• 전자공학회논문지D
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• 제35D권6호
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• pp.46-53
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• 1998

저온 공정으로 제작되는 다결정 실리콘 박막 트랜지스터의 활성층을 이중 활성층(a-Si/a-SiN/sub x/)으로 제작하는 공정을 제안하고 다결정 실리콘 박막 트랜지스터를 제작하였다. 본 논문에서는 활성층의 아래쪽 실리콘 박막에 약간의 질소기를 첨가한 후 그 위에 순수한 비정질 실리콘 박막을 증착하여 엑시머 레이저의 에너지로 비정질 실리콘 박막을 결정화하여 사용하였다. 이중 활성층 (a-Si/a-SiN/sub x/)의 경우, 하부층의 NH₃/SiH₄ 유속비가 증가함에 따라, 상부 a-Si 층의 결정 성장이 촉진됨을 알 수 있었으나, n/sup +/ poly-SiN/sub x/ 층의 전도도 특성을 고려해 볼 때, NH₃/SiH₄ 유속비는 0.11의 상한치를 가짐을 알 수 있었다. 전계 방출 전류에 영향을 미치는 광학적 밴드갭의 경우, poly-Si 박막에 비해 증가하였으며, NH₃/SiH₄ 유속비가 0.11 이하에서도 0.1eV 정도의 증가를 보여, 이로 인하여 소자 제작시 전계 방출 전류가 억제될 것을 예상할 수 있다.

• Journal of Electrochemical Science and Technology
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• 제8권3호
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• pp.206-214
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• 2017

SnS films have been prepared by electrodeposition technique onto Cu and ITO substrates using acidic solutions containing tin chloride and sodium thiosulfate with sodium citrate as an additive. The effects of sodium citrate on the electrochemical behavior of electrolyte bath containing tin chloride and sodium thiosulfate were investigated by cyclic voltammetry and chronoamperometry techniques. Deposited films were characterized by XRD, FTIR, SEM, optical, photoelectrochemical, and electrical measurements. XRD data showed that deposited SnS with sodium citrate on both substrates were polycrystalline with orthorhombic structures and preferential orientations along (111) directions. However, SnS films with sodium citrate on Cu substrate exhibited a good crystalline structure if compared with that deposited on ITO substrates. FTIR results confirmed the presence of SnS films at peaks 1384 and $560cm^{-1}$. SEM images revealed that SnS with sodium citrate on Cu substrate are well covered with a smooth and uniform surface morphology than deposited on ITO substrate. The direct band gap of the films is about 1.3 eV. p-type semiconductor conduction of SnS was confirmed by photoelectrochemical and Hall Effect measurements. Electrical properties of SnS films showed a low electrical resistivity of $30{\Omega}cm$, carrier concentration of $2.6{\times}10^{15}cm^{-3}$ and mobility of $80cm^2V^{-1}s^{-1}$.

• 대한화학회지
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• 제24권4호
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• pp.295-301
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• 1980

고체전해질 $RbAg_4I_5$의 단결정을 키워서 온도에 따른 전기전도율의 변화를 퍼텐티오메트릭 4-전극방법으로 측정하고 $Ag/RbAg_4I_5$, 계면에 대한 전기화학적 성질을 순환전압전류법으로 조사하였다. 25$^{\circ}C$에서 단결정의 비전기전도율은 $0.284\pm0.003 ohm^{-1}cm^{-1}이었고 \;Ag^+$이온의 이동에 대하여 계산된 활성화에너지는 1.70kcal/mol로서 다결정 시료에 대한 값들과 거의 일치하였다. 순환전압전류법 실험결과 은 기준전극에 대한 전위 0볼트 이하에서는 은 전극에서 $Ag^+$ 이온의 가역적환원이 일어났고 +0.67볼트 이상의 전위에서 요오드화 이온이 산화되어 요오드가 유리되었다. 은의 산화 전위에서 은 전극은 작은 양극전류만을 나타내었으나 환원전위에서 은 전극의 표면에 환원 석출된 은은 다시 양극 전위로 돌아갈 때 아주 큰 산화전류를 나타내었다.

