• 한국전기전자재료학회논문지
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• 제30권1호
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• pp.23-26
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• 2017

Mo doped carbon (C:Mo) thin films were fabricated with various Mo target power densities by unbalanced magnetron sputtering (UBM). The effects of target power density on the surface, structural, and electrical properties of C:Mo films were investigated. UBM sputtered C:Mo thin films exhibited smooth and uniform surfaces. However, the rms surface roughness of C:Mo films were increased with the increase of target power density. Also, the resistivity value of C:Mo film as electrical properties was decreased with the increase of target power density. From the performance of organic thin filml transistor using conductive C:Mo gate electrode, the carrier mobility, threshold voltage, and on/off ratio of drain current (Ion/Ioff) showed $0.16cm^2/V{\cdot}s$, -6.0 V, and $7.7{\times}10^4$, respectively.

• Transactions on Electrical and Electronic Materials
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• 제14권5호
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• pp.250-253
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• 2013

In this paper, we fabricated 3D pillar type silicon-oxide-nitride-oxide-silicon (SONOS) devices for high density flash applications. To solve the limitation between erase speed and data retention of the conventional SONOS devices, bandgap-engineered (BE) tunneling oxide of oxide-nitride-oxide configuration is integrated with the 3D structure. In addition, the tunneling oxide is modulated by another method of $N_2$ ion implantation ($N_2$ I/I). The measured data shows that the BE-SONOS device has better electrical characteristics, such as a lower threshold voltage ($V_{\tau}$) of 0.13 V, and a higher $g_{m.max}$ of 18.6 ${\mu}A/V$ and mobility of 27.02 $cm^2/Vs$ than the conventional and $N_2$ I/I SONOS devices. Memory characteristics show that the modulated tunneling oxide devices have fast erase speed. Among the devices, the BE-SONOS device has faster program/erase (P/E) speed, and more stable endurance characteristics, than conventional and $N_2$ I/I devices. From the flicker noise analysis, however, the BE-SONOS device seems to have more interface traps between the tunneling oxide and silicon substrate, which should be considered in designing the process conditions. Finally, 3D structures, such as the pillar type BE-SONOS device, are more suitable for next generation memory devices than other modulated tunneling oxide devices.

• 한국표면공학회지
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• 제39권6호
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• pp.250-254
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• 2006

Effect of hydrogen partial pressure ratio on the structural and electrical properties of highly c-axis oriented ZnO films deposited by oxygen ion-assisted pulsed filtered vacuum arc at a room temperature was investigated. The hydrogen partial pressure ratio were $1.4%\sim9.8%$ at 40% oxygen pressure ratio. The conductivity of ZnO:H films was increased from 1.4% up to 4.2% due to relatively high carrier mobility caused by improvement of crystallinity While the conductivity of ZnO:H films were decreased over than 4.2% and (0002) orientation was also deteriorated. The lowest resistivity of ZnO:H films was $2.5{\times}10^{-3}\;{\Omega}{\cdot}cm$ at 4.2% of hydrogen pressure ratio. Transmittance of ZnO:H films in visible range was 85% which is lower than that of undoped ZnO films because of declined preferred orientation.

• 한국표면공학회지
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• 제29권6호
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• pp.876-879
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• 1996

The effect of oxygen vacancy and Sn donor on carrier density for Indium Tin oxide (ITO) and Indium oxide (InO) films has been investigated. Hot-cathode Penning discharge sputtering (HC-PDS) in the mixed gasses of argon and oxygen was applied to fabricate the ITO and InO films. Density of oxygen vacancy was estimated using a high-energy ion beam technique. The electrical properties of the films such as resistivity, carrier density and mobility were estimated by Van der Pauw method. The doping efficiency of oxygen vacancy could be obtained from the relationship between oxygen vacancy and carrier density. The doping efficiency of oxygen vacancy for ITO films resulted in a quite small value. Comparing the doping efficiencies of ITO and InO films, the effect of Sn donor on carrier density was also discussed.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.197-197
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• 2012

