• 제목/요약/키워드: GeSi Alloy

검색결과 40건 처리시간 0.025초

Si0.8Ge0.2계 합금에서 열전특성에 미치는 B의 영향 (Influence of Boron Content on the Thermoelectric Properties of p-type Si0.8Ge0.2 Alloy)

  • 황성두;최우석;박익민;박용호
    • 한국분말재료학회지
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    • 제14권4호
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    • pp.272-276
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    • 2007
  • P-type thermoelectric material $Si_{0.8}Ge_{0.2}$ was sintered by Hot Press process (HP) and the effect of boron ($0.25{\sim}2$ at%) addition on the thermoelectric properties were reported. To enhance the thermoelectric performances, the $Si_{0.8}Ge_{0.2}$, alloys were fabricated by mechanical alloying (MA) and HP. The carrier of p-type SiGe alloy was controlled by B-doping. The effect of sintering condition and thermoelectric properties were investigated. B-doped SiGe alloys exhibited positive seebeck coefficient. The electrical conductivity and thermal conductivity were increased at the small amount of boron content ($0.25{\sim}0.5$ at%). However, they were decreased over 0.5 at% boron content. As a result, the small addition of boron improved the Z value. The Z value of 0.5 at% B doped $Si_{0.8}Ge_{0.2}$ B alloy was $0.9{\times}10{-4}/K$, the highest value among the prepared alloys.

Theoretical Study of Electron Mobility in Double-Gate Field Effect Transistors with Multilayer (strained-)Si/SiGe Channel

  • Walczak, Jakub;Majkusiak, Bogdan
    • JSTS:Journal of Semiconductor Technology and Science
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    • 제8권3호
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    • pp.264-275
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    • 2008
  • Electron mobility has been investigated theoretically in undoped double-gate (DG) MOSFETs of different channel architectures: a relaxed-Si DG SOI, a strained-Si (sSi) DG SSOI (strained-Si-on-insulator, containing no SiGe layer), and a strained-Si DG SGOI (strained-Si-on-SiGe-on-insulator, containing a SiGe layer) at 300K. Electron mobility in the DG SSOI device exhibits high enhancement relative to the DG SOI. In the DG SGOI devices the mobility is strongly suppressed by the confinement of electrons in much narrower strained-Si layers, as well as by the alloy scattering within the SiGe layer. As a consequence, in the DG SGOI devices with thinnest strained-Si layers the electron mobility may drop below the level of the relaxed DG SOI and the mobility enhancement expected from the strained-Si devices may be lost.

다결정 $Ge_{0.2}Si_{0.8}$의 습식 열산화 (Wet oxidation of polycrystalline $Ge_{0.2}Si_{0.8}$)

  • 박세근
    • E2M - 전기 전자와 첨단 소재
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    • 제8권1호
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    • pp.71-76
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    • 1995
  • The thermal oxidation of Ge$_{0.2}$Si$_{0.8}$ in wet ambient has been investigated by Rutherford Backscattering Spectrometry(RBS). A uniform Ge$_{0.2}$Si$_{0.8}$O$_{2}$ oxide is formed at temperatures below 650.deg. C for polycrystalline and below 700.deg. C for single crystalline substrates. At higher temperatures Ge becomes depleted from the oxide and finally SiO$_{2}$ oxide is formed with Ge piled-ub behind it. The transition between the different oxide types depends also on the crystallinity of Ge$_{0.2}$Si$_{0.8}$. When a uniform Ge$_{0.2}$Si$_{0}$8/O$_{2}$ oxide grows, its thickness is proportional to the square root of the oxidation time, which suggests that the rate noting process is the diffusive transport of oxidant across the oxide. It is believed the oxidation is controlled by the competition between the diffusion of Ge or Si in Ge$_{0.2}$Si$_{0.8}$ and the movement of oxidation front.t.oxidation front.t.

