3C-SiC Micro Research Articles

SiC 마이크로 히터가 내장된 극한 환경용 NO 센서의 제작과 특성

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 (<TEX>$300^{\circ}C$</TEX>) 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 (<TEX>$250^{\circ}C$</TEX>) 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.

Effect of &lt;i&gt;In Situ&lt;/i&gt; Doped Nitrogen Concentrations on the Characteristics of Poly 3C-SiC Micro Resonators

This paper describes the characteristics of polycrystalline 3C-SiC micro resonators with 3 ×1017 - 1×1019 cm-3 in-situ N-doping concentrations. In this work, the 1.2 μm thick cantilevers and the 0.4 μm thick doubly-clamped beam micro resonators with various lengths were implemented using in-situ doping poly 3C-SiC thin films. The characteristics of the poly 3C-SiC micro resonators were evaluated using quartz actuator and optical read-out vibrometer under vacuum conditions at room temperature. The resonant frequencies of the SiC micro resonators 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 micro- resonators are controllable by adjusting the doping concentrations.

Fabrication and Characteristics of Micro Heaters Based on Polycrystalline 3C-SiC for High Temperature and Voltage

This paper describes fabrication and properties of polycrystalline 3C-SiC micro heaters built on AlN(0.1 μm)/3C-SiC(1.0 μm) suspended membranes using surface micromachining technology. 3C-SiC and AlN semiconductors which have a large energy band gap and very low lattice mismatch were used as sensors in harsh environment micro electromechanical system (MEMS) applications in this work. The 3C-SiC thin film was simultaneously used as a resistance of temperature detector (RTD) and micro heater for detecting heated temperature correctly. The thermal coefficient of resistance (TCR) of the implemented 3C-SiC RTD is about -5200 ppm/°C in the temperature range from 25°C to 50°C and -1040 ppm/°C at 500°C. The 3C-SiC micro heater generates about 500°C of heat at 10.3 mW. Moreover, 3C-SiC micro heaters stand at higher applied voltages than case of Pt micro heaters.

3C-SiC 마이크로 히터의 제작과 그 특성

This paper describes the characteristics of a poly 3C-SiC micro heater which was fabricated on AlN(0.1 <TEX>$\mu$</TEX>m)/3C-SiC(1.0 <TEX>$\mu$</TEX>m) suspended membranes by surface micro-machining technology. The 3C-SiC and AlN thin films which have wide energy band gap and very low lattice mismatch were used sensors for high temperature and voltage environments. The 3C-SiC thin film was used as micro heaters and temperature sensor materials simultaneously. The implemented 3CSiC RTD(resistance of temperature detector) and the power consumption of micro heaters were measured and calculated. The TCR(thermal coefficient of the resistance) of 3C-SiC RTD is about -5200 ppm/<TEX>$^{\circ}C$</TEX> within a temperature range from 25 <TEX>$^{\circ}C$</TEX> to 50 <TEX>$^{\circ}C$</TEX> and -1040 ppm/<TEX>$^{\circ}C$</TEX> at 500 <TEX>$^{\circ}C$</TEX>. The micro heater generates the heat about 500 <TEX>$^{\circ}C$</TEX> at 10.3 mW. Moreover, durability of 3C-SiC micro heaters in high voltages is better than Pt micro heaters. A thermal distribution measured and simulated by IR thermovision and COMSOL is uniform on the membrane surface.

도핑농도에 따른 다결정 3C-SiC 마이크로 공진기의 특성

This paper describes the characteristics of poly 3C-SiC micro resonators with <TEX>$3{\times}10^{17}{\sim}1{\times}10^{19}cm^{-3}$</TEX> doping concentrations. The 1.2 <TEX>${\mu}m$</TEX> thick cantilever and the 0.4 <TEX>${\mu}m$</TEX> thick doubly clamped beam resonators with different lengths were fabricated using poly 3C-SiC thin films. The characteristics of poly 3C-SiC micro resonators were evaluated by quartz and a laser vibrometer in vacuum at room temperature. The resonant frequencies of micro resonators decreased with doping concentrations owing to reduction in the Young's modulus of poly 3C-SiC thin films. It was confirmed that the resonant frequencies of poly 3C-SiC resonators are controllable by doping concentrations. Therefore, poly 3C-SiC resonators could be applied to MEMS devices and bio/chemical sensor applications.

