• Title/Summary/Keyword: polycrystalline Si

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Ohmic contact formation of polycrystalline 3C-SiC for high-temperature MEMS applications (초고온 MEMS용 다결정 3C-SiC의 Ohmic Contact 형성)

  • Ohn, Chang-Min;Chung, Gwiy-Sang
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2006.06a
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    • pp.406-407
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    • 2006
  • This paper describes the ohmic contact formation between a TiW film as a contact material deposied by RF magnetron sputter and polycrystalline 3C-SiC films deposied on thermally grown Si wafers. The specific contact resistance (${\rho}_c$) of the TiW contact was measured by using the C-TLM. The contact phase and interfacial reaction between TiW and 3C-SiC at high-temperature were also analyzed by XRD and SEM. All of the samples didn't show cracks of the TiW film and any interfacial reaction after annealing. Especially, when the sample was annealed at $800^{\circ}$ for 30min., the lowest contact resistivity of $2.90{\times}10^{-5}{\Omega}cm^2$ was obtained due to the improved interfacial adhesion.

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Excimer-Laser Crystallization for Low-Temperature Polycrystalline Si TFTs

  • Kim, Hyun-Jae
    • 한국정보디스플레이학회:학술대회논문집
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    • 2000.01a
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    • pp.151-152
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    • 2000
  • For excimer laser crystallization (ELC), energy density, number of pulses, beam uniformity, and condition of initial amorphous Si (a-Si) films are significant factors contributing the final microstructure and the performance of low-temperature polycrystalline Si TFTs. The process and equipment have been achieved a significant improvement, but still, environmental factors associated with initial amorphous Si (a-Si) films and process conditions need to be optimized.

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Electrical characteristics of polycrystalline 3C-SiC thin film diodes (다결정 3C-SiC 박막 다이오드의 전기적 특성)

  • Chung, Gwiy-Sang;Ahn, Jeong-Hak
    • Journal of Sensor Science and Technology
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    • v.16 no.4
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    • pp.259-262
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    • 2007
  • This paper describes the electrical characteristics of polycrystalline (poly) 3C-SiC thin film diodes, in which poly 3C-SiC thin films on n-type and p-type Si wafers, respectively, were deposited by APCVD using HMDS, $H_{2}$, and Ar gas at $1150^{\circ}C$ for 3 hr. The schottky diode with Au/poly 3C-SiC/Si (n-type) structure was fabricated. Its threshold voltage ($V_{bi}$), breakdown voltage, thickness of depletion layer, and doping concentration ($N_{D}$) value were measured as 0.84 V, over 140 V, 61 nm, and $2.7{\times}10^{19}cm^{-3}$, respectively. Moreover, for the good ohmic contact, Al/poly 3C-SiC/Si (n-type) structure was annealed at 300, 400, and $500^{\circ}C$, respectively for 30 min under the vacuum condition of $5.0{\times}10^{-6}$ Torr. Finally, the p-n junction diodes fabricated on the poly 3C-Si/Si (p-type) were obtained like characteristics of single 3CSiC p-n junction diode. Therefore, poly 3C-SiC thin film diodes will be suitable for microsensors in conjunction with Si fabrication technology.

Fabrication of polycrystalline 3C-SiC thin film diodes (다결정 3C-SiC 박막 다이오드의 제작)

  • Ahn, Jeong-Hak;Chung, Gwiy-Sang
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2007.06a
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    • pp.348-349
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    • 2007
  • This paper describes the electrical characteristics of polycrystalline (poly) 3C-SiC thin film diodes, in which poly 3C-SiC thin films on n-type and p-type Si wafers, respectively, were deposited by APCVD using HMDS, Hz, and Ar gas at $1180^{\circ}C$ for 3 hr. The schottky diode with Au/poly 3C-SiC/Si(n-type) structure was fabricated. Its threshold voltage ($V_d$), breakdown voltage, thickness of depletion layer, and doping concentration ($N_D$) values were measured as 0.84 V, over 140 V, 61nm, and $2.7\;{\times}\;10^{19}\;cm^3$, respectively. The p-n junction diodes fabricated on the poly 3C-SiC/Si(p-type) were obtained like characteristics of single 3C-SiC p-n junction diodes. Therefore, poly 3C-SiC thin film diodes will be suitable microsensors in conjunction with Si fabrication technology.

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Fabrication of polycrystalline 3C-SiC micro pressure sensors for hightemperature applications (초고온용 다결정 3C-SiC 마이크로 압력센서의 제작)

  • Chung, Gwiy-Sang
    • Journal of Sensor Science and Technology
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    • v.19 no.1
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    • pp.31-35
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    • 2010
  • High temperature micro pressure sensors were fabricated by using polycrystalline 3C-SiC piezoresistors grown on oxidized SOI substrates by APCVD. These have been made by bulk micromachining under $1{\times}1mm^2$ diaphragm and Si membrane thickness of $20{\mu}m$. The pressure sensitivity of implemented pressure sensors was 0.1 mV/$V{\cdot}bar$. The nonlinearity and the hysteresis of sensors were ${\pm}0.44%{\cdot}FS$ and $0.61%{\cdot}FS$. In the temperature range of $25^{\circ}C{\sim}400^{\circ}C$ with 5 bar FS, TCS (temperature coefficient of sensitivity), TCR (temperature coefficient of resistance), and TCGF (temperature coefficient of gauge factor) of the sensor were -1867 ppm/$^{\circ}C$, -792 ppm/$^{\circ}C$, and -1042 ppm/$^{\circ}C$, respectively.

