• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.11
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• pp.35-43
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• 1995

To obtain high quality of $Ta_{2}O_{5}$ film, two dielectric layers of $Si_{3}N_{4}$ and $Ta_{2}O_{5}$ were subsequently formed on Si wafer. Silicon nitride films were thermally grown in 10 Torr ammonia ambient by R.F induced heating system. The thickness of thermally grown $Si_{3}N_{4}$ film was able to be controlled in the range of tens $\AA$ due to the self-limited growth property. $Ta_{2}O_{5}$ film of 200$\AA$ thickness was then deposited on the as-grown $Si_{3}N_{4}$ film about 25$\AA$ thickness by sputtering method and annealed at $900^{\circ}C$in $O_{2}$ ambient for 1hr. Stoichiometry film was prepared by the annealing in oxygen ambient. Despite the high temperature anneal process, silicon oxide layer was not grown at the interface of the layered films because of the oxidation barrier effect of Si$_{3}$N$_{4}$ film. The fabricated $Ta_{2}O_{5}$/$Si_{3}N_{4}$ film showed low leakage current less than several nA and high dielectric breakdown strength.

• Journal of the Microelectronics and Packaging Society
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• v.12 no.3 s.36
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• pp.235-241
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• 2005

Incorporation of solid electrodes frequently involves plasma-based processing. The effect of plasma can influence the physical characteristics, depending on the magnitude in plasma. The undesired feature of plasma-induced damage should be prevented in characterizing the ultra-thin materials, such as ultra-thin films and organic monolayers. The current work at first proves the applicability of a liquid phase electrode in the electrical/dielectric properties through comparative work using Al and Hg on ultrathin $Al_2O_3$ films deposited through atomic layer deposition at low temperature: Two types of metals such as Aluminum (Al) and mercury (Hg) were used as electrodes in $Al_2O_3$ thin films in order to investigate the effect of electrode preparation on the current-voltage characteristics and impedance features as a function of thickness in $Al_2O_3$ film thickness. The success of Hg in $Al_2O_3$ thin films is applied to the AC and DC characterization of the organic monolayers obtained using the Langmuir-Blodgett method. From the DC current-voltage characteristics, the diode-like response is found to originate from the bulk response of the organic materials, evidenced by the fact and the capacitance is inversely related to the absolute thickness of organic layers.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.5
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• pp.351-355
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• 2001

Via for achieving reliable fabrication of MCM(Multichip Module) substrate was formed on photosensitive BCB layer. The MCM substrate consists of photosensitive BCB(Benzocyclobutene) interlayer dielectric and copper conductors. In order to form the vias in the photosensitive BCB layer, the process of forming the BCB layer and its via forming plasma etch using C$_2$F$\_$6//O$_2$ gas were evaluated. The thickness of the BCB layer after hard bake was shrunk down to 40% of the original. The resolution of vias formed on the BCB was 15㎛ and the slope after develop was 85 degree. AES analysis was done on two vias, one is etched in C$_2$F$\_$6/O$_2$ gas and the other isnot etched. On the via etched in C$_2$F$\_$6//O$_2$, native C was detected and the amount of native C was reduced after Ar sputter. On the via not etched in C$_2$F$\_$6//O$_2$, organic C was detected. As a result of AES, BCB residue was not removed by Ar sputter, so plasma etch is necessary for achieving reliable vias.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1546-1548
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• 2002

In this paper, the electrical characteristics of pentacene thin film transistors(TFTs) with stacked and surface-treated gate insulators have been investigated. The semiconductor layer of pentacene was thermally evaporated onto the stacked gate insulators. For the gate insulating materials. PVP(PolyvinylPhenol) and polystyrene were spin-coated with two different stacking orders, PVP-polystyrene and polystyrene-PVP. Rapid solvent evaporation during the spin-coating processes of these insulating layers produces non-equilibrium phase morphologies accompanied by surface undulations on gate insulator interfaces. This non-equilibrium phase morphology affects the growth mode of the subsequent pentacene layer. Therefore, in order to smoothen the gate dielectric surfaces, gate dielectric surfaces were rubbed laterally along the direction from the drain to the source TFTs with with stacked and surface-treated gate insulators have provided improved operational characteristics.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.12S
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• pp.1175-1180
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• 2003

Transformer Coupled Plasma Chemical Vapor Deposited (TCP-CVD) silicon nitride (SiNx) is widely used as a gate dielectric material for thin film transistors (TFT). This paper reports the SiNx films, grown by TCP-CVD at the low temperature (30$0^{\circ}C$). Experimental investigations were carried out for the optimization o(SiNx film as a function of $N_2$/SiH$_4$ flow ratio varying ,3 to 50 keeping rf power of 200 W, This paper presents the dielectric studies of SiNx gate in terms of deposition rate, hydrogen content, etch rate and leakage current density characteristics lot the thin film transistor applications. And also, this work investigated means to decrease the leakage current of SiNx film by employing $N_2$ plasma treatment. The insulator layers were prepared by two step process; the $N_2$ plasma treatment and then PECVD SiNx deposition with SiH$_4$, $N_2$gases.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.286-286
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• 2016