Device 제작에 사용된 graphene은 일반적인 lithography 공정에서 resist residue에 의한 오염을 피할 수 없으며 이로 인하여 graphene의 pristine한 성질을 잃어버린다. 본 연구에서는 graphene을 저밀도의 argon inductively coupled plasma (Ar-ICP)를 통해 처리함으로서 graphene based back-gated field effect transistor (G-FET)의 특성변화를 유도한 결과에 대해서 보고한다. Argon capacitively coupled plasma (Ar-CCP)은 에 노출된 graphene은 강한 ion bombardment energy로 인하여 쉽게 planar C-C ${\pi}$ bonding (bonding energy: 2.7 eV)이 breaking되어 graphene의 defect이 발생되었다. 하지만 우리의 경우 저밀도의 Ar-ICP가 적용될 때 graphene의 defect이 제한되며 이와 동시에 contamination 만을 제거할 수 있었다. 소자의 전기적 측정 (Gsd-Vbg)을 통하여 contamination으로 인하여 p-doping된 graphene은 pristine 상태로 회복되었으며 mobility도 회복됨이 확인되었다. Ar-ICP를 이용한 graphene cleaning 방법은 저온공정, 대면적 공정, 고속공정을 모두 만족시키며 thermal annealing, electrical current annealing을 대체하여 graphene 기반 소자를 생산함에 있어 쉽고 빠르게 적용할 수 있는 강점이 있다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.289.2-289.2
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• 2016

In-Ga-Zn-O(IGZO) receive great attention as a channel material for thin film transistors(TFTs) as next-generation display panel backplanes due to its superior electrical and physical properties such as a high mobility, low off-current, high sub-threshold slope, flexibility, and optical transparency. For the purpose of fabricating high performance IGZO TFTs, a thermal recovery process above a temperature of $300^{\circ}C$ is required for recovery or rearrangement of the ionic bonding structure. However diffused metal atoms from source/drain(S/D) electrodes increase the channel conductivity through the oxidation of diffused atoms and reduction of $In_2O_3$ during the thermal recovery process. Threshold voltage ($V_{TH}$) shift, one of the electrical instability, restricts actual applications of IGZO TFTs. Therefore, additional investigation of the electrical stability of IGZO TFTs is required. In this paper, we demonstrate the effect of Ti diffusion and modulation of interface traps by carrying out an annealing process on IGZO. In order to investigate the effect of diffused Ti atoms from the S/D electrode, we use secondary ion mass spectroscopy (SIMS), X-ray photoelectron spectroscopy, HSC chemistry simulation, and electrical measurements. By thermal annealing process, we demonstrate VTH shift as a function of the channel length and the gate stress. Furthermore, we enhance the electrical stability of the IGZO TFTs through a second thermal annealing process performed at temperature $50^{\circ}C$ lower than the first annealing step to diffuse Ti atoms in the lateral direction with minimal effects on the channel conductivity.

• 한국전기전자재료학회논문지
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• 제30권8호
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• pp.469-473
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• 2017

We investigated the effect of different thin-film thicknesses (25, 30, and 40 nm) on the electrical performance of solution-processed indium-zinc-oxide (IZO) thin-film transistors (TFTs). The structural properties of the IZO thin films were investigated by atomic force microscopy (AFM). AFM images revealed that the IZO thin films with thicknesses of 25 and 40 nm exhibit an uneven distribution of grains, which deforms the thin film and degrades the performance of the IZO TFT. Further, the IZO thin film with a thickness of 30 nm exhibits a homogeneous and smooth surface with a low RMS roughness of 1.88 nm. The IZO TFTs with the 30-nm-thick IZO film exhibit excellent results, with a field-effect mobility of $3.0({\pm}0.2)cm^2/Vs$, high Ion/Ioff ratio of $1.1{\times}10^7$, threshold voltage of $0.4({\pm}0.1)V$, and subthreshold swing of $0.7({\pm}0.01)V/dec$. The optimization of oxide semiconductor thickness through analysis of the surface morphologies can thus contribute to the development of oxide TFT manufacturing technology.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2010년도 제39회 하계학술대회 초록집
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• pp.309-309
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• 2010

