• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.69-70
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• 2008

Micro resonators have been actively investigated for bio/chemical sensors and RF M/NEMS devices. Among various materials, SiC is a very promising material for micro/nano resonators since the ratio of its Young's modulus, E, to mass density, $\rho$, is significantly higher than other semiconductor materials, such as, Si and GaAs. Polycrystalline 3C-SiC cantilever with different lengths were fabricated using a surface micromachining technique. Polycrystalline 3C-SiC micro resonators were actuated by piezoelectric element and its fundamental resonance was measured by a laser vibrometer in air and vacuum at room temperature, respectively. For the cantilever with $100{\mu}m$ length, $10{\mu}m$width and $1.3{\mu}m$ thickness, the fundamental frequency appeared at 147.2 kHz.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1472-1475
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• 2009

The microfluidics channel were fabricated using thermal roll-imprinting process on plastic substrates. As rollimprinting surface is heated directly at $100^{\circ}C$ and printing process proceed 380/400 kgf pressure, we fabricated microfluidic patterns separated line of $40.04{\mu}m$, serpentine line of $113.89{\mu}m$ and depth of imprint pattern is $15.35{\mu}m$, it means to get fine pattern has more than 70% imprint rate in designed mask.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.8
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• pp.152-156
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• 2004

A new tool of surface patterning technique for general purpose lithography was developed based on shadow mask method. This paper describes the fabrication of a new type of miniaturized shadow mask. The shadow mask is fabricated by photolithography and etching of 100-mm full wafer. The fabricated shadow mask has over 388 membranes with apertures of micrometer length scale ranging from 1${\mu}{\textrm}{m}$ to 100s ${\mu}{\textrm}{m}$ made on each 2mm${\times}$2mm large low stress silicon nitride membrane. It allows micro scale patterns to be directly deposited on substrate surface through apertures of the membrane. This shadow mask method has much wider choice of deposit materials, and can be applied to wider class of surfaces including chemical functional layer, MEMS/NEMS surfaces, and biosensors.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.252-252
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• 2008

The microhotplates consisting of a Pt-ased heating element on AlN/poly 3C-SiC layers were fabricated. The microhotplate has a $600{\mu}m{\times}600{\mu}m$ square shaped membrane which made of $1{\mu}m$ thick ploycrystalline 3C-SiC suspended by four legs. 3C-SiC is known for excellent chemical durability, mechanical strength and sustaining of high temperature. The membrane is fabricated by surface micromachining using oxidized Si sacrificial layer. The Pt thin film is used for heating material and resist temperature sensor. The fabrication methodology allows intergration of an array of heating material and resist temperature detector. For reasons of a short response time and a high sensitivity a uniform temperature profile is desired. The dissipation of microhotplate was examined by a IR thermoviewer and the power consumption was measured. Measured and simulated results are compared and analyzed. Thermal characterization of the microhotplates shows that significant reduction in power consumption was achieved using suspended structure.

• Journal of Sensor Science and Technology
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• v.17 no.5
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• pp.325-328
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• 2008

This paper describes the electrical properties of poly (polycrystalline) 3C-SiC thin films with different nitrogen doping concentrations. In-situ doped poly 3C-SiC thin films were deposited by APCVD at $1200^{\circ}C$ using HMDS (hexamethyildisilane: $Si_2(CH_3)_6)$) as Si and C precursor, and $0{\sim}100$ sccm $N_2$ as the dopant source gas. The peak of SiC is appeared in poly 3C-SiC thin films grown on $SiO_2/Si$ substrates in XRD(X-ray diffraction) and FT-IR(Fourier transform infrared spectroscopy) analyses. The resistivity of poly 3C-SiC thin films decreased from $8.35{\Omega}{\cdot}cm$ with $N_2$ of 0 sccm to $0.014{\Omega}{\cdot}cm$ with 100 sccm. The carrier concentration of poly 3C-SiC films increased with doping from $3.0819{\times}10^{17}$ to $2.2994{\times}10^{19}cm^{-3}$ and their electronic mobilities increased from 2.433 to $29.299cm^2/V{\cdot}S$, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.237-237
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• 2009

