• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.211-211
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• 2014

스퍼터링에 의한 박막의 형성에서 박막의 박리나 기판의 휨은 박막내의 내부 응력과 깊은 관련이 있다. 특히 Ti/TiN구조로 많이 사용되는 TiN은 반도체 barrier 층으로 사용이 되기도 하며 하드 코팅 재료로도 많은 연구가 이루어지고 있다. 특히 TiN에 존재하는 높은 압축응력은 연성기판재나 무른 금속재질의 기판을 휘게도 하며, 심할 경우 박막의 박리 현상이 자주 관찰된다. 이렇게 높은 스트레스를 제어하기 위한 기초 연구로 다양한 금속층 박막의 스트레스와 완화시키기 위한 공정 조건 및 스트레스 특성을 확인하였다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.8 no.4
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• pp.640-644
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• 1998

We have fabricated Sb/SiC(4H) Schottky barrier diode (SBD) of which characteristics compared with that of Ti/SiC(4H) SBD. The donor concentration of the n-type SiC(4H) obtained by capacitance-voltage (C-V) measurement was about $2.5{\times}10 ^{17}{\textrm}cm^{-3}$. The ideality factors of 1.31 was obtained from the slope of forward current-voltage (I-V) characteristics of Sb/SiC(4H) SBD at low current density. The breakdown field of Sb/SiC(4H) SBD under the reverse bias voltage was about $4.4{\times}10^2V$/cm. The built-in potential and the Schottky barrier height (SBH) of Sb/SiC(4H) SBD were 1.70V and 1.82V, respectively, which were determined by the analysis of C-V characteristics. The Sb/SiC(4H) SBH of 1.82V was higher than Ti/SiC(4H) SBH of 0.91V. However, the current density and reverse breakdown field of Sb/SiC(4H) were low as compared with those of Ti/SiC(4H). The Sb/SiC(4H), as well as the Ti/SiC(4H), can be utilized as the Shottky barrier contact for the high-power electronic device.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.4
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• pp.378-383
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• 2004

Tungsten is widely used as a plug for the multi-level interconnection structures. However, due to the poor adhesive properties of tungsten(W) on SiO$_2$ layer, the Ti/TiN barrier layer is usually deposited onto SiO$_2$ for increasing adhesion ability with W film. Generally, for the W-CMP(chemical mechanical polishing) process, the passivation layer on the tungsten surface during CMP plays an important role. In this paper, the effect of oxidant on the polishing selectivity of W/Ti/TiN layer was investigated. The alumina(A1$_2$O$_3$)-based slurry with $H_2O$$_2$ as the oxidizer was used for CMP applications. As an experimental result, for the case of 5 wt％ oxidizer added, the removal rates were improved and polishing selectivity of 1.4:1 was obtained. It was also found that the CMP characteristics of W and Ti metal layer including surface roughness were strongly dependent on the amounts of $H_2O$$_2$ oxidizer.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.37 no.1
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• pp.88-93
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• 2024

To evaluate the possibility as a multi-level memory medium for the Ge₂Sb₂Te₅/TiN/W-doped Ge₂Sb₂Te₅ cell structure, the crystallization rate and stabilization characteristics according to voltage (V)- and current (I)- pulse sweeping were investigated. In the cell structures prepared by a magnetron sputtering system on a p-type Si (100) substrate, the Ge₂Sb₂Te₅ and W-doped Ge₂Sb₂Te₅ thin films were separated by a barrier metal, TiN, and the individual thicknesses were varied, but the total thickness was fixed at 200 nm. All cell structures exhibited relatively stable multi-level states of high-middle-low resistance (HR-MR-LR), which guarantee the reliability of the multilevel phase-change random access memory (PRAM). The amorphousto-multilevel crystallization rate was evaluated from a graph of resistance (R) vs. pulse duration (T) obtained by the nanoscaled pulse sweeping at a fixed applied voltage (12 V). For all structures, the phase-change rates of HR→MR and MR→LR were estimated to be approximately t<20 ns and t<40 ns, respectively, and the states were relatively stable. We believe that the doublestack structure of an appropriate Ge-Sb-Te film separated by barrier metal (TiN) can be optimized for high-speed and stable multilevel PRAM.