We have investigated the effect of $H_2$ plasma treatment on the BZO (ZnO:B, Boron doped ZnO) thin films. The BZO thin films are prepared by LP-MOCVD (Low Pressure Metal Organic Chemical Vapor Deposition) technique and the samples of BZO thin film are performed with $H_2$ plasma treatment by plasma treatment system with 13.56 MHz as RIE (Reactive Ion Etching) type. After exposing $H_2$ plasma treatment, measurement of transmittance, reflectance and haze spectra in 300~1100 nm, electrical properties as resistivity, mobility and carrier concentration and work function was analysed. Regarding the results of the $H_2$ plasma treatment on the BZO thin films are application to the TCO for solar cells, such as the a-Si thin films solar cell.

• 대한화학회지
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• 제7권1호
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• pp.17-24
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• 1963

本硏究에서는 韓國産 灰重石($CaWO_4$)에 關하여 固相一液相界面에 있어서의 電氣化學的 性質을 電氣泳動法으로 調査하고 한便 浮遊性에 關하여서는 捕收劑로 Dodecyl ammonium chloride(D.A.C.라 略稱)와 Sodium dodecyl sulfate(S.D.S.라 略稱)를 使用하여 Hallimond tube 試驗, 接觸角測定 及 吸着量測定等의 捕收劑 이온이 鑛物表面에 吸着하는데 있어서 電氣的인 相互作用이 重要한 役割을 하고 있다는 것을 實證하였다. 卽 電氣泳動法으로 鑛粒의 水溶液中에 있어서의 mobility를 測定한 結果 灰重石의 境遇에는 $Ca^{++}$ 或은 $WO_4^{--}$이 界面 電氣特性을 決定하는 potental determining ion이라는 것이 確認되었고 水溶液中에 있는 $Ca^{++}$의 增加는 鑛粒界面의 陰電荷를 減少하며 $WO_4^{--}$의 增加는 그 陰電荷를 增加한다는 것을 알수 있다. 이와같은 表面에 "陰이온系"의 S.D.S. 或은 "陽이온系"의 D.A.C.를 作用시키면 當然히 S.D.S.는 $Ca^{++}$의 增加에 따라 吸着量이 增加되어 浮遊性이 增大되고 한便 D.A.C. 때는 反對로 $WO_4^{--}$이 增加하는데 따라 吸着量이 增加되며 따라서 浮遊性도 增大된다고 불수 있고 實地로 捕收劑吸着量의 測定 및 Hallimond tube 實驗은 이것을 立證하고 있다. 이러한 基礎的인 究明은 灰重石浮選理論의 根幹이 되는 것이고 從來의 浮選法 改良에 對한 指針이 될수 있다고 生覺한다.

• 대한전자공학회논문지SD
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• 제45권7호
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• pp.1-8
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• 2008

본 논문에서는 플라스틱 기판에 OTFT를 스위칭 소자로 사용하여 유연한 EPD 패널을 제작하였다. OTFT의 채널 폭과 길이의 비(W/L)는 EPD의 응답속도를 고려하여 15이상으로 설계를 하였다. 게이트전극은 Al, 절연층은 cross-linked PVP, 반도체층은 펜타센, 중간층은 PVA/Acryl를 사용하였다. 플라스틱 기판은 보호층 처리를 통하여 열처리 공정 시 발생하는 입자를 제거하였고, 거친 표면을 평탄화하였다. 반도체층의 크기는 게이트 전극 보다 작도록 제한하여 누설전류를 줄일 수 있었다. EPD-상판과 OTFT-하판 사이에 픽셀전극을 삽입하고 또한 OTFT-하판을 보호하기 위하여 PVA/Acryl로 구성된 중간층을 상빙하였다. 완성된 OTFT-하판에서 OTFT의 이동도는 $0.21cm^2/V.s$, 전류점멸비(Ion/Ioff)는 $10^5$ 이상의 성능을 보였다.