측온저항체 온도센서용 Pt-Co 합금박막의 증착과 특성에 관한 연구

정귀상,노상수 ( Gwiy Sang Chung,Sang Soo Noh ) 한국센서학회 1998 센서학회지 Vol.7 No.1

Platinum-Cobalt alloy thin films were deposited on Al₂O₃ substrate by magnetron cosputtering for RTD temperature sensors. We made Pt-Co alloy resistance patterns on the Al₂O₃ substrate by lift-off method and investigated the physical and electrical characteristics of these films under various conditions, the input power, working vacuum, annealing temperature and time, and also after annealing these films. The resistivity and sheet resistivity of these films were decreased with increasing the annealing temperature. At input power of Pt : 4.4 W/㎠, Co : 6.91 W/㎠, working vacuum of 10 mTorr and annealing conditions of 800℃: and 60 min, the resistivity and sheet resistivity of Pt-Co thin films was 15μΩ·cm and 0.5Ω/□, respectively and the TCR value of Pt-Co alloy thin films with thickness of 3000Å were 3740ppm/℃ in the temperature range of 25∼600℃. These results indicate that Pt-Co alloy thin films have potentiality for the RTD temperature sensors.

측온저항체 온도센서용 백금 박막의 형성에 관한 연구

정귀상,노상수 ( Gwiy Sang Chung,Sang Soo Noh ) 한국전기전자재료학회 1996 전기전자재료학회논문지 Vol.9 No.9

극한 환경 MEMS용 옴익 접촉을 위한 다결정 3C-SiC 박막의 표면 처리 효과

정귀상,온창민,Chung, Gwiy-Sang,Ohn, Chang-Min 한국전기전자재료학회 2007 전기전자재료학회논문지 Vol.20 No.3

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.

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

정귀상,이태원,Chung, Gwiy-Sang,Lee, Tae-Won 한국전기전자재료학회 2009 전기전자재료학회논문지 Vol.22 No.4

This paper describes the characteristics of polycrystalline 3C-SiC doubly clamped beam micro resonators. The polycrystalline 3C-SiC doubly clamped beam resonators with $60{\sim}100{\mu}m$ lengths, $10{\mu}m$ width, and $0.4{\mu}m$ 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 $60{\sim}100{\mu}m$ long cantilevers, the fundamental frequency appeared at $373.4{\sim}908.1\;kHz$. 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.

CVD에 의한 고전력 디바이스용 단결정 3C-SiC 박막 성장

정귀상,심재철,Chung, Gwiy-Sang,Shim, Jae-Cheol 한국전기전자재료학회 2010 전기전자재료학회논문지 Vol.23 No.2

This paper describes that single crystalline 3C-SiC (cubic silicon carbide) thin films have been deposited on carbonized Si(100) substrates using hexamethyldisilane (HMDS, $Si_2(CH_3){_6}$) as a safe organosilane single precursor and a nonflammable mixture of Ar and $H_2$ gas as the carrier gas by APCVD at $1280^{\circ}C$. The deposition was performed under various conditions to determine the optimized growth condition. The crystallinity of the 3C-SiC thin film was analyzed by XRD (X-ray diffraction). The surface morphology was also observed by AFM (atomic force microscopy) and voids between SiC and Si interfaces were measured by SEM (scanning electron microscopy). Finally, residual strain and hall mobility was investigated by surface profiler and hall measurement, respectively. From these results, the single crystalline 3C-SiC film had a good crystal quality without defects due to viods, a low residual stress, a very low roughness.

다결정 3C-SiC 마이크로 공진기의 온도특성

정귀상,이태원,Chung, Gwiy-Sang,Lee, Tae-Won 한국전기전자재료학회 2009 전기전자재료학회논문지 Vol.22 No.4

This paper describes the temperature characteristics of polycrystalline 3C-SiC micro resonators. The $1.2{\mu}m$ and $0.4{\mu}m$ thick polycrystalline 3C-SiC cantilever and doubly clamped beam resonators with $60{\sim}100{\mu}m$ 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 $25{\sim}200^{\circ}C$. The TCF(Temperature Coefficient of Frequency) of 60, 80 and 100 On long cantilever resonators were -9.79, -7.72 and -8.0 ppm/$^{\circ}C$. On the other hand, TCF of 60, 80 and $100{\mu}m$ long doubly clamped beam resonators were -15.74, -12.55 and -8.35 ppm/$^{\circ}C$. Therefore, polycrystalline 3C-SiC resonators are suitable with RF MEMS devices and bio/chemical sensor applications in harsh environments.

