• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.85-85
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• 2012

NiO는 니켈 공공과 침입형 산소 이온에 의한 비화학적양론 특성 때문에 자발적으로 p-형 반도체 특성을 나타내는 것으로 알려져 있다. NiO는 3.7 eV 의 넓은 밴드갭을 가지고 있어 투명소자를 위한 hole injection layer 나 hole transport layer로 사용하기 위한 연구가 많이 이루어지고 있다. 또한, 안정적인 p-형 반도체 특성은 n-형 산화물 반도체와의 접합을 통해 복합소자의 구현이 용이하기 때문에, ZnO 등과의 접합을 통한 소자 구현이 가능하다.[1] 하지만, 기존의 많은 연구에서는 내부의 결함이 많이 존재하는 다결정 박막을 사용하였기 때문에, 전하의 이동에 제한이 발생해, 충분한 소자 특성을 나타내지 못하였다. 최근 Dutta의 연구에 의하면, 결정질 사파이어 기판위에 박막을 성장할 경우 [111] 방향으로 우선 배향성을 가진 NiO 박막을 얻을 수 있다고 알려져 있다.[2] 본 실험에서는 NiO 박막을 이용한 PN 접합소자 구현을 위해 사파이어 위에 p-NiO 박막을 에피택셜하게 성장한 후 구조적 특성을 분석하였으며, n-ZnO 박막을 그 위에 성장하여 소자를 제작하였다. 그 결과 ZnO 또한 에피택셜한 성장을 하는 것을 확인할 수 있었다. 성장순서에 따른 PN 접합구조 특성을 확인하기 위해 사파이어 위에 ZnO 를 성장시킨 후 NiO 를 성장시킨 결과 NiO 박막의 우선성장 방향이 [100]으로 변하는 것을 확인할 수 있었다.

• Proceedings of the Materials Research Society of Korea Conference
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• 2005.05a
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• pp.231-231
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• 2005

• Journal of the Korean Ceramic Society
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• v.52 no.4
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• pp.290-293
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• 2015

The properties of the IZTO thin films on the glass were studied with a variation of the $SiO_2$ buffer layer thickness. $SiO_2$ buffer layers were deposited by plasma-enhanced chemical vapor deposition (PECVD) on the glass, and the In-Zn-Tin-Oxide (IZTO) thin films were deposited on the buffer layer by RF magnetron sputtering. All the IZTO thin films with the $SiO_2$ buffer layer are shown to be amorphous. Optimum $SiO_2$ buffer layer thickness was obtained through analyzing the structural, morphological, electrical, and optical properties of the IZTO thin films. As a result, the IZTO surface roughness is 0.273 nm with a sheet resistance of $25.32{\Omega}/sq$ and the average transmittance is 82.51% in the visible region, at a $SiO_2$ buffer layer thickness of 40 nm. The result indicates that the uniformity of surface and the properties of the IZTO thin film on the glass were improved by employing the $SiO_2$ buffer layer and the IZTO thin film can be applied well to the transparent conductive oxide for display devices.

• Journal of the Korean Ceramic Society
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• v.43 no.1 s.284
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• pp.42-47
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• 2006

In this paper, we prepared high-quality ZnO thin films for application of FBAR (Film Bulk Acoustic Resonator) by using pulse DC magnetron sputtering. To prevent the formation of low dielectric layers between metal and piezoelectric layer, Ru film of 30 nm thickness was used as a buffer layer. In addition we investigated the influence of annealing condition with various temperatures. As the annealing temperature increased, the crystalline orientation with the preference of (002) c-axis and resistance properties improved. The single resonator which was fabricated at $500^{\circ}C$ exhibited the resonance frequency and the return loss 0.99 GHz and 15 dB, respectively. This work demonstrates potential feasibility for the use of thin film Ru buffer layers and the optimization of annealing condition.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.2
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• pp.440-448
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• 2004

In this paper, to make a solar cell of II-Ⅵ ZnTe compound semiconductor, we studied for the property of the transparent electrode(AZO) and Buffer layer(ZnO), and for reducing the energyband gap of optical absorber layer which are most effective on its efficiency. The ZnTe thin film was used the optical absorber layer of solar cell. Zn and Te were deposited using the co-sputtering method. The thin film was sputtered RF power of Zn/50W and Te/30W, respectively and a substrate temperature of foot under Ar atmosphere of 10mTorr. The energy band gap of the thin film was 1.73ev Then the thin film was annealed at $400^{\circ}C$ for 10sec under a vacuum atmosphere. The energy band gap of 1.67eV was achieved and the film composition ratio of Zn and Te was 32% and 68%. At the best condition, the Solar Cell was manufactured and the efficiency of 6.85% (Voc: 0.69V, Jsc: 21.408㎃/$cm^2$, Fill factor (FF): 0.46) was achieved.