다결정 3C-SiC 마이크로 공진기의 온도특성

This paper describes the temperature characteristics of polycrystalline 3C-SiC micro resonators. The <TEX>$1.2{\mu}m$</TEX> and <TEX>$0.4{\mu}m$</TEX> thick polycrystalline 3C-SiC cantilever and doubly clamped beam resonators with <TEX>$60{\sim}100{\mu}m$</TEX> lengths were fabricated using a surface micromachining technique. Polycrystalline 3C-SiC micro resonators were actuated by piezoelectric element and their fundamental resonance was measured by a laser vibrometer in vacuum at temperature range of <TEX>$25{\sim}200^{\circ}C$</TEX>. The TCF(Temperature Coefficient of Frequency) of 60, 80 and 100 On long cantilever resonators were -9.79, -7.72 and -8.0 ppm/<TEX>$^{\circ}C$</TEX>. On the other hand, TCF of 60, 80 and <TEX>$100{\mu}m$</TEX> long doubly clamped beam resonators were -15.74, -12.55 and -8.35 ppm/<TEX>$^{\circ}C$</TEX>. Therefore, polycrystalline 3C-SiC resonators are suitable with RF MEMS devices and bio/chemical sensor applications in harsh environments.

양단이 고정된 빔형 다결정 3C-SiC 마이크로 공진기의 제작과 그 특성

This paper describes the characteristics of polycrystalline 3C-SiC doubly clamped beam micro resonators. The polycrystalline 3C-SiC doubly clamped beam resonators with <TEX>$60{\sim}100{\mu}m$</TEX> lengths, <TEX>$10{\mu}m$</TEX> width, and <TEX>$0.4{\mu}m$</TEX> thickness were fabricated using a surface micromachining technique. Polycrystalline 3C-SiC micro resonators were actuated by piezoelectric element and their fundamental resonant frequency was measured by a laser vibrometer in vacuum at room temperature. For the <TEX>$60{\sim}100{\mu}m$</TEX> long cantilevers, the fundamental frequency appeared at <TEX>$373.4{\sim}908.1\;kHz$</TEX>. The resonant frequencies of doubly clamped beam with lengths were higher than simulated results because of tensile stress. Therefore, polycrystalline 3C-SiC doubly clamped beam micro resonators are suitable for RF MEMS devices and bio/chemical sensor applications.

다결정 SiC 마이크로 공진기의 제작과 그 특성

This paper describes the resonant characteristics of polycrystalline SiC micro resonators. The thick polycrystalline 3C-SiC cantilevers with different lengths were fabricated using a surface micromachining technique. Polycrystalline 3C-SiC micro resonators were actuated by piezoelectric element and their fundamental resonance was measured by a laser vibrometer in vacuum at room temperature. For the long cantilevers, the fundamental frequency appeared at . The and long cantilevers have second mode resonant frequency at 857.5.kHz and 1.14.MHz, respectively. Therefore, polycrystalline 3C-SiC resonators are suitable for RF MEMS devices and bio/chemical sensor applications.

Design of Polycrystalline 3C-SiC Micro Beam Resonators with Corrugation

On the purpose of increasing resonant frequency without sacrificing quality factor as well as much decreasing dimensions, corrugated micro beam resonator based on polycrystalline 3C-SiC films is the applicable solution. In this work, appropriate corrugated structure is suggested to increase resonant frequency of resonators. Micro beam resonators based on 3C-SiC films which have a two-side corrugation along the length of beams were simulated by finite element method and compared to a same-size flat rectangular. With the dimension of 36x12x0.5 , the flat cantilever has resonant frequency of 746 kHz. Meanwhile, with this size but corrugation width of 6 and depth of 0.4 , the corrugated cantilever reaches the resonant frequency at 1.252 MHz.

Wide Bandgap Semiconductors - Nanowires of p- and n-type Silicon Carbide

ABSTRACTMonocrystalline nanowires of cubic silicon carbide were synthesized using a combined sol-gel and carbothermal reduction process in which tetraethoxysilane was used as primary sili-con and sucrose as carbon source. The diameters of the as-grown nanowires varied depending on process parameters from several tens to several hundreds nanometers, whereas the length of the wires was located in the millimetre region. By precisely controlling the atomic ratio of Si / C, silicon carbide nano wires were synthesized exclusively and pure without the presence of resid-ual carbon or unwanted silica, thus leads to semi-insulating behaviour. Supported by their consis-tence the silicon carbide micro or nano wires can be processed to textile or felt structures and are therefore usable for many applications such as for fireproof clothing, high temperature or chemi-cal filters and composite materials. Additionally during sol-gel synthesis the silicon carbide mi-cro / nano wires were easily doped to achieve p- or n-conduction, guiding to new applications in the field of wide bandgap semiconductors. The structure of 3C-SiC micro and nano wires was determined using scanning electron microscopy, X-ray diffraction, nuclear magnetic resonance and fourier transform infrared spectroscopy. The electronic properties were studied using elec-tron paramagnetic resonance spectroscopy, Hall effect and current-voltage measurements.