• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.168-168
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• 2008

Dimension of a transistor has rapidly shrunk to increase the speed of device and to reduce the power consumption. However, it is accompanied with several problems like direct tunneling through the gate dioxide layer and low conductivity characteristic of poly-Si gate in nano-region. To cover these faults, study of new materials is urgently needed. Recently, high dielectric materials like $Al_2O_3$, $ZrO_2$, and $HfO_2$ are being studied for equivalent oxide thickness (EOT). However, poly-Si gate is not compatible with high-k materials for gate-insulator. Poly Si gate with high-k material has some problems such as gate depletion and dopant penetration problems. Therefore, new gate structure or materials that are compatible with high-k materials are also needed. TiN for metal/high-k gate stack is conductive enough to allow a good electrical connection and compatible with high-k materials. According to this trend, the study on dry etching of TiN for metal/high-k gate stack is needed. In this study, the investigations of the TiN etching characteristics were carried out using the inductively coupled $BCl_3$-based plasma system and adding $Cl_2$ gas. Dry etching of the TiN was studied by varying the etching parameters including $BCl_3$/Ar gas mixing ratio, RF power, DC-bias voltage to substrate, and $Cl_2$ gas addition. The plasmas were characterized by optical emission spectroscopy analysis. Scanning electron microscopy was used to investigate the etching profile.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.27-27
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• 2008

The different concentration Indium doped ZnO:Al films were grown on glass substrates (Corning 1737) at $200^{\circ}C$ by pulsed laser deposition. The indium doping in AZO films shows the critical effect on the crystallinity, resistivity, and optical properties of the films. The AZO films doped with 0.3 atom % indium content exhibit the highest crystallinity, the lowest resistivity of $4.5\times10^{-4}\Omega$-cm, and the maximum transmittance of 93%. The resistivity of the indium doped-AZO films is strongly related with the crystallinity of the films. The carrier concentration in the indium doped-AZO films linearly increases with increasing indium concentration. The mobility of the AZO films with increasing indium concentration was reduced with an increase in carrier concentration and the decrease in mobility was attributed to the ionized impurity scattering mechanism. In an optical transmittance, the shift of the optical absorption edge to shorter wavelength strongly depends on the electronic carrier concentration in the films.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.1A
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• pp.80-86
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• 2010

This work has been measured and analyzed the device degradation of NBTI (Negative Bias Temperature Instability) stress induced the increase of gate-induced-drain-leakage(GIDL) current for p-MOS transistors of gate channel length 0.13 [${\mu}m$]. From the relation between the variation of threshold voltage and subthreshold slop by NBTI stress, it has been found that the dominant mechanism for device degradation is the interface state generation. From the GIDL measurement results, we confined that the EHP generation in interface state due to NBTI stress led to the increase of GIDL current. As a results, one should take care of the increased GIDL current after NBTI stress in the ultra-thin gate oxide device. Also, the simultaneous consideration of reliability characteristics and dc device performance is highly necessary in the stress parameters of nanoscale CMOS communication circuit design.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.239-242
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• 1998

Ca $F_2$ films have superior gate insulator properties than conventional gate insulator such as $SiO_2$, Si $N_{x}$, $SiO_{x}$, and T $a_2$ $O_{5}$ to the side of lattice mismatch between Si substrate and interface trap charge density( $D_{it}$). Therefore, this material is enable to apply Thin Film Transistor(TFT) gate insulator. Most of gate oxide film have exhibited problems on high trap charge density, interface state in corporation with O-H bond created by mobile hydrogen and oxygen atom. This paper performed Ca $F_2$ property evaluation as MIM, MIS device fabrication. Ca $F_2$ films were deposited at the various substrate temperature using a thermal evaporation. Ca $F_2$ films was grown as polycrystalline film and showed grain size variation as a function of substrate temperature and RTA post-annealing treatment. C-V, I-V results exhibit almost low $D_{it}$(1.8$\times$10$^{11}$ $cm^{-1}$ /le $V^{-1}$ ) and higher $E_{br}$ (>0.87MV/cm) than reported that formerly. Structural analysis indicate that low $D_{it}$ and high $E_{br}$ were caused by low lattice mismatch(6%) and crystal growth direction. Ca $F_2$ as a gate insulator of TFT are presented in this paper paperaper

• Korean Chemical Engineering Research
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• v.46 no.1
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• pp.50-55
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• 2008

Carbon Nanotube (CNT) films were deposited with varying deposition temperature by RF plasma CVD on Fe catalysts deposited onto $SiO_2$ films grown thermally on the silicon wafer using $C_2H_2$ and $H_2$ gases. The Fe catalysts on silicon oxide film were made by RF magnetron sputtering. The grounded grid mesh cover on the substrate holder was used for depositing CNT thin films with high purity. The surface morphologies and chemical structure of deposited CNT films were characterized using SEM, Raman, XPS and TEM. It was observed that deposited CNTs films were carbon fiber type having Bamboo-like multiwall structure and CNT film grown at $600^{\circ}C$ was more dense than that at $550^{\circ}C$, but become less dense at $650^{\circ}C$.