• Korean Journal of Materials Research
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• v.3 no.6
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• pp.661-667
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• 1993

Effects of $SiH_4//WF_6$(=R) ratio on the electrical properties of W films such as resistvity, contact resistance, junction leakage current in the selective W CVD technology for contact barrier metal were investigated with the emphasis on the role of $\alpha$-W Resistivity of W increases with increasing R, which is primarily due to the phase transformation from $\alpha$-W to , $\alpha$-W. $\alpha$-W found in the SiH4 reduced CVD W film is stabilized by Si incorporated into the W film rather than by oxygen. $\alpha$-W is found in the W film deposited on the Si substrate for high R, while $\alpha$-W is not found in the W film deposited on the TiN substrate even for high R. Also junction leakages increase with increasing R, which is caused not only by the vertical Si consumption but also the lateral Si consumption.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.290.1-290.1
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• 2013

The electrical characterization of Au islands on TiO2 at nanometer scale (as a Schottky nanodiode) has been studied with conductive atomic force microscopy in ultra-high vacuum. The diverse sizes of the Au islands were formed by using self-assembled patterns on n-type TiO2 semiconductor film using the Langmuir-Blodgett process. Local conductance images showing the current flowing through the TiN coated AFM probe to the surface of the Au islands on TiO2 was simultaneously obtained with topography, while a positive sample bias is applied. The boundary of the Au islands revealed a higher current flow than that of the inner Au islands in current AFM images, with the forward bias presumably due to the surface plasmon resonance. The nanoscale Schottky barrier height of the Au/TiO2 Schottky nanodiode was obtained by fitting the I-V curve to the thermionic emission equation. The local resistance of the Au/TiO2 nanodiode appeared to be higher at the larger Au islands than at the smaller islands. The results suggest that conductive atomic force microscopy can be used to reveal the I-V characterization of metal size dependence and the electrical effects of surface plasmon on a metal-semiconductor Schottky diode at nanometer scale.

• Electrical & Electronic Materials
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• v.9 no.10
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• pp.991-1000
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• 1996

PbTiO$_{3}$-PbZrO$_{3}$-Pb(Ni$_{1}$3/Nb$_{2}$3/O$_{3}$) (PZT-PNN) thin films were prepared from corresponding metal organics partially stabilized with diethanolamine by the sol-gel spin coating method. Each mol ratio of PT:PZ:PNN solutions were #1(50:40:10), #2(50:30:20), #3(45:35:20), #4(40:40:20), #5(40:50:10), #6(35:45:20) and #7(30:50:20) respectively. The spin-coated PZT-PNN films were heat-treated at 350.deg. C for decomposition of residual organics, and were sintered from 450.deg. C to 750.deg. C for crystallization. The substrates, such as Pt and Pt/TiN/Ti/TiN/Si were used for the spin coating of PZT PNN films. The perovskite phase was observed in the PZT-PNN films heat-treated at 500.deg. C. The crystalline of the PZT-PNN films was optimized at the sintering of 700.deg. C. By the result of AES analysis, It is confirmed that the films of TiN/Ti/TiN was a good diffusion barrier and that co-diffusion into the each films was not observed.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2002.11a
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• pp.120-122
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• 2002

• Journal of IKEEE
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• v.22 no.2
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• pp.484-487
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• 2018

