• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1998.11a
• /
• pp.243-246
• /
• 1998

(Ba, Sr)TiO$_3$[BST] thin films were fabricated on Pt/SiO$_2$/Si substrate by RF sputtering technique. The structural, dielectric and electrical properties of BST thin films were investigated with Ar/O$_2$ ratio. Dielectric constant and dielectric loss of the BST thin film were about 1020 and 2.0[%], respectively. (at RF power 80W, post annealing temperature $650^{\circ}C$, deposition pressure of 5mTorr and Ar/O$_2$=80/20). For the BST(Ar/O$_2$=80/20) thin film with Polarization switching cycles of 10$^{10}$ , remanent polarization and coercive field were 0.084[$\mu$C/cm$^2$], 1.954[kV/cm], respectively.

• Proceedings of the KIEE Conference
• /
• 1994.07b
• /
• pp.1466-1468
• /
• 1994

In this paper Dielectric and strain properties of (1-x-y)PMN-yPT-xST Ceramics have been investigated as a function of the amount of $SrTiO_3(ST)$. The $SrTiO_3$ content is ranged from 0.01-0.06(wt%). As the amount of ST is increased, dielectric constant has a maximum value at 0.05 mol composition. The Curie temperature is decreased linearly with increasing ST composition and Polarization properties have been investigated. Coercive field and ramnant polarization has a maximum value at 0.01mol composition.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1999.05a
• /
• pp.113-117
• /
• 1999

SrBi$_2$Ta$_2$$O_{9}$ (SBT) thin films were fabricatcd with different Sr/Bi ratios by MOD. SBT thin films of thickness 2500$\AA$ deposited on Pt/Ti/SiO$_2$/Si were crystallized at $700^{\circ}C$ ~85$0^{\circ}C$ using RTA method. As the Sr/Bi ratio was decreased, dielectric constant and remanent polarization were increased. SrBi$_2$Ta$_2$$O_{9}$ showed a maximum dielectric constant value of $\varepsilon$$_{r}$= 268, and maximum remanent polarization (2Pr) of ~9.86 $\mu$C/$\textrm{cm}^2$ when annealed at 8$0^{\circ}C$ for 8 min.min.n.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1994.05a
• /
• pp.5-8
• /
• 1994

In this paper, Dielectric and strain properties of (1-x-y)PMN-yPT-xST Ceramics hale been investigated as a function of the amount of SrTiO$_3$(ST). The SrTiO$_3$ content is ranged from 0.01-0.05(wt%). As the amount of ST is increased, dielectric constant has a maximun value at 0.05 mol% composition. The Curie temperature is decreased linearly with increasing ST composition and Polarization properties have been investigated. Coercive field and remnant polarization has a maximum value at 0.01mo1% composiion.

• Transactions on Electrical and Electronic Materials
• /
• v.3 no.1
• /
• pp.42-45
• /
• 2002

Properties of lead zirconate titanate ferroelectric thin films prepared by rapid thermal annealing/direct insertion thermal annealing were investigated. The remnant polarization (Pr), saturation polarization (Ps), and coercive force (Ec) of typical samples annealed by rapid thermal annealing (RTA) are about 13.7 $\mu$ C/cm$^2$, 27.1 $\mu$C/cm$^2$, and 55.6 kV/cm, respectively. The dielectric constant of the sample is about 786, the dielectric loss tangent is about 2.4% at 1 kHz. Furthermore, ferroelectric, conduction, and piezoelectric properties of the thin films annealed by RTA process and the direct insertion thermal annealing (DITA) process were compared. The influence of temperature in the dry process on the above properties was also investigated.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2003.09a
• /
• pp.289-292
• /
• 2003

Laboratory tests were performed to investigate the dielectric property of saturated sands contaminated by heavy metals solution at low frequency. Differences of contamination and the real part of dielectric constant depend on heavy metal concentration was measured at low frequency, 100KHz below. The optimal frequency to develop the detection potentials of monitoring was 1KHz, 10KHz, 100KHz. At this frequency, Heavy metal contamination of saturated sands contamination can be recommended by analysis of complex dielectric constant.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.13 no.4
• /
• pp.300-305
• /
• 2000

