• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.18-19
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• 2008

Polycrystalline(poly) 3C-SiC film is a promising structural material for M/NEMS used in harsh environments, bio and fields. In order to realize poly 3C-SiC based M/NEMS devices, the electrical properties of poly 3C-SiC film have to be optimized. The n-type poly 3C-SiC thin film is deposited by APCVD using HMDS$(Si_2(CH_3)_6)$ as single precursor and are in-situ doped using N2. Resistivity values as low as 0.014 $\Omega$cm were achieved. The carrier concentration increased with doping from $3.0819\times10^{17}$ to $2.2994\times10^{19}cm^{-3}$ and electronicmobility increased from 2.433 to 29.299 $cm^2/V{\cdot}s$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.131-131
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• 2009

This paper describes the fabrication and characteristics of polycrystalline (poly) 3C-SiC microresonators with $3{\times}10^{17}{\sim}1{\times}10^{19}cm^{-3}$ in-situ N-doping concentrations. In this work, the crystallinity, carrier concentration and surface morphology of the grown thin films were evaluated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The 1.2 ${\mu}m$ thick cantilvers and the 0.4 ${\mu}m$ thick doubly-clamped beam microresonators with various lengths were implemented using in-situ doping poly 3C-SiC thin films. The characteristics of the poly 3C-SiC microresonators were evaluated using quartz and a laser vibrometer under vacuum at room temperature. The resonant frequencies of the SiC microresonators decreased with doping concentrations owing to the reduction of the Young's modulus of the poly 3C-SiC thin films. It was confirmed that the resonant frequencies of the poly 3C-SiC microresonators are controllable by adjusting the doping concentrations.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.24 no.1
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• pp.9-16
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• 2011

An approach to understand the phase distribution in a multi-phase polycrystalline material is important since it can affect material properties and mechanical behaviors. A proper method is needed to describe the phase distribution. For this purpose, contiguity and probability functions(two-point correlation and lineal-path functions) are investigated for representing the phase distributions of microstructures. The mechanical behaviors are evaluated using the finite element method. The characteristics of probability functions and mechanical reponses of virtual samples are represented. It is confirmed that the topology of phase clustering affects the mechanical behavior of materials and that the strength is reduced as the clustering size increases.

• 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.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.5
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• pp.344-349
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• 2020

Modern thin film deposition processes require high deposition rates, low costs, and high-quality films. Atmospheric pressure plasma-enhanced chemical vapor deposition (AP-PECVD) meets these requirements. AP-PECVD causes little damage on thin film deposition surfaces compared to conventional PECVD. Moreover, a higher deposition rate is expected due to the surface heating effect of atomic hydrogens in AP-PECVD. In this study, polycrystalline silicon thin film was deposited at a low temperature of 100℃ and then AP-PECVD experiments were performed with various plasma powers and hydrogen gas flow rates. A deposition rate of 15.2 nm/s was obtained at the VHF power of 400 W. In addition, a metal foam showerhead was employed for uniform gas supply, which provided a significant improvement in the thickness uniformity.

• 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.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.11a
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• pp.126-130
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• 1995

$CdS_{1-x}Te_{1-x}$ polycrystalline thin films were fabricated from CdS and CdTe powder by co-evaporation method at $10^{-6}$ Torr. The Optimum evaporation condition was substrate temperature $T_{s}$=$150^{\circ}C$, evaporation time t=30 min. XRD spectrums indicated that the crystal structure chanced from zinc blonde (x$\leq$0.22) to wurtzite (x$\geq$0.96) through mixed structure (0.22$\leq$0.74) as composition value x increase to CdS. Conductive type was n-type by hot point probe method. van der Pauw method was not applicable for x<0,5 due to high hall voltages, Electrical resistivity and Hall carrier mobility were decreased as x increase, while Hall carrier concentration was increased. The optical bandgap of $CdS_{1-x}Te_{1-x}$ polycrystalline thin films measure d at R.T. had quardratic form and the bowing parameter was fitted as 1.98eV for theoretical value of 2.0eV. I-V characteristics of In/CdTe/$CdS_{x}Te_{1-x}$Au Schottky diodes showed that CdS-rich one had better forward characteristics than CdTe-rich one.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.04b
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• pp.69-72
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• 2002

We establish a visible light emission from porous polycrystalline silicon nano structure(PPNS). The PPNS layer are formed on heavily doped n-type Si substrate. 2um thickness of undoped polycrystalline silicon deposited using LPCVD (Low Pressure Chemical Vapor Deposition) anodized in a HF: ethanol(=1:1) as functions of anodizing conditions. And then a PPNS layer thermally oxidized for 1 hr at $900^{\circ}C$. Subsequently, thin metal Au as a top electrode deposited onto the PPNS surface by E-beam evaporator and, in order to establish ohmic contact, an thermally evaporated Al was deposited on the back side of a Si-substrate. When the top electrode biased at +6V, the electron emission observed in a PPNS which caused by field-induces electron emission through the top metal. Among the PPNSs as functions of anodization conditions, the PPNS anodized at a current density of $10mA/cm^{2}$ for 20 sec has a lower turn-on voltage and a higher emission current. Furthermore, the behavior of electron emission is uniformly maintained.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.3
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• pp.234-239
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• 2007

This paper describes the TiW ohmic contact characteristics under the surface treatment of the polycrystalline 3C-SiC thin film grown on $SiO_2/Si(100)$ wafers by APCVD. The poly 3C-SiC surface was polished by using CMP(chemical mechanical polishing) process and then oxidized by wet-oxidation process, and finally removed SiC oxide layers. A TiW thin film as a metalization process was deposited on the surface treated poly 3C-SiC layer and was annealed through a RTA(rapid thermal annealing) process. TiW/poly 3C-SiC was investigated to get mechanical, physical, and electrical characteristics using SEM, XRD, XPS, AFM, optical microscope, I-V characteristic, and four-point probe, respectively. Contact resistivity of the surface treated 3C-SiC was measured as the lowest $1.2{\times}10^{-5}{\Omega}cm^2$ at $900^{\circ}C$ for 45 sec. Therefore, the surface treatments of poly 3C-SiC are necessary to get better contact resistance for extreme environment MEMS applications.

• 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.