• 대한화학회지
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• 제21권5호
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• pp.339-352
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• 1977

소성변형에 대한 저자들의 이론(제1보)을 요업재료, 금속, 합금 및 단결정들에 적용하였다. 그 결과 다중 결정에서는 dislocation 운동과 grain boundary 운동이 실험조건에 따라 함께 또는 분리되어 나타나는 반면 단결정에서는 dislocation 운동만 나타났다. 유동식에 나타나는 파라미터$({\alpha}_{d1},\;1/{\beta}_{d1})와\;({\alpha}_{gj}/X_{gj},\;1/{\beta}_{gj})$ (j = 1 or 2) 및 활성화엔탈피 ${\Delta}H_{k1}^{\neq}$ (k = d 혹은 g)를 구하여 예측한 소성변형은 실험과 잘 일치함을 보았다. 여기서 첨자 d1는 첫번째의 dislocation 유동단위, gj는 j번째 grain boundary 유동단위를 나타낸다. 활성화엔탈피에 대하여 ${\Delta}H_{d1}^{\neq}$는 bulk의 자체확산에 대한 활성화엔탈피와 일치하고 ${\Delta}H_{g1}^{\neq}$는 grain boundary 자체확산에 대한 활성화엔탈피와 일치하였다. 이 사실은 저자들의 이론의 정당성을 보이고 있다.

• 전자공학회논문지D
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• 제35D권10호
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• pp.83-90
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• 1998

MOS 캐패시터의 게이트 전극을 비정질 상태의 실리콘으로 형성하여 GOI(Gate Oxide Integrity)특성에 미치는 불순물 활성화 열처리의 효과를 조사하였다. LPCVD(Low Pressure Chemical Vapor Deposition) 방법으로 증착한 비정질 실리콘 게이트 전극은 활성화 열처리에 의하여 다결정 실리콘 상태로 구조가 변화하며, 불순물 원자의 활성화가 충분히 이루어졌다. 또한, 비정질 상태의 게이트 전극은 커다란 압축 응력(compressive stress)을 가지지만, 활성화 열처리 온도가 700℃에서 900℃로 증가함에 따라서 응력이 완화되었고 게이트 전극의 저항도 감소하는 특성을 보였다. 또한 얇은 게이트 산화막의 신뢰성 및 산화막의 계면특성은 활성화 열처리 온도에 크게 의존하고 있었다. 900℃에서 활성화 열처리를 한 경우가 700℃에서 열처리한 경우보다 산화막내에서의 전하 포획 특성이 개선되었으며, 산화막의 신뢰성이 향상되었다. 특히, TDDB 방법으로 예측한 게이트 산화막의 수명은 700℃의 열처리에서는 3×10/sup 10/초였지만, 900℃에서의 열처리에서는 2×10/sup 12/초로 현저하게 개선되었다. 그리고, 산화막 계면에서의 계면 전하 밀도는 게이트의 응력 완화에 따라서 개선되었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 C
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• pp.1968-1970
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• 1996

We investigate a surface-micromachined polysilicon microgyroscope, whose resonant frequencies are electrostatically-tunable after fabrication. The microgyroscope with two oscillation nudes has been designed so that the resonant frequency in the sensing mode is higher than that in the actuating mode. The microgyroscope has been fabricated by a 4-mask surface-micrormachining process, including the deep RIE of a $6{\mu}m$-thick LPCVD polycrystalline silicon layer. The resonant frequency in the sensing mode has been lowered to that in actuating mode through the adjustment of an inter-plate bias voltage; thereby achieving a frequency matching at 5.8kHz under the bias voltage of 2V in a reduced pressure of 0.1torr. For an input angular rate of $50^{\circ}/sec$, an output signal of 20mV has been measured from the tuned microgyroscope under an AC drive voltage of 2V with a DC bias voltage of 3V.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 C
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• pp.1418-1420
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• 1996

In this paper, structural properties of CdTe thin films and photovoltaic properties of thin film CdS/CdTe solar ceIl prepared by thermal vacuum evaporation were studied. Structural variation with $CdCl_2/heat$ treatment are assessed using x-ray diffraction and scanning electron microscopy. The crystal structure of CdTe films was zincblend type with preferential orientation of the (111) plane parallel to the substrate. The $CdCl_2$ treatment appears to increase the grain size of polycrystalline CdTe thin film. It was found that CdS/CdTe solar cell characteristics were improved by the heat treatment with $CdCl_2$. The conversion efficiency, however, decreased when heat treatment temperature was too high.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.304.1-304.1
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• 2014