• Applied Microscopy
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• v.25 no.3
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• pp.82-89
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• 1995

High resolution transmission electron microscopic observations on quaternary $Zn_{1-x}Mg_{x}S_y$ $S_{1-y}$(x=0.13, y=0.16) on (001) GaAs substrate grown up to $1.2{\mu}m$ with 20nm ZnSe buffer layer at $300^{\circ}C$ by RIBER MBE system which has a single growth chamber were investigated by HRTEM working at 300kV with point resolution of 0.18nm. The ZnSe buffer layer maintains the coherency with the GaAs substrate. The stacking faults had begun at ZnSe buffer/$Zn_{1-x}Mg_{x}S_{y}S_{1-y}$ interface, whose length and spacing became larger than 60nm and wider than 40nm, respectively. The inverse triangular stacking fault was bounded by stacking faults which were formed on {111} planes with different variants. There exists rare stacking faults inside the triangular defect. The epilayer surrounded by the straight stacking faults, which had formed in the same direction, became the columnar structure.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.31 no.4
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• pp.221-225
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• 2018

In this work, in order to effectively improve the electrical conductivity and visible light transmittance of ZnO thin films, ZnO single layer and ZnO/Ag bi-layer films were deposited on glass substrates by radio frequency and direct current magnetron sputtering, and then, the effects of an Ag buffer layer and electron beam irradiation on the electrical and optical properties of the films were investigated. The observed results indicate that ZnO 100 nm / Ag 7 nm films show higher opto-electrical performance than the ZnO single layer film. In addition, electron beam irradiation also effectively enhanced the visible transmittance and electrical conductivity of the ZnO/Ag bi-layer films.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.322-323
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• 2005

We deposited Zinc oxide (ZnO) thin films on Ru buffer layer in order to protect the amorphous layer between ZnO and Al interface. In X-ray diffraction (XRD) pattern, it was observed that increase of (002)-orientation by the variation of annealing treatment temperature. Also, surface roughness and specific resistance were increased by annealing treatment but full width at half maximum (FWHM) was decreased. In film bulk acoustic resonators (FBARs) fabricated from these results, we finally confirmed that the resonant frequency of 0.89 GHz without its shift was measured.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2003.12a
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• pp.59-63
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• 2003

체적 음향파 공진기(Film bulk acoustic resonator, FBAR)는 2~10 Ghz 대역의 차세대 이동 통신용 구현에 필수적인 부품이기 때문에 국내외에서 활발한 연구가 진행되고 있다. 본 논문에서는 FBAR 소자 제조를 위한 연구에서 원자층 증착(Atomic layer deposition, ALD) 방법에 의한 ZnO buffer layer 위에 스퍼터링 방법을 이용한 2-step 방법을 사용하여 제조하였다. ALD를 이용한 ZnO buffer layer는 diethylzinc(DEZn)/$H_2O$를 순차적으로 주입하여 증착하였다. 이 때 두 원료물질 사이에 고순도 Ar 가스를 purge gas로 사용하였다. 원료의 주입시간은 1초, 원료간 purge 시간은 23 초로 하고 증착하였다. 2-step 방법을 이용할 경우, 스퍼터링 방법만을 이용하였을 때 보다 우수한 c-축 배향성 및 박막의 표면형상이 관찰되었다. 2-step 방법을 FBAR 소자 제작에 적용할 경우 보다 우수한 특성의 공진기를 제작할 수 있을 것으로 기대된다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.106-106
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• 2014

Atomic layer deposition 방법으로 증착시킨 ZnO 박막은 다양한 종류의 태양전지에서 TCO, Buffer Layer 등 다양한 층에 활용될 수 있어 최근 많은 주목을 받고 있다. 각 적용분야에 필요한 요구조건에 따라 ZnO의 다양한 물리/화학적 특성은 이에 맞도록 조절될 필요가 있으며, 이는 ALD 공정을 통해 ZnO를 증착할 때도 마찬가지이다. 본 발표에서는 ALD를 이용한 ZnO 공정에서 이러한 물리/화학적 특성을 조절하기 위하여 시도되고 있는 precursor/reactant의 선정, 공정조건의 조절, 새로운 precursor의 적용 예를 들고, 특히 전기적 특성에 초점을 맞추어 이들이 증착된 ZnO 박막 특성에 미치는 영향을 조사하였다.