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Si-Ge-H-Cl 계를 이용한 자기정렬 HBT용 Si 및 SiGe의 선택적 에피성장 (Selective Epitaxial Growth of Si and SiGe using Si-Ge-H-Cl System for Self-Aligned HBT Applications)

  • 김상훈;박찬우;이승윤;심규환;강진영
    • 한국전기전자재료학회논문지
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    • 제16권7호
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    • pp.573-578
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    • 2003
  • Low temperature selective epitaxial growth of Si and SiGe has been obtained using an industrial single wafer chemical vapor deposition module operating at reduced pressure. Epitaxial Si and heteroepitaxial SiGe deposition with Ge content about 20 % has been studied as extrinsic base for self-aligned heterojunction bipolar transistors(HBTs), which helps to reduce the parasitic resistance to obtain higher maximum oscillation frequencies(f$\_$max/). The dependence of Si and SiGe deposition rates on exposed windows and their evolution with the addition of HCl to the gas mixture are investigated. SiH$_2$Cl$_2$ was used as the source of Si SEG(Selective Epitaxial Growth) and GeH$_4$ was added to grow SiGe SEG. The addition of HCl into the gas mixture allows increasing an incubation time even low growth temperature of 675∼725$^{\circ}C$. In addition, the selectivity is enhanced for the SiGe alloy and it was proposed that the incubation time for the polycrystalline deposit on the oxide is increased probably due to GeO formation. On the other hand, when only SiGe SEG(Selective Epitaxial Growth) layer is used for extrinsic base, it shows a higher sheet resistance with Ti-silicide because of Ge segregation to the interface, but in case of Si or Si/SiGe SEG layer, the sheet resistance is decreased up to 70 %.

$Si_{1-x}Ge_x$ 박막의 Spectroscopic ellisometry 분석 (Characterization of $Si_{1-x}Ge_x$ alloy by Spectroscopic ellisometry)

  • 어윤필;황석희;태흥식;황기웅
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1994년도 추계학술대회 논문집 학회본부
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    • pp.240-242
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    • 1994
  • Spectroscopic ellipsometry(SE) was employed to characterize the Si/$Si_{1-x}Ge_x$ heterostructure. The dielectric function spectrum of $Si_{1-x}Ge_x$ at an arbitrary x value in the spectral range of $1.5{\sim}4.5\;eV$ was computed by EMA (effective medium approximation) model using the available optical constants measured at a number of fixed x values of Ge composition. The thickness and the Ge composition of $Si_{1-x}Ge_x$ measured by SE was compared with those measured by RBS. DC bias effect on the $E_2$ peak of dielectric function spectra was studied.

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리튬이차전지용 다공성 Si-Ge-Al계 음극활물질의 전기화학적 특성 (Effects of Porous Microstructure on the Electrochemical Properties of Si-Ge-Al Base Anode Materials for Li-ion Rechargeable Batteries)

  • 조충래;김명근;손근용;박원욱
    • 한국분말재료학회지
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    • 제24권1호
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    • pp.24-28
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    • 2017
  • Silicon alloys are considered promising anode active materials to replace Li-ion batteries by graphite powder, because they have a relatively high capacity of up to 4200 mAh/g, and are environmentally friendly and inexpensive ECO-materials. However, its poor charge/discharge properties, induced by cracking during cycles, constitute their most serious problem as anode electrode. In order to solve these problems, Si-Ge-Al alloys with porous structure are designed as anode alloy powders, to improve cycling stability. The alloys are melt-spun to obtain the rapidly solidified ribbons, and then ball-milled to make fine powders. The powders are etched using 1 M HCl solution, which gives the powders a porous structure by removing the element Al. Subsequently, in this study, the microstructures and the characteristics of the etched powders are evaluated for application as anode materials. As a result, the etched porous powder shows better electrochemical properties than as-milled Si-Ge-Al powder.

a-SiGe solar cell의 광학적 특성 (Effects of optical properties in hydrogenated amorphous silicon germanium alloy solar cells)

