• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.3
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• pp.208-212
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• 2008

This paper reports physical properties of in situ boron doped silicon films made from boron source gas and silane ($SiH_4$) gas in a conventional low-pressure chemical vapor deposition vertical furnace. If the p-type polysilicon is formed by boron implantation into undoped polysilicon, the plasma nitridation (PN) process is added on the oxide in order to suppress boron penetration that can be caused during the thermal treatments used in fabrication. In-situ boron doped polysilicon deposition can complete p-type polysilicon film with only one deposition process and need not the PN process, because there is not interdiffusion of dopant at the intermediate temperatures of the subsequent steps. Since in-situ boron doped polysilicon films have higher work function than that of n-type polysilicon and they are compatible with the underlying oxide, they may be promising materials for improving memory cell characteristics if we make its profit of these physical properties.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1352-1353
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• 2008

In this study, aluminium - doped zinc oxide (ZnO:Al) transparent conducting film was deposited on PET(polyethylen terephthalate) substrate by r.f. magnetron sputtering method. PET substrate was surface-treated in an atmospheric pressure DBD(dielectric barrier discharge) plasma to increase deposition rate and to improve electrical propesties. Morphological changes by DBD plasma were obsered using contact angle measurement. The contact angle of water on PET was reduced from 62$^{\circ}$ to 42$^{\circ}$ by DBD plasma surface treatment. The plasma treatment also increased deposition rate and electrical propesties. The electrical resistivity as low as $4.97{\times}10^{-3}[{\Omega}-cm]$ and the deposition rate of 234[${\AA}$-m/min] were obtained in ZnO:Al film with surface treatment time of 5min, and 20min., respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05c
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• pp.41-46
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• 2002

In this work, we studied electrical characteristics and leakage current mechanism of Au/$Ta_2O_5$/Si metal-oxide-semiconductor (MOS) devices. $Ta_2O_5$ thin film (63nm) was deposited by atomic layer deposition (ALD) method at temperature of $235^{\circ}C$. The structures of the $Ta_2O_5$ thin films were examined by X-Ray Diffraction (XRD). From XRD, the structure of $Ta_2O_5$ was single phase and orthorhombic. From capacitance-voltage (C-V) analysis, the dielectric constant was 19.4. The temperature dependence of current-voltage (I-V) characteristics of $Ta_2O_5$ thin film was studied from 300 to 423 K. In ohmic region (<0.5 MVcm${-1}$), the resistivity was $2.4056{\times}10^{14}({\Omega}cm)$ at 348 K. The Schottky emission is dominant in lower temperature range from 300 to 323 K and Poole-Frenkel emission dominant in higher temperature range from 348 to 423 K.

• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.77.1-77.1
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• 2012

Zn 기반 산화물 반도체는 기존의 비정질 Si에 비해 저온공정에도 불구하고 높은 이동도, 투명하다는 장점으로 인해 차세대 디스플레이용 백플레인 소자로 주목받고 있다. 산화물 트랜지스터는 우수한 소자특성을 보여주고 있지만, 온도, 빛, 그리고 게이트 바이어스 스트레스에 의한 문턱전압의 불안정성이 문제의 문제를 해결해야한다. 산화물 반도체의 문턱전압의 불안정성은 유전체와 채널층의 계면 혹은 채널에서의 charge trap, photo-generated carrier, ads-/desorption of molecular 등의 원인으로 보고되고 있어, 고신뢰성의 산화물 채널층을 성장하기 위한 노력이 이루어지고 있다. 최근, 산화물 트랜지스터의 다양한 조건에서의 문턱전압의 불안정성을 해결하기 위해 산화물의 주된 결함으로 일컬어지고 있는 산소결핍을 억제하기 위해 성장공정의 제어 그리고, 산소와의 높은 binding energy를 같은 Al, Hf, Si 등과 같은 원소를 첨가하여 향상된 소자의 특성이 보고되고 있지만, 줄어든 산소공공으로 인해 이동도가 저하되는 문제점이 야기되고 있다. 이러한 문제점을 해결하기 위해, 최근에는 Buried layer의 삽입 혹은 bi-channel 등과 같은 방안들이 제안되고 있다. 본 연구는 atomic layer deposition을 이용하여 AZO bureid layer가 적용된 ZnO 트랜지스터의 특성과 안정성에 대한 연구를 하였다. 다결정 ZnO 채널은 유전체와의 계면에 많은 interface trap density로 인해 positive gate bias stress에 의한 문턱전압의 불안정성을 보였지만, AZO층이 적용된 ZnO 트랜지스터는 줄어든 interface trap density로 인해 향산된 stability를 보였다.

