• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.860-863
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• 2007

ZnO nano film for transparent thin film transistors is prepared by injection type source delivery system of atomic layer deposition. By using this delivery system the source delivery pulse time can dramatically be reduced to 0.005s in ALD system. ZnO nanofilms obtained at $150^{\circ}C$ are characterized.

• Journal of the Semiconductor & Display Technology
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• v.20 no.4
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• pp.157-160
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• 2021

As an insulator for a thin film transistor(TFT) and an encapsulation material of organic light emitting diode(OLED), aluminum oxide (Al₂O₃) has been widely studied using several technologies. Especially, in spite of low deposition rate, atomic layer deposition (ALD) has been used as a process method of Al₂O₃ because of its low process temperature and self-limiting reaction. In the Al₂O₃ deposition by ALD method, Ar Purge had some crucial effects on the film properties. After reaction gas is injected as a formation of pulse, an inert argon(Ar) purge gas is injected for gas desorption. Therefore, the process parameter of Ar purge gas has an influence on the ALD deposited film quality. In this study, Al₂O₃ was deposited on glass substrate at a different Ar purge time and its structural characteristics were investigated and analyzed. From the results, the growth rate of Al₂O₃ was decreased as the Ar purge time increases. The surface roughness was also reduced with increasing Ar purge time. In order to obtain the high quality Al₂O₃ film, it was known that Ar purge times longer than 15 sec was necessary resulting in the self-limiting reaction.

• Bulletin of the Korean Chemical Society
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• v.34 no.4
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• pp.1221-1224
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• 2013

The atomic layer deposition (ALD) of $ZrO_2$ was conducted in ultrahigh vacuum (UHV) conditions. The surface was exposed to $ZrCl_4$ and $H_2O$ in sequence and the surface species produced after each step were identified in situ with X-ray photoelectron spectroscopy (XPS). $ZrCl_4$ is molecularly adsorbed at 140 K on the $SiO_2$/Si(111) surface covered with OH groups. When the surface is heated to 300 K, $ZrCl_4$ loses two Cl atoms to produce $ZrCl_2$ species. Remaining Cl atoms of $ZrCl_2$ species can be completely removed by exposing the surface to $H_2O$ at 300 K followed by heating to 600 K. The layer-by-layer deposition of $ZrO_2$ was successfully accomplished by repeated cycles of $ZrCl_4$ dosing and $H_2O$ treatment.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.253-253
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• 2013

본 실험에서는 전구체(Precursor)로 TMA (Tris methyl Aluminum)를 사용한 ALD (Atomic Layer Deposition)와 PEALD (Plasma Enhanced Atomic Layer Deposition) 공정 중 발생하는 입자(particle)를 ISPM (In-Situ Particle Mornitor)로 관찰하였다. ALD과 PEALD 공정에서 Al2O3 박막을 형성하기 위해서 반응가스(Reactant)로 각 각 H2O와 O2 plasma를 사용하였다. 이러한 차이로 인해서 진공 챔버(Vacuum Chamber) 안에서의 각기 다른 매커니즘에 의해서 Al2O3의 박막이 형성된다. 또한 공정 중 발생할 수 있는 파티클(Particle) 생성 매커니즘의 차이점을 가진다. ALD의 경우 전구체와 반응가스 사이에 충분한 purge가 이루어지지 않거나 dead zone이 존재할 경우 라인과 챔버 상에 잔류한 전구체와 반응가스에 의해서 불완전한 반응물로 파티클이 생성될 수 있다. 반면 PEALD 경우는 반응가스(Reactant)로 O2 plasma를 극부(localization)적으로 형성하여 박막을 형성하므로 반응가스의 잔류의 영향은 없으나 고에너지의 플라즈마에 의해서 물리적 영향에 의한 파티클이 생성될 수 있다. 공정 중 발생하는 입자(Particle)은 수율 감소와 박막의 물성에 영향을 미칠 수 있다. 그러므로 두 공정 중 발생하는 파티클을 ISPM으로 관찰하였고, 각 공정에서 형성된 박막의 두께 균일도, 표면의 형상(morphology), 화학적 조성 및 전기적 특성을 측정하였다. 이를 통해서 ALD와 PEALD의 파티클과 박막특성을 비교하였다.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.211.1-211.1
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• 2014