Characteristics of polycrystalline 3C-SiC micro pressure sensors for high temperature applications (초고온용 다결정 3C-SiC 마이크로 압력센서의 특성)

  • Thien, Duong Xuan;Chung, Gwiy-Sang
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.06a
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    • pp.387-388
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    • 2008
  • High temperature micro pressure sensors were fabricated by polycrystalline (poly) 3C-SiC piezoresistors formed by oxidized SOI substrates with APCVD. These have been designed by bulk micromachining below $1{\times}1mm^2$ diaphragm and Si membrane $20{\mu}m$ thick. The pressure sensitivity of fabricated pressure sensor was 0.1 mV/Vbar. The non-linearity of sensor was ${\pm}0.44%$ FS and the hysteresis was 0.61% FS.TCS of pressure sensor was -1867 ppm/$^{\circ}C$, its TCR was -792 ppm/$^{\circ}C$, and TCGF to 5 bar was -1042 ppm/$^{\circ}C$ from 25 to $400^{\circ}C$.

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Influence of surface roughness of ZnO layer on the growth of polycrystalline Si layer via aluminum-induced layer exchange process

  • Choi, Sung-Kuk;Chang, Won-Beom;Jung, Soo-Hoon;Hara, Kosuke;Watanabe, Haruna;Usami, Noritaka;Chang, Ji-Ho
    • Journal of Advanced Marine Engineering and Technology
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    • v.40 no.8
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    • pp.692-697
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    • 2016
  • This study investigated the effect of surface roughness of zinc oxide (ZnO) layer on the growth of polycrystalline Si layer via an Al-induced layer exchange process. It was found that the growth rate, grain size, crystallization fraction, and preferential orientation of the polycrystalline Si layer were strongly influenced by the surface roughness of the underlying ZnO layer. As the roughness of the ZnO surface increased, a higher growth rate (~40 min) and preferential Si (100) orientation were obtained because of the spatial concentration fluctuations in the Al-Si alloy, induced by the surface roughness of the underlying ZnO layer.

Fabrication of polycrystalline 3C-SiC diode for harsh environment micro chemical sensors and their characteristics (극한 환경 마이크로 화학센서용 다결정 3C-SiC 다이오드 제작과 그 특성)

  • Shim, Jae-Cheol;Chung, Gwiy-Sang
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.06a
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    • pp.195-196
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    • 2009
  • This paper describes the fabrication and characteristics of polycrystalline 3C-SiC thin film diodes for extreme environment applications, in which the this thin film was deposited onto oxidized Si wafers by APCVD using HMDS In this work, the optimized growth temperature and HMDS flow rate were $1,100^{\circ}C$ and 8sccm, respectively. A Schottky diode with a Au, Al/poly 3C-SiC/$SiO_2$/Si(n-type) structure was fabricated and its threshold voltage ($V_d$), breakdown voltage, thickness of depletion layer, and doping concentration ($N_D$) values were measured as 0.84V, over 140V, 61nm, and $2.7{\times}10^{19}cm^2$, respectively. To produce good ohmic contact, Al/3C-SiC were annealed at 300, 400, and $500^{\circ}C$ for 30min under a vacuum of $5.0{\times}10^{-6}$Torr. The obtained p-n junction diode fabricated by poly 3C-SiC had similar characteristics to a single 3C-SiC p-n junction diode.

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Growth of polycrystalline 3C-SiC thin films for M/NEMS applications by CVD (CVD에 의한 M/NEMS용 다결정 3C-SiC 박막 성장)

  • Chung, Gwiy-Sang;Kim, Kang-San;Jeong, Jun-Ho
    • Journal of Sensor Science and Technology
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    • v.16 no.2
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    • pp.85-90
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    • 2007
  • This paper presents the growth conditions and characteristics of polycrystalline 3C-SiC (silicon carbide) thin films for M/NEMS applications related to harsh environments. The growth of the 3C-SiC thin film on the oxided Si wafers was carried out by APCVD using HMDS (hexamethyildisilane: $Si_{2}(CH_{3})_{6})$ precursor. Each samples were analyzed by XRD (X-ray diffraction), FT-IR (fourier transformation infrared spectroscopy), RHEED (reflection high energy electron diffraction), GDS (glow discharge spectrometer), XPS (X-ray photoelectron spectroscopy), SEM (scanning electron microscope) and TEM (tunneling electro microscope). Moreover, the electrical properties of the grown 3C-SiC thin film were evaluated by Hall effect. From these results, the grown 3C-SiC thin film is very good crystalline quality, surface like mirror and low defect. Therefore, the 3C-SiC thin film is suitable for extreme environment, Bio and RF M/NEMS applications in conjunction with Si fabrication technology.

Raman Scattering Characteristics of Polycrystalline 3C-SiC Thin Films deposited on AlN Buffer Layer (AlN 버퍼층위에 증착된 다결정 3C-SiC 박막의 라만 산란 특성)

  • Chung, Gwiy-Sang;Kim, Kang-San
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.21 no.6
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    • pp.493-498
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    • 2008
  • This Paper describes the Raman scattering characteristics of polycrystalline (Poly) 3C-SiC thin films, in which they were deposited on AlN buffer layer by APCVD using hexamethyldisilane (MHDS) and carrier gases (Ar+$H_2$). When the Raman spectra of SiC films deposited on the AlN layer of before and after annealing were worked according to growth temperature, D and G bands of graphite were measured. It can be explained that poly 3C-SiC films admixe with nanoparticle graphite and its C/Si rate is higher than ($C/Si\;{\approx}\;3$) that of the conventional SiC, which has no D and G bands related to graphite. From the Raman shifts of 3C-SiC films deposited at $1180^{\circ}C$ on the AlN layer of after annealing, the biaxial stress of poly 3C-SiC films was obtained as 896 MPa.