• Bulletin of the Korean Chemical Society
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• v.34 no.4
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• pp.1199-1204
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• 2013

Nanocomposites consisting of Sn nanoparticles and graphene oxide (GO) were electrophoretically deposited onto Cu current collectors that was used for anodes in Li ion batteries (LIBs). In order to optimize the electrochemical performance of nanocomposites as an anode material by controlling the oxygen functionality, the GO was subjected to $O_3$ treatment prior to electrophoretic deposition (EPD). During thermal reduction of the GO in the nanocomposites, the Sn nanoparticles were reduced in size, along with the formation of SnO and/or $SnO_2$ at a small fraction, relying on the oxygen functionalities of the GO. The variation in the duration of time for the $O_3$ irradiation resulted in a small change in total oxygen content, but in a significantly different fraction of each functional group in the GO, which influenced the Sn nanoparticle size and the amount of SnO (and/or $SnO_2$). As a result, the EPD films prepared with the GO that possessed the least amount of carboxylic groups (made by treating GO in an $O_3$ environment for 3 h) showed the best performance, when compared with the nanocomposites composed of untreated GO or GO that was $O_3$-treated for a duration of less than 3 h.

• Journal of the Korean institute of surface engineering
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• v.37 no.3
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• pp.146-151
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• 2004

Indium tin oxide (ITO) is widely used to make a transparent conducting film for various display devices and opto-electric devices. In this study, ITO films on glass substrate were fabricated by inductively coupled plasma (ICP) assisted dc magnetron sputtering. A two-turn rf coil was inserted in the process chamber between the substrate and magnetron for the generation of ICP. The substrates were not heated intentionally. Subsequent post-annealing treatment for as-deposited ITO films was not performed. Low-temperature deposition technique is required for ITO films to be used with heat sensitive plastic substrates, such as the polycarbonate and acrylic substrates used in LCD devices. The surface roughness of the ITO films is also an important feature in the application of OLEDs along with the use of a low temperature deposition technique. In order to obtain optimum ITO thin film properties at low temperature, the depositions were carried out at different condition in changing of Ar and $O_2$ gas mixtures, ICP power. The electrical, optical and structural properties of the deposited films were characterized by four-point probe, UV/VIS spectrophotometer, atomic force microscopy(AFM) and x-ray diffraction (XRD). The electrical resistivity of the films was -l0$^{-4}$ $\Omega$cm and the optical transmittance in the visible range was ＞85%. The surface roughness ( $R_{rms}$) was -20$\AA$.>.

• Journal of the Korean Vacuum Society
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• v.8 no.2
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• pp.141-147
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• 1999

The electrochromic characteristics of tungsten oxide films are largely affected by deposition conditions, such as substrate temperature and gas flow rate and also post-annealing. We have considered gas flow rate and temperature as important factors having an effect on an electrical, optical phenomenon and structural variation of $WO_3$ . The tungsten oxide films were deposited onto ITO(20$\Omega\box$, 1000$\AA$) using rf magnetron sputtering method. In particular, the films deposited at room temperature were annealed at various temperatures in air. All specimens had crystal structure except one being deposited at room temperature with nearly amorphous-like structure. The specimen deposited at $100^{\circ}C$ had a structure in which the increase in deposition temperature. The specimen deposited at $100^{\circ}C$ had a structure in which the cations$(Li^+)$ are easily movable because of void boundaries induced by regularly arrayed large grains. The specimen deposited at $300^{\circ}C$ had a dense structure with small grains but it exhibited the large mobility and charge density in $WO_3$ because of distinct grain boundaries.

