• 한국세라믹학회지
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• 제35권4호
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• pp.333-338
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• 1998

Mechanical properties of polycrystalline{{{{ {Ti }_{3 }{SiC}_{2 } }} were investigated. Hertzian indentation test using a spher-ical indenter was used to study elastic and plastic behavior in{{{{ {Ti }_{3 }{SiC}_{2 } }} A high ratio of hardness to elastic mo-dulus indicated that mechanical properties of{{{{ {Ti }_{3 }{SiC}_{2 } }} are somehow similar to those of metals. Indentation stress-strain curve deviated from an ideal elastic limit indicating exceptional plasticity in this material. De-formation zones were formed below the contact as well as around the contact area. Intragrain slip would ac-count for high plasticity.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.236-236
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• 2009

This paper describes the fabrication and characteristics of Schottky micro hydrogen sensors for high temperatures by using polycrystalline(poly) 3C - SiC thin film grown on Si substrates with thermal oxide layer using APCVD. Pd/poiy 3C-SiC Schottky diodes were made and evaluated by I-V and C-V measurements. Electric current density and barrier height voltage were $2\times10^{-3}\;A/cm^2$ and 0.58 eV, respectively. These devices could operate stably at about $400^{\circ}C$. According to $H_2$ concentrations, their barrier height($\Phi_{Bn}$) were changed 0.587 eV, 0.579 eV, 0.572 eV and 0.569 eV, respectively. the current was increased. Characteristics of implemented sensors have been investigated in terms of sensitivity, linearity of response, response rate and response time. Therefore, from these results, Pd/poly 3C-SiC Schottky devices have very high potential for high temperature chemical sensor applications.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.305-308
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• 2004

We present a novel process for the ultra low temperature (<150$^{\circ}C$) polycrystalline silicon (ULTPS) TFT for the flexible display applications on the plastic substrate. The sequential lateral solidification (SLS) was used for the crystallization of the amorphous silicon film deposited by rf magnetron sputtering, resulting in high mobility polycrystalline silicon (poly-Si) film. The gate dielectric was composed of thin $SiO_2$ formed by plasma oxidation and $Al_2O_3$ deposited by plasma enhanced atomic layer deposition. The breakdown field of gate dielectric on poly-Si film showed above 6.3 MV/cm. Laser activation reduced the source/drain resistance below 200 ${\Omega}$/ㅁ for n layer and 400 ${\Omega}$/ㅁ for p layer. The fabricated ULTPS TFT shows excellent performance with mobilities of 114 $cm^2$/Vs (nMOS) and 42 $cm^2$/Vs (pMOS), on/off current ratios of 4.20${\times}10^6$ (nMOS) and 5.7${\times}10^5$ (PMOS).

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.74-75
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• 2008

This work has suggested corrugation beam as a new structure for mechanical resonators. Micro beam resonators based on 3C-SiC films which have two side corrugations along the length of beams were simulated by finite-element modeling and compared to a flat rectangular beam with the same dimension. With the dimension of $36\times12\times0.5{\mu}m^3$, the flat cantilever has resonant frequency of 746 kHz. Meanwhile, this frequency reaches 1.252 MHz with the corrugated cantilever which has the same dimension with flat type but corrugation width of $6{\mu}m$ and depth of $0.4{\mu}m$. It is expected that mechanical resonators with corrugations will be very helpful for the research of sensing devices with high-resolution, high-performance oscillators and filters in wireless communications as well as measurement in basic physics.

• 센서학회지
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• 제18권2호
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• pp.147-153
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• 2009

A thermal flow sensor has been fabricated and characterized, consisting of a center resistive heater surrounded by two upstream and one downstream temperature sensing resistors. The heater and temperature sensing resistors are fabricated from nitrogen-doped(n-type) polycrystalline silicon carbide(poly-SiC) deposited by LPCVD(low pressure chemical vapor deposition) on LPCVD silicon nitride films on a Si substrate. Cavities were etched into the Si substrate from the front side to create suspended silicon nitride membranes carrying the poly-SiC elements. One upstream sensor is located $50{\mu}m$ from the heater and has a sensitivity of $0.73{\Omega}$/sccm with ${\sim}15\;ms$ rise time in a dynamic range of 1000 sccm. N-type poly-SiC has a linear negative temperature coefficient and a TCR(temperature coefficient of resistance) of $-1.24{\times}10^{-3}/^{\circ}C$ from room temperature to $100^{\circ}C$.

• 한국결정성장학회지
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• 제3권1호
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• pp.59-65
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• 1993

저항가열식 고진공증착기를 이용하여 압력센서로 사용될 수 있는 boron이 첨가된 다결정 silicon 박막이 제조되었다. 다결정 silicon 박막은 여러온도에서 quartz 기판위에 증착되었으며, boron은 BN 웨이퍼를 사용하여 확산로에서 doping하였다. $500^{\circ}C$의 기판온도에서 증착된 silicon 박막은 비정질이었으며, $600^{\circ}C$에서 결정을 보이기 시작하였고, $700^{\circ}C$에서 다결정이 되었다. $900^{\circ}C$에서 10분동안 boron을 dopion한 후, 박막의 비저항은 $0.1{\Omega}cm~1.5{\Omega}cm$의 범위에 있었으며, boron 밀도(농도)는 $9.4$\times$10^{15}~2.1$\times${10}^{17}cm^{-3}$이었고, 입자의 크기는 $107{\AA}~191{\AA}$이었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.235-235
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• 2009