알루미늄산화막을 매개층으로 이용한 백금 미세발열체의 특성

정귀상,노상수,최영규,김진한 ( Gwiy Sang Chung,Sang Soo Noh,Young Kyu Choi,Jin Han Kim ) 한국센서학회 1997 센서학회지 Vol.6 No.5

The electrical and physical characteristics of aluminum oxide and Pt thin films on it, deposited by reactive sputtering and DC magnetron sputtering, respectively, were analyzed with increasing annealing temperature(400∼800℃) by four point probe, SDM and XRD. Under 600 ℃ of annealing temperature. aluminum oxide had the properties of improving Pt adhesion to SiO₂ and insulation without chemical reaction to Pt thin films and the resistivity of Pt thin films was improved. But these properties of aluminum oxide and Pt thin films on it were degraded over 700℃ of annealing temperature because aluminum oxide was changed into metal aluminum and then reacted to Pt thin films deposited on it. The thermal characteristics of Pt micro heater were analyzed with Pt-RTD integrated on the same substrate. In the analysis of properties of Pt micro heater, active area was smaller size, Pt micro heater had better thermal characteristics. The temperature of Pt micro heater with active area, 200㎛ X 200㎛ was up to 400℃ with 1.5watts of the heating power.

AlN 버퍼층위에 증착된 다결정 3C-SiC 박막의 라만 산란 특성

정귀상,김강산,Chung, Gwiy-Sang,Kim, Kang-San 한국전기전자재료학회 2008 전기전자재료학회논문지 Vol.21 No.6

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.

진동 구동식 원통형 전자기 에너지 하베스터의 설계 및 해석

정귀상,류경일,Chung, Gwiy-Sang,Ryu, Kyeong-Il 한국전기전자재료학회 2010 전기전자재료학회논문지 Vol.23 No.11

This paper describes the design and analysis of vibration driven cylindric electromagnetic energy harvester. The proposed harvester consists with spring, coil and rear earth magnet. The design utilizes an electromagnetic transducer and its operating principle is based on the relative movement of a magnet pole with respect to a coil. In order to optimal design and analysis, ANSYS FEA (Finite Elements Analysis) and Matlab model were used to predict the magnetic filed density with vibration and the generated maximum output power with load resistance. The system was designed for 6 Hz of natural frequency and spring constant was 39.48 N/m between 2 mm and 6 mm of displacement in moving magnet. When moving magnet of system was oscillated, each model was obtained that induced voltage in the coil was generated 2.275 Vpp, 2.334 Vpp and 2.384 Vpp, respectively. Then maximum output powers of system at load resistance ($1303{\Omega}$) were generated $124.2{\sim}132.2\;{\mu}W$ during magnets input displacement of 3 mm and 6 Hz periodic oscillation.

단결정 SOI트랜스듀서 및 회로를 위한 Si 직접접합

정귀상,( Gwiy Sang Chung,Tetsuro Nakamura ) 한국센서학회 1992 센서학회지 Vol.1 No.1

This paper has been described a process technology for the fabrication of Si-on-insulator(SOI) transducers and circuits. The technology utilizes Si-wafer direct bonding(SDB) and mechanical-chemical(M-C) local polishing to create a SOI structure with a high-quality, uniformly thin layer of single-crystal Si. The electrical and piezoresistive properties of the resultant thin SOI films have been investigated by SOI MOSFET`s and cantilever beams, and confirmed comparable to those of bulk Si. Two kinds of pressure transducers using a SOI structure have been proposed. The shifts in sensitivity and offset voltage of the implemented pressure transducers using interfacial SiO₂ films as the dielectrical isolation layer of piezoresistors were less than -0.2% and +0.15, respectively, in the temperature range from -20℃ to +350℃. In the case of pressure transducers using interfacial SiO₂ films as an etch-stop layer during the fabrication of thin Si membranes, the pressure sensitivity variation can be controlled to within a standard deviation of ±2.3% from wafer to wafer. From these results, the developed SDB process and the resultant SOI films will offer significant advantages in the fabrication of integrated microtransducers and circuits.