Flat-panel displays have been growing as an essential everyday product in the current information/communication ages in the unprecedented speed. The forward-coming applications require light-weightness, higher speed, higher resolution, and lower power consumption, along with the relevant cost. Such specifications demand for a new concept-based materials and applications, unlike Si-based technologies, such as amorphous Si and polycrystalline Si thin film transistors. Since the introduction of the first concept on the oxide-based thin film transistors by Hosono et al., amorphous oxide thin film transistors have been gaining academic/industrial interest, owing to the facile synthesis and reproducible processing despite of a couple of shortcomings. The current work places its main emphasis on the binary oxides composed of ZnO and SnO2. RF sputtering was applied to the fabrication of amorphous oxide thin film devices, in the form of bottom-gated structures involving highly-doped Si wafers as gate materials and thermal oxide (SiO2) as gate dielectrics. The physical/chemical features were characterized using atomic force microscopy for surface morphology, spectroscopic ellipsometry for optical parameters, X-ray diffraction for crystallinity, and X-ray photoelectron spectroscopy for identification of chemical states. The combined characterizations on Zn-Sn-O thin films are discussed in comparison with the device performance based on thin film transistors involving Zn-Sn-O thin films as channel materials, with the aim to optimizing high-performance thin film transistors.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.398.1-398.1
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• 2014

The $Cu_2ZnSnSe_4$ (CZTSe) thin films solar cell is one of the next generation candidates for photovoltaic materials as the absorber of thin film solar cells because it has optimal bandgap (Eg=1.0eV) and high absorption coefficient of $10^4cm^{-1}$ in the visible length region. More importantly, CZTSe consists of abundant and non-toxic elements, so researches on CZTSe thin film solar cells have been increasing significantly in recent years. CZTSe thin film has very similar structure and properties with the CIGS thin film by substituting In with Zn and Ga with Sn. In this study, As-deposited CZTSe thin films have been deposited onto soda lime glass (SLG) substrates at different deposition condition using Pulsed Laser Deposition (PLD) technique without post-annealing process. The effects of deposition conditions (deposition time, deposition temperature) onto the structural, compositional and optical properties of CZTSe thin films have been investigated, without experiencing selenization process. The XRD pattern shows that quaternary CZTSe films with a stannite single phase. The existence of (112), (204), (312), (008), (316) peaks indicates all films grew and crystallized as a stannite-type structure, which is in a good agreement with the diffraction pattern of CZTSe single crystal. All the films were observed to be polycrystalline in nature with a high (112) predominant orientation at $2{\theta}{\sim}26.8^{\circ}$. The carrier concentration, mobility, resistivity and optical band gap of CZTSe thin films depending on the deposition conditions. Average energy band gap of the CZTSe thin films is about 1.3 eV.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2010년도 춘계학술발표대회
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• pp.49.1-49.1
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• 2010

The particle generation during the plasma enhanced process is highly considered as serious problem in the semiconductor manufacturing industry. The material for the plasma processing chamber requires the plasma etching characteristics which are homogeneously etched surface and low plasma etching depth for preventing particulate contamination and high durability. We found that the materials without grain boundaries can prevent the particle generation. Therefore, the amorphous material with the low plasma etching rate may be the best candidate for the plasma processing chamber instead of the polycrystalline materials such as yttria and alumina. Three glasses based on $SiO_2$ and $Al_2O_3$ were prepared with various rare-earth elements (Gd, Y and La) which are same content in the glass. The glasses were plasma etched in the same condition and their plasma etching rate was compared including reference materials such as Si-wafer, quartz, yttria and alumina. The mechanical and thermal properties of the glasses were highly related with cationic field strength (CFS) of the rare-earth elements. We assumed that the plasma etching resistance may highly contributed by the thermal properties of the fluorine byproducts generated during the plasma exposure and it is expected that the Gd containing glass may have the highest plasma etching resistance due to the highest sublimation temperature of $GdF_3$ among three rare-earth elements (Gd, Y and La). However, it is found that the plasma etching results is highly related with the mechanical property of the glasses which indicates the cationic field strength. From the result, we conclude that the glass structure should be analyzed and the plasma etching test should be conducted with different condition in the future to understand the plasma etching behavior of the glasses perfectly.