• Korean Journal of Materials Research
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• v.26 no.8
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• pp.430-437
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• 2016

Aluminum oxide ($Al_2O_3$) thin films were grown by atomic layer deposition (ALD) using a new Al metalorganic precursor, dimethyl aluminum sec-butoxide ($C_{12}H_{30}Al_2O_2$), and water vapor ($H_2O$) as the reactant at deposition temperatures ranging from 150 to $300^{\circ}C$. The ALD process showed typical self-limited film growth with precursor and reactant pulsing time at $250^{\circ}C$; the growth rate was 0.095 nm/cycle, with no incubation cycle. This is relatively lower and more controllable than the growth rate in the typical $ALD-Al_2O_3$ process, which uses trimethyl aluminum (TMA) and shows a growth rate of 0.11 nm/cycle. The as-deposited $ALD-Al_2O_3$ film was amorphous; X-ray diffraction and transmission electron microscopy confirmed that its amorphous state was maintained even after annealing at $1000^{\circ}C$. The refractive index of the $ALD-Al_2O_3$ films ranged from 1.45 to 1.67; these values were dependent on the deposition temperature. X-ray photoelectron spectroscopy showed that the $ALD-Al_2O_3$ films deposited at $250^{\circ}C$ were stoichiometric, with no carbon impurity. The step coverage of the $ALD-Al_2O_3$ film was perfect, at approximately 100%, at the dual trench structure, with an aspect ratio of approximately 6.3 (top opening size of 40 nm). With capacitance-voltage measurements of the $Al/ALD-Al_2O_3/p-Si$ structure, the dielectric constant of the $ALD-Al_2O_3$ films deposited at $250^{\circ}C$ was determined to be ~8.1, with a leakage current density on the order of $10^{-8}A/cm^2$ at 1 V.

• Journal of the Semiconductor & Display Technology
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• v.8 no.4
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• pp.65-69
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• 2009

Carbon nanotubes (CNTs) were coated with undoped zinc oxide (ZnO) or 5 wt% gallium-incorporated ZnO (GZO) using various deposition conditions. The CNTs were directly grown on conical-type tungsten substrates at $700^{\circ}C$ using inductively coupled plasma-chemical vapor deposition. The pulsed laser deposition technique was used to deposit the ZnO and GZO thin films with very low stress. Field-emission scanning electron microscopy and high-resolution transmission electron microscopy were used to monitor the variations in the morphology and microstructure of CNTs prior to and after ZnO or GZO coating. The formation of ZnO and GZO films on CNTs was confirmed using energy-dispersive x-ray spectroscopy. In comparison to the as-grown (uncoated) CNT emitter, the CNT emitter that was coated with a thin (10 nm) GZO film showed remarkably improved field emission characteristics, such as the emission current of $325\;{\mu}A$ at 1 kV and the threshold field of $1.96\;V/{\mu}m$ at $0.1\;{\mu}A$, and it also exhibited the highly stable operation of emission current up to 40 h.

• Progress in Superconductivity
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• v.7 no.1
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• pp.69-76
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• 2005

Complex single buffer composed of yttrium and samarium oxide was deposited on the metallic substrates by MOCVD (metal organic chemical vapor deposition) method using single liquid source. Two different types of the substrates with in-plane textures of about $8{\sim}10$ degree of Ni and $3at.\%W-Ni$ alloy were used. Y(tmhd: 2,2,6,6-tetramethyl-3,5-heptane dionate)$_3$:Sm(tmhd)$_3$ of liquid source was adjusted to 0.4:0.6 to minimize the lattice mismatch between the complex single buffer and the YBCO. The epitaxial growth of $(Y_{x}Sm_{1-x})_{2}O_3$ was achieved at the temperature higher than $500^{\circ}C$ in $O_2$ atmosphere. However, it was found that the formation of NiO accelerated with increasing deposition temperature. By supplying $H_{2}O$ vapor, this oxidation of the substrate could be suppressed throughout the deposition temperatures. We could get the epitaxial growth on pure Ni substrate without the formation of NiO. The competitive (222) and (400) growths were observed at the deposition temperatures of $650\~750^{\circ}C$, but the (400) growth became dominant above $800^{\circ}C$. The $(Y_{x}Sm_{1-x})_{2}O_3$-buffered metallic substrates can be used as the buffer for YBCO coated conductor.