  • 백승조;박태진;김범준
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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    • pp.67.1-67.1
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    • 2010
  • Triple junction solar cell을 위한 a-SiGe middle cell의 조건별 광학적 특성에 관한 연구를 실시하였다. a-SiGe I층은 GeH4 유량, 압력, H2 dilution ratio를 변화시켜 제조하였으며 전기적, 광학적 특성을 비교하여 최종적으로 선택된 조건을 triple junction solar cell에 적용하였다. a-SiGe I층은 Ge contents가 증가함에 따라 band gap은 감소하고 45% 이상의 조건에서는 700nm 전후 파장의 투과율이 감소하며, 압력이 감소함에 따라 band gap은 소폭 감소하나 700nm 전후 파장의 투과율은 증가하였다. 그리고 H2 ratio가 증가함에 따라 band gap은 소폭 감소하나 투과율에는 큰 변화가 없었다. 상기 결과를 바탕으로 최종적으로 선택된 조건에서 triple-junction solar cell을 제작하여 평가한 결과 초기 변환효율 9%의 결과를 얻었다.

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Ge-MOSFETs을 위한 Ni-Co 합금을 이용한 Ni-germanide의 열안정성 개선 (Thermal Stability Improvement of Ni-germanide using Ni-Co alloy for Ge-MOSFETs Technology)

  • 박기영;정순연;장잉이;한인식;이세광;종준;신홍식;김영철;김재준;이가원;왕진석;이희덕
    • 한국전기전자재료학회논문지
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    • 제21권8호
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    • pp.733-737
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    • 2008
  • In this paper, Ni-Co alloy was used to improve thermal stability of Ni Germanide. It was found that uniform germanide is obtained on epitaxial Ge-on-Si substrate by employing Ni-Co alloy. Moreover, neither agglomeration nor penetration is observed during post-germanidation annealing process. The thermal stability of Ni germanide using Ni-Co alloy is improved due to the less agglomeration of Germanide. Therefore, the proposed Ni-Co alloy is promising for highly thermal immune Ni germanide for nano scale Ge-MOSFETs technology.

광기록매체용 Ge-Sb-Te 다층 박막의 광학적 특성 및 열전달 특성 (Optcal and thermal diffusion properties of Ge-Sb-Te multi-layered thin films for optical recording media)

  • 김도형;김상준;김상열;안성혁
    • 한국광학회지
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    • 제12권5호
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    • pp.394-400
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    • 2001
  • 다층 박막에서의 빛의 반사와 흡수 및 열전달 방정식을 수치해석적으로 풀어 광기록매체용 다층 박막의 광학적 특성과 열전달 특성을 알아보고 이 두 특성들을 모두 고려하여 광기록에 적합한 레이저의 출력 및 지속시간, 다층 박막 구조 상수를 제시하였다. 그 결과 레이저는 650 nm 파장을 기준으로 출력 18mW, 지속 시간 60 nm가 적당하였으며 박막 구조 상수는 ZnS-SiO$_2$140nm, Ge-Sb-Te 20 nm, ZnS-SiO$_2$20~30nm, Al-alloy 100~150 nm가 적당하였다.

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Conversion from SIMS depth profiling to compositional depth profiling of multi-layer films

  • Jang, Jong-Shik;Hwang, Hye-Hyen;Kang, Hee-Jae;Kim, Kyung-Joong
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2011년도 제40회 동계학술대회 초록집
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    • pp.347-347
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    • 2011
  • Secondary ion mass spectrometry (SIMS) was fascinated by a quantitative analysis and a depth profiling and it was convinced of a in-depth analysis of multi-layer films. Precision determination of the interfaces of multi-layer films is important for conversion from the original SIMS depth profiling to the compositional depth profiling and the investigation of structure of multi-layer films. However, the determining of the interface between two kinds of species of the SIMS depth profile is distorted from original structure by the several effects due to sputtering with energetic ions. In this study, the feasibility of 50 atomic % definition for the determination of interface between two kinds of species in SIMS depth profiling of multilayer films was investigated by Si/Ge and Ti/Si multi-layer films. The original SIMS depth profiles were converted into compositional depth profiles by the relative sensitivity factors from Si-Ge and Si-Ti alloy reference films. The atomic compositions of Si-Ge and Si-Ti alloy films determined by Rutherford backscattering spectroscopy (RBS).

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