Recently, the scaling of conventional planar NAND flash devices is facing its limits by decreasing numbers of electron stored in the floating gate and increasing difficulties in patterning. Three-dimensional vertical NAND devices have been proposed to overcome these issues. Atomic layer deposition (ALD) is the most promising method to deposit charge trap layer of vertical NAND devices, SiN, with excellent quality due to not only its self-limiting growth characteristics but also low process temperature. ALD of silicon nitride were studied using NH3 and silicon chloride precursors, such as SiCl4[1], SiH2Cl2[2], Si2Cl6[3], and Si3Cl8. However, the reaction mechanism of ALD silicon nitride process was rarely reported. In the present study, we used density functional theory (DFT) method to calculate the reaction of silicon chloride precursors with a silicon nitride surface. DFT is a quantum mechanical modeling method to investigate the electronic structure of many-body systems, in particular atoms, molecules, and the condensed phases. The bond dissociation energy of each precursor was calculated and compared with each other. The different reactivities of silicon chlorides precursors were discussed using the calculated results.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.305.2-305.2
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• 2016

Tin monosulfide (SnS) is one promising candidate absorber material which replace the current technology based on cadmium telluride (CdTe) and copper indium gallium sulfide selenide (CIGS) for its suitable optical band gap, high absorption coefficient, earth-abundant, non-toxic and cost-effective. During past years work, thin film solar cells based on SnS films had been improved to 4.36% certified efficiency. In this study, Tin monosul fide was obtained by atomic layer deposition (ALD) using the reaction of Tetrakis (dimethylamino) tin (TDMASn, [(CH3)2N]4Sn) and hydrogen sulfide (H2S) at low temperatures (100 to 200 oC). The direct optical band gap and strong optical absorption of SnS films were observed throughout the Ultraviolet visible spectroscopy (UV VIS), and the properties of SnS films were analyzed by sanning Electron Microscope (SEM) and X-Ray Diffraction (XRD).

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.166.2-166.2
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• 2014

In this work, we demonstrated a facile and effective method for deposition of metal tetraphenylporphyrin (MTPP) thin film by a combined a thermal evaporation (TE) and atomic layer deposition (ALD). For the deposition of Zn-TPP thin film, Tetraphenylporphyrin (TPP) and diethyl zinc (DEZ) were used as organic and inorganic materials, respectively. Optimum conditions for the deposition of Zn-TPP thin film were established systematically: (1) the exposure time of DEZ as inorganic precursor and (2) the substrate temperature were adjusted, respectively. As a result, we verified that the surface reaction between organic semiconductor (TPP) and metal atom (Zn) was ALD process. In addition, we calculated activation energy by using Arrhenius equation for the substrate temperature versus area change rate of pyrrolic nitrogen. The surface and interface reactions between TPP with Zn were investigated by X-ray photoelectron spectroscopy, Raman spectroscopy, UV-vis spectroscopy, and scanning electron microscopy. These results show a facile and well-controllable fabrication technique for the metal-organic thin film for future electronic applications.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.565-566
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• 2006

In this work, We study electrical characterization of $HfO_2$/Hf/Si films grown by Atomic Layer Deposition(ALD). Through AES(Auger Electron Spectroscopy), capacitance-voltage(C-V) and current-voltage(I-V) analysis, the role of Hf layer for the better $HfO_2$/Si interface property was investigated. We found that Hf metal layer in our structure effectively suppressed the generation of interfacial $SiO_2$ layer between $HfO_2$ film and silicon substrate.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.591-592
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• 2012

• Bulletin of the Korean Chemical Society
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• v.31 no.9
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• pp.2503-2508
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• 2010

ZnO thin films were grown on Si or $SiO_2$/Si substrates, at growth temperatures ranging from 150 to $400^{\circ}C$, by atomic layer deposition (ALD) using diethylzinc and water. Despite the large band gap of 3.3 eV, the ALD ZnO films show high n-type conductivity, i.e. low resistivity in the order of $10^{-3}\;{\Omega}cm$. In order to understand the high conductivity of ALD ZnO films, the films were characterized with X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, elastic recoil detection, Rutherford backscattering, Photoluminescence, and Raman spectroscopy. In addition, the various analytical data of the ZnO films were compared with those of ZnO single crystal. According to our analytical data, metallic zinc plays an important role for the high conductivity in ALD ZnO films. Therefore when the metallic zinc was additionally oxidized with ozone by a modified ALD sequence, the resistivity of ZnO films could be adjusted in a range of $3.8{\times}10^{-3}\;{\sim}\;19.0\;{\Omega}cm$ depending on the exposure time of ozone.