Zinc oxide (ZnO) thin film was deposited on Si substrates using polycrystalline (poly) 3C-SiC buffer layer, in which the ZnO film was grown by sol-gel method. Physical characteristics of the grown ZnO film was investigated experimentally by means of SEM, XRD, FT-IR (Furier Transform-Infrared spectrum), and AFM. XRD pattern was proved that the grown ZnO film on 3C-SiC layers had highly (002) orientation with low FWHM (Full width of half maxium). These results showed that ZnO thin film grown on 3C-SiC buffer layers can be used for various piezoelectric fields and M/NEMS applications.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2007.06a
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• pp.183-187
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• 2007

The magnetron reactive ion etching (RIE) characteristics of polycrystalline (poly) 3C-SiC grown on $SiO_2$/Si substrate by APCVD were investigated. Poly 3C-SiC was etched by $CHF_3$ gas, which can form a polymer as a function of side wall protective layers, with additive $O_2$ and Ar gases. Especially, it was performed in magnetron RIE, which can etch SiC at lower ion energy than a commercial RIE system. Stable etching was achieved at 70 W and the poly 3C-SiC was undamaged. The etch rate could be controlled from $20\;{\AA}/min$ to $400\;{\AA}/min$ by the manipulation of gas flow rates, chamber pressure, RF power, and electrode gap. The best vertical structure was improved by the addition of 40 % $O_2$ and 16 % Ar with the $CHF_3$ reactive gas. Therefore, poly 3C-SiC etched by magnetron RIE can expect to be applied to M/NEMS applications.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.346-347
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• 2007

Aluminum nitride (AlN) thin films were deposited on Polycrystalline (poly) 3C-SiC buffer layers using pulsed reactive magnetron sputtering. Characteristics of AlN films were investigated experimentally by means of FE-SEM, X-ray diffraction, and FT-IR, respectively. As a result, highly (002) oriented AlN thin films with almost free residual stress were achieved using 3C-SiC buffer layers. Therefore, AlN thin films grown on 3C-SiC buffer layers can be used for various piezoelectric fields and M/NEMS applications.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.134-135
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• 2007

Growth of cubic SiC has been carried out on oxided Si substrate using atmospheric pressure chemical vapor deposition (APCVD). Hexamethyldisilane (HMDS) was used as the single precursor and nonflammable mixture of Ar and $H_2$ was used as carrier gas. Epitaxial growth had performed depositions under the various $H_2$ conditions which were adjusted from 0 to 100 seem. The effects of $H_2$ was characterized by surface roughness, thickness uniformity, films quality and elastic modulus. Thickness uniformity and films quality were performed by SEM. Surface roughness and elastic modulus were investigated by AFM and Nano-indentor, respectively. According to the $H_2$ flow rate, Poly 3C-SiC thin film quality was improved not only physical but also mechanical properties.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.357-358
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• 2007

Raman spectra of poly (polycrystalline) 3C-SiC thin films, which were deposited on the oxidized Si substrate by APCVD, have been measured. They were used to study the mechanical characteristics of poly 3C-SiC grown in various temperatures. TO and LO modes of 2.0 m poly 3C-SiC grown at 1180 C occurred at 794.4 and $965.7\;cm^{-1}$. Their FWHMs (full width half maximum) were used to investigate the stress and the disorder of 3C-SiC. The broad FWHM can explain that the crystallinity of 3C-SiC grown at 1180 C becomes poly crystalline instead of the disordered crystal. The ratio of intensity $I_{(LO)}/I_{(TO)}$ 1.0 means that the crystal defect of 3C-SiC/$SiO_2$/Si is small. The biaxial stress of poly 3C-SiC was obtained as 428 MPa. In the interface of 3C-SiC/$SiO_2$, the phonon mode of C-O bonding appeared at $1122.6\;cm^{-1}$. The phonon modes related to D and G bands of C-C bonding were measured at 1355.8 and $1596.8\;cm^{-1}$ respectively.