Hexagonal boron nitride (hBN) is a dielectric insulator with a two-dimensional (2D) layered structure. It is an appealing substrate dielectric for many applications due to its favorable properties, such as a wide band gap energy, chemical inertness and high thermal conductivity[1]. Furthermore, its remarkable mechanical strength renders few-layered hBN a flexible and transparent substrate, ideal for next-generation electronics and optoelectronics in applications. However, the difficulty of preparing high quality large-area hBN films has hindered their widespread use. Generally, large-area hBN layers prepared by chemical vapor deposition (CVD) usually exhibit polycrystalline structures with a typical average grain size of several microns. It has been reported that grain boundaries or dislocations in hBN can degrade its electronic or mechanical properties. Accordingly, large-area single crystalline hBN layers are desired to fully realize the potential advantages of hBN in device applications. In this presentation, we report the growth and transfer of centimeter-sized, nearly single crystal hexagonal boron nitride (hBN) few-layer films using Ni(111) single crystal substrates. The hBN films were grown on Ni(111) substrates using atmospheric pressure chemical vapor deposition (APCVD). The grown films were transferred to arbitrary substrates via an electrochemical delamination technique, and remaining Ni(111) substrates were repeatedly re-used. The crystallinity of the grown films from the atomic to centimeter scale was confirmed based on transmission electron microscopy (TEM) and reflection high energy electron diffraction (RHEED). Careful study of the growth parameters was also carried out. Moreover, various characterizations confirmed that the grown films exhibited typical characteristics of hexagonal boron nitride layers over the entire area. Our results suggest that hBN can be widely used in various applications where large-area, high quality, and single crystalline 2D insulating layers are required.

• The Journal of Engineering Geology
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• v.14 no.3 s.40
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• pp.301-311
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• 2004

This study is suggested a new dielectric tracer test method to understand geological structure of porous media and groundwater flow to use the dielectric constant which is one of electrical special quality of various geological materials. To measure their parameters, tracer material is made an ethanol mixing liquid(EML) having a same specific gravity of water. Also, soil materials are prepared a dielectric tracer test using the FDR system that could measure dielectric constant for saturated standard sand and river sand layers which have different initial porosity. To compare with their results, we discussed with the concentration variation of saline water having a saline concentration $3\%$ which is general tracer material by using the electro multi-meter system in the laboratory or field test. In two tracer experiment results, EML tracer test could confirm definitely EML concentration variation from each saturated soil layer as standard and river sands. However, tracer test of saline water $3\%$ concentration could not confirm permeating movement of water by degree of salinity change because these are settled at lower part column in a whole column area continuously. These causes are that specific gravity of saline water is heavier than water. That is, it could know that deposition of saline water is composed of lower part of soil column continuously independently of the direction of water into saturated soil material.

• Journal of Electrical Engineering and Technology
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• v.4 no.2
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• pp.282-286
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• 2009

This paper presents the design of a patch antenna for GPS portable devices. The antenna is designed to operate at Ll band on an FR4 PCB with a thickness of 1.6mm, a dielectric constant of 3.8 and two metallization layers. The antenna has a dimension of 49mm${\times}$36mm and operates at 1.5754GHz with a return loss of -36dB and a measured bandwidth of 250MHz.

• Proceedings of the KIEE Conference
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• 2006.10a
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• pp.158-159
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• 2006

The resistance-capacitance (RC) delay of signals through interconnection materials becomes a big hurdle for high speed operation of semiconductors which contain multilayer interconnection layers. In order to reduce the RC delay, low-k materials will be used for inter-metal dielectric (IMD) materials. We have developed self-consistent simulation tool that includes neutral-species transport model, based on the relaxation continuum (RCT) model. We present the parametric study of the modeling results of a two-frequency capacitively coupled plasma (2f-CCP) with $N_2/H_2$ gas mixture that is known as promising one for organic low-k materials etching. We include the neutral transport model as well as plasma one in the calculation. The plasma and neutrals are calculated self-consistently by iterating the simulation of both species till a spatiotemporal steady state profile could be obtained.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.4 no.1
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• pp.31-36
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• 2005

In this paper, a planar type bandpass filter in multilayered PCB is presented. The multilayered PCB structure has some advantages on fabricating microwave devices such as the size reduction and ability of tight coupling by folding or embedding. The proposed BPF has two transmission zeros at the both sides of the center frequency by using independent electric and magnetic coupling structure. The designed BPF with four layer teflon PCBs of dielectric constant 2.94 has dimensions of 24x20x1.524 in mm, center frequency of 2.47GHz and bandwidth of about l00MHz. A good agrement is achieved between the measured result and the simulated one. The influences of air gaps between the layers are also analyzed and presented.