This paper describes the influence of a polycrystalline (poly) 3C-SiC buffer layer on the surface acoustic wave (SAW) properties of poly aluminum nitride (AlN) thin films by comparing the center frequency, insertion loss, the electromechanical coupling coefficient ($k^2$), andthetemperaturecoefficientoffrequency(TCF) of an IDT/AlN/3C-SiC structure with those of an IDT/AlN/Si structure, The poly-AlN thin films with an (0002)-preferred orientation were deposited on a silicon (Si) substrate using a pulsed reactive magnetron sputtering system. Results show that the insertion loss (21.92 dB) and TCF (-18 ppm/$^{\circ}C$) of the IDT/AlN/3C-SiC structure were improved by a closely matched coefficient of thermal expansion (CTE) and small lattice mismatch (1 %) between the AlN and 3C-SiC. However, a drawback is that the $k^2(0.79%)$ and SAW velocity(5020m/s) of the AlN/3C-SiC SAW device were reduced by appearing in some non-(0002)AlN planes such as the (10 $\bar{1}$ 2) and (10 $\bar{1}$ 3) AlN planes in the AlN/SiC film. Although disadvantages were shown to exist, the use of the AlN/3C-SiC structure for SAW applications at high temperatures is possible. The characteristics of the AlN thin films were also evaluated using FT-IR spectra, XRD, and AFM images.

• 센서학회지
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• 제19권3호
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• pp.197-201
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• 2010

This paper describes the fabrication and characteristics of a NO sensor using ZnO thin film integrated 3C-SiC micro heater based on polycrystalline 3C-SiC thin film of operation in harsh environments. The sensitivity, response time, and operating properties in high temperature and voltages of NO sensors based SiC MEMS are measured and analyzed. The sensitivity of device with pure ZnO thin film at the heater operating power of 13.5 mW ($300^{\circ}C$) is 0.875 in NO gas concentration of 0.046 ppm. In the case of Pt doping, the sensitivity of at power consumption of 5.9 mW ($250^{\circ}C$) was 1.92 at same gas flow rate. The ZnO with doped Pt was showed higher sensitivity, lower working temperature and faster adsorption characteristics to NO gas than pure ZnO thin film. The NO gas sensor integrated SiC micro heater is more strength than others in high voltage and temperature environments.

• 대한금속재료학회지
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• 제46권3호
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• pp.159-168
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• 2008

Thermally-evaporated 10 nm-Ni/1 nm-Ru/(30 nm or 70 nm-poly)Si structures were fabricated in order to investigate the thermal stability of Ru-inserted nickel monosilicide. The silicide samples underwent rapid thermal anne aling at $300{\sim}1,100^{\circ}C$ for 40 seconds. Silicides suitable for the salicide process were formed on the top of the single crystal and polycrystalline silicon substrates mimicking actives and gates. The sheet resistance was measured using a four-point probe. High resolution X-ray diffraction and Auger depth profiling were used for phase and chemical composition analysis, respectively. Transmission electron microscope and scanning probe microscope(SPM) were used to determine the cross-sectional structure and surface roughness. The silicide, which formed on single crystal silicon and 30 nm polysilicon substrate, could defer the transformation of $Ni_2Si $i and $NiSi_2 $, and was stable at temperatures up to $1,100^{\circ}C$ and $1,100^{\circ}C$, respectively. Regarding microstructure, the nano-size NiSi preferred phase was observed on single crystalline Si substrate, and agglomerate phase was shown on 30 nm-thick polycrystalline Si substrate, respectively. The silicide, formed on 70 nm polysilicon substrate, showed high resistance at temperatures >$700^{\circ}C$ caused by mixed microstructure. Through SPM analysis, we confirmed that the surface roughness increased abruptly on single crystal Si substrate while not changed on polycrystalline substrate. The Ru-inserted nickel monosilicide could maintain a low resistance in wide temperature range and is considered suitable for the nano-thick silicide process.

• 한국세라믹학회지
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• 제34권5호
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• pp.483-490
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• 1997

Al2O3/metal composites were fabricated by oxidation and reaction of molten Al-alloy into two types of commercial Al2O3-SiO2 fibrous insulation board. The growth rate, composition and microstructure of these materials were described. An AlZnMg(7075) alloy was selected as a parent alloy. Mixed polycrystalline fiber and glass phase fiber were used as a filler. The growth surface of an alloy was covered with and without SiO2. SiO2 powder was employed as a surface dopant to aid initial oxidation of Al-alloy. Al-alloy, SiO2, fiber block and growth inhibitor CaSiO3 were packed sequentially in a alumina crucible and oxidized in air at temperature range 90$0^{\circ}C$ to 120$0^{\circ}C$. The growth rate of composite layer was calculated by measuring the mass increasement(g) per unit surface($\textrm{cm}^2$). XRD and optical microscope were used to investigate the composition and phase of composites. The composite grown at 120$0^{\circ}C$ and with SiO2 dopant showed rapid growth rate. The growth behavior differed a little depending on the types of fiber used. The composites consist of $\alpha$-Al2O3, Al, Si and pore. The composite grown at 100$0^{\circ}C$ exhibited better microstructure compared to that grown at 120$0^{\circ}C$.