5 MeV proton-irradiation with total dose of $10^{15}/cm^2$ was performed on AlGaN/GaN-on-Si high electron mobility transistors (HEMTs) with various gate metals including Ni, TaN, W, and TiN to investigate the degradation characteristics. The positive shift of pinch-off voltage and the reduction of on-current were observed from irradiated HEMTs regardless of a type of gate materials. Hall and transmission line measurements revealed the reduction of carrier mobility and sheet charge concentration due to displacement damage by proton irradiation. The shift of pinch-off voltage was dependent on Schottky barrier heights of gate metals. Gate leakage and capacitance-voltage characteristics did not show any significant degradation demonstrating the superior radiation hardness of Schottky gate contacts on GaN.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.399-399
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• 2013

Metal silicides는 Si 기반의microelectronic devices의 interconnect와 contact 물질 등에 사용하기 위하여 그 형성 mechanism과 전기적 특성에 대한 연구가 많이 이루어지고 있다. 이 중 Rare-earth(RE) silicides는 저온에서 silicides를 형성하고, n-type Si과 낮은 Schottky Barrier contact (~0.3 eV)을 이룬다. 또한 낮은 resistivity와 Si과의 작은 lattice mismatch, 그리고 epitaxial growth의 가능성, 높은 thermal stability 등의 장점을 갖고 있다. RE silicides 중 ytterbium silicide는 가장 낮은 electric work function을 갖고 있어 n-channel schottky barrier MOSFETs의 source/drain으로 주목받고 있다. 또한 Silicon 기반의 CMOSFETs의 성능 향상 한계로 인하여 germanium 기반의 소자에 대한 연구가 이루어져 왔다. Ge 기반 FETs 제작을 위해서는 낮은 source/drain series/contact resistances의 contact을 형성해야 한다. 본 연구에서는 저접촉 저항 contact material로서 ytterbium germanide의 가능성에 대해 고찰하고자 하였다. HRTEM과 EDS를 이용하여 ytterbium germanide의 미세구조 분석과 면저항 및 Schottky Barrier Heights 등의 전기적 특성 분석을 진행하였다. Low doped n-type Ge (100) wafer를 1%의 hydrofluoric (HF) acid solution에 세정하여 native oxide layer를 제거하고, 고진공에서 RF sputtering 법을 이용하여 ytterbium 30 nm를 먼저 증착하고, 그 위에 ytterbium의 oxidation을 방지하기 위한 capping layer로 100 nm 두께의 TiN을 증착하였다. 증착 후, rapid thermal anneal (RTA)을 이용하여 N2 분위기에서 $300{\sim}700^{\circ}C$에서 각각 1분간 열처리하여 ytterbium germanides를 형성하였다. Ytterbium germanide의 미세구조 분석은 transmission electron microscopy (JEM-2100F)을 이용하였다. 면 저항 측정을 위해 sulfuric acid와 hydrogen peroxide solution (H2SO4:H2O2=6:1)에서 strip을 진행하여 TiN과 unreacted Yb을 제거하였고, 4-point probe를 통하여 측정하였다. Yb germanides의 면저항은 열처리 온도 증가에 따라 감소하다 증가하는 경향을 보이고, $400{\sim}500^{\circ}C$에서 가장 작은 면저항을 나타내었다. HRTEM 분석 결과, deposition 과정에서 Yb과 Si의 intermixing이 일어나 amorphous layer가 존재하였고, 열처리 온도가 증가하면서 diffusion이 더 활발히 일어나 amorphous layer의 두께가 증가하였다. $350^{\circ}C$ 열처리 샘플에서 germanide/Ge interface에서 epitaxial 구조의 crystalline Yb germanide가 형성되었고, EDS 측정 및 diffraction pattern을 통하여 안정상인 YbGe2-X phase임을 확인하였다. 이러한 epitaxial growth는 면저항의 감소를 가져왔으며, 열처리 온도가 증가하면서 epitaxial layer가 증가하다가 고온에서 polycrystalline 구조의 Yb germanide가 형성되어 면저항의 증가를 가져왔다. Schottky Barrier Heights 측정 결과 또한 면저항 경향과 동일하게 열처리 증가에 따라 감소하다가 고온에서 다시 증가하였다.