and microstructure of porous ceramics, the adsorption free energy and Laplace pressure of $Al_2O_3$ particle-stabilized colloidal suspension, and $SiO_2$ content were investigated for tailoring the bubble size. Wet-foam stability of more than 80% is related to the degree of hydrophobicity with contact angles of $62-70^{\circ}$ achieved from the surfactant. The contact angle replaces part of the highly energetic interface and lowers the free energy of the system. This leads to an apparent increase in the surface tension (26-33 mN/m) of the colloidal suspension.

• Korean Journal of Materials Research
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• v.8 no.7
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• pp.621-627
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• 1998

The formation of Co-silicide between Co/Zr bilayer on the amorphous and crystalline Si substrates has been investigated. The films of Zr(50$\AA$) and Co(l50$\AA$) were deposited with e-beam evaporation system and were heattreated with the rapid thermal annealing system at the temperatures between 50$0^{\circ}C$ and 80$0^{\circ}C$ with 10$0^{\circ}C$ increments for 30 seconds. The phase identification of Co-silicide was carried out by XRD and the chemical analysis was examined by AES and RBS. The interface morphologies of Co/Zr bilayer films were investigated by cross sectional TEM and HRTEM. $CoSi_2$ was formed epitaxially on the crystalline Si substrate above $700^{\circ}C$ while polycrystalline $CoSi_2$ was grown on the amorphous Si substrate. The formation temperature of Co-silicide on the amorphous Si substrate was about 100 C lower than that on the crystalline Si. The COzSi phase was not identified on the both Si substrates. The formation temperature of first phase of Co-silicide on ColZr bilayer was higher than that on Co mono layer. CoSizlayer formed on the amorphous Si substrate exhibits better uniformity compared to the CoSiz formed on the crystalline substrate. The sheet resistance of CoSiz layer on crystalline Si was lower than that on the amorphous Si at high temperatures.tures.