We have investigated the dielectric and electrical characteristics of palmitic acid(PA) stearic acid(SA) and arachidic acid(AA) Langmuir-Blodgett(LB) films because these fatty acid systems have a same hydrophilic group and a different hydrophobic one(methylene group or alkyl chain length). The fatty acid systems were used as LB films and the status of the deposited films was confirmed by evaluating the transfer ratio the UV absorption and the capacitance. The dielectric characteristics such as the frequency-capacitance characteristics and the dielectric dispersion and absorption characteristics of PA SA and AA through-plane were measured. The relative dielectric constants of PA, SA and AA LB films were about 3.0~4.6, 2.7~3.0 and 2.4~3.0 respectively. That is the relative dielectric constants were decreased in proportion to the chain length of methylene group. Also the dielectric dispersion and absorption of each fatty acid LB films have arisen from spontaneous polarization of dipole polarization in the range of 10$^4$~10$^{5}$ ［Hz］. The conductivity of PA, SA and AA LB films obtained from I-V characteristics were about 9$\times$10$^{-14}$ , 3$\times$10$^{-14}$ and 5$\times$10$^{-15}$ ［S/cm］. respectively. These results have shown the insulating materials and could control the conductivity y changing the length of methylene group. Also we have confirmed that the barrier height of fatty acid systems were almost the same ones obtained from dielectric characteristics.

• Journal of the Korean Ceramic Society
• /
• v.36 no.9
• /
• pp.923-929
• /
• 1999

The cause of optical nonlinearity induced in thermally poled silica glass is believed to be the space charge polarization. Since the second order optical nonlinearity (electro-optic effect) can be used in optical switches the optical nonlinearity in silica glass has drawn a large attention. Space charge polarization occurs when an ionic conducting material is subjected to dc electric field by the blocking electrode. Thermal poling performed to induce the optical nonlinearity in silica glass is basically identical to the process generating space charge polarization. As a first step to understand the mechanism of space charge polarization in silica glass hence the induced optical nonlinearity the absorption currents as functions of time were measured for various types of silica glasses and analyzed by the theory of space charge polarization. It was found that the electrical relaxation exhibited a step by the space charge polarization in the relatively long time range and dielectric loss peak showed a maximum at a specific temperature which is depending on type of silica glass. It was turned out that this relaxation might be a cause of nonlinearity in electrical conductivity of silica glass.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.11 no.12
• /
• pp.1108-1114
• /
• 1998

$BaTiO_3$ thin films preferred c-axis orientation for the potential application of ferroelectric memory devices were deposited on silicon substrates(100) by RF sputtering and annealed at 800 and 900[$^{\circ}C$] in air. The BT(100)/BT(110) peak ratio of the sputtered sample was decreased with post-annealing in air. According to increasing with annealing temperature and time, the peak ratio of BT(100)/BT(110) was decreased and the surface density of thin film was high. Dielectric characteristics of $BaTiO_3$ thin film was measured as a function of annealing temperature and frequency. The dielectric constants were increased with annealing and decreased with frequency by space charge polarization and dipole polarization below 600[kHz]. The remanent polarization and coercive field in P-E hysteresis loop of $BaTiO_3$thin film were increased with the annealing temperature in air. The remanent polarization and coercive filed annealed at 800[$^{\circ}C$] for 1hr were 1.2[$\mu$C/$cm^2$] and 200[kV/cm]

• Proceedings of the IEEK Conference
• /
• 1998.10a
• /
• pp.371-374
• /
• 1998

The Scattering of arbitrarily shaped gratings covered with dielectric slab is considered. The total field in each region is expressed in terms of incident field and scattered field by induced currents on the surface of the grating. Some numerical results is presented nd compared with previous ones in cases of several gratings.