• Corrosion Science and Technology
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• v.9 no.2
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• pp.81-86
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• 2010

The mechanisms of selective oxidation of intercritically annealed CMnAl TRIP steels in a Continuous Galvanizing Line (GCL) were studied by cross-sectional observation of the surface and sub-surface regions by means of High Resolution Transmission Electron Microscopy (HR-TEM). The selective oxidation and nitriding of an intercritically annealed CMnAl TRIP steel in a controlled dew point 10%$H_2+N_2$ atmosphere resulted in the formation of c-xMnO.$MnO_2$ (1${\leq}$x<3) and c-xMnO.$Al_2O_3$ ($x{\geq}1$) particles on the steel surface. Single crystal c-xMnO.$SiO_2$ ($2{\leq}x{\leq}4$) oxide particles were also observed on the surface. A thin film of crystalline c-xMnO.$SiO_2$ (2${\leq}$x<3) and c-xMnO.$Al_2O_3$ ($x{\geq}1$) was present between these particles. In the sub-surface region, internal oxidation, nitriding and intermetallic compound formation were observed. In the first region, large crystalline c-xMnO.$SiO_2$ ($1{\geq}x{\geq}2$) and c-xMnO.$Al_2O_3$ ($x{\geq}1$) oxides particles were present. In the second region, c-AlN particles were observed, and in a third region, small $MnAl_x$ (x>1) intermetallic compound particles were observed.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.4
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• pp.67-72
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• 1989

Room Temperature Plasma Nitridation of silicon was investigated as a new LOCOS (local oxidation of silicon) process in order to reduce the bird's beak length. In $N_2$ plasma formed by 100kHz, 400W AC power, a thin silicon nitride film (<100${\AA}$) was uniformly grown on a silicon substrate. SEM studies showed that the nitride layer formed by this method can effectively protect the silicon from oxidation and reduce the bird's beak length to $0.2{mu}m$ when 4000${\AA}$ field oxide is grown. This is a considerable improvement comparing with 0.7${mu}m,$ the bird's beak, for the conventional LOCOS process using a thick LPCVD nitride. No appreciable crystalline defect could be found around the bird's beak with SEM cross-section afrer Secco etch. Leakage current tests were carried out on the $N^+/P^-$ well and $P^+/N^-$ well diodes formed by this new LOCOS process. The electrical tests indicate that this new process has electrical properties similar or superior to those of the conventional LOCOS process.

• JSTS:Journal of Semiconductor Technology and Science
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• v.14 no.1
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• pp.53-60
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• 2014

Different kinds of post-deposition annealing (PDA) by a rapid thermal process (RTP) are used to enhance the field-effect passivation of $Al_2O_3$ film in crystal Si solar cells. To characterize the effects of PDA on $Al_2O_3$ and the interface, metal-insulator semiconductor (MIS) devices were fabricated. The effects of PDA were characterized as functions of RTP temperature from $400{\sim}700^{\circ}C$ and RTP time from 30~120 s. A high temperature PDA can retard the passivation of thin $Al_2O_3$ film in c-Si solar cells. PDA by RTP at $400^{\circ}C$ results in better passivation than a PDA at $400^{\circ}C$ in forming gas ($H_2$ 4% in $N_2$) for 30 minutes. A high thermal budget causes blistering on $Al_2O_3$ film, which degrades its thermal stability and effective lifetime. It is related to the film structure, deposition temperature, thickness of the film, and annealing temperature. RTP shows the possibility of being applied to the PDA of $Al_2O_3$ film. Optimal PDA conditions should be studied for specific $Al_2O_3$ films, considering blistering.

• Corrosion Science and Technology
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• v.19 no.4
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• pp.196-202
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• 2020

The air vent connected to a heat supply pipeline in the district heating system has been used to eliminate the existing air in the pipe, which has a detrimental effect on corrosion durability and heat efficiency. Recently, the air vent installed under a manhole for 22 years was corroded and several pinholes were detected in the front-end of the air vent. To identify the cause of the failure, thickness reduction, corrosion products, and water quality were examined. The corrosion damage was significant at the outside of the front-end of the air vent where the insulator was covered. While a thin oxide layer was formed in the interior of the tube, the coarse and porous corrosion products consisting of magnetite and hematite were found externally. Water flowing into the thermal insulator was absorbed by the insulator following hydrolysis. The hydrolyzed insulator ejected the corrosion factors such as Cl^-, SO₄^2-, and NH₄⁺. The findings suggest that the corrosion under insulation due to rain water is the main cause of the underlying failure in the air vent.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.111-114
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• 1999

Electroluminescence(EL) devices based on organic thin films have been attracted lots of interests in large-area light-emitting display. In this stuffy, an emissive layer was fabricated using Langmuir-Blodgett(LB) technique in organic light-emitting (OLEDs). This emissive organic material was synthesized and named PECCP[poly(3.6-N-2-ethylhexyl carbazolyl cyanoterephthalidene)] which has a strong electron donor group and an electron acceptor group in main chain repeated unit. This material has good solubility in common organic solvents such as chloroform. THF, etc, and has a good stability in air. The Langmuir-Blodgett(LB) technique has the advantage of precise control of the thickness down to the molecular scale, In particular, by varying the film thickness it is possible to investigate the metal/polymer interface. Optimum conditions for the LB film deposition are usually determined by investigating a relationship between a surface pressure $\pi$ and an effective are A occupied by one molecule on the subphase. The LB films were deposited on an indium-tin-oxide(ITO) glass at a surface pressure of 10 mN/m and dipping speed of 12 mm/min after spreading PECCP solution on distilled water surphase at room temperature, Cell structure was ITO/PECCP LB film/Alq$_3$/Al. We considered PECCP as a hole -transport layer inserted between the emissive layer and ITO. We also used Alq$_3$ as an emissive layer and an electron transport layer. We measured current-voltage(I-V) characteristics, UV/visible absorption, PL spectrum and EL spectrum of the OLEDs.