A5021794448- Acoustic Wave Resonator Technologies
- Advanced MEMS and NEMS Technologies
- Analytical Chemistry and Sensors
- Gas Sensing Nanomaterials and Sensors
- Mechanical and Optical Resonators
- Ferroelectric and Piezoelectric Materials
- Advanced Sensor and Energy Harvesting Materials
- Advanced Chemical Sensor Technologies
- Electronic and Structural Properties of Oxides
- Phase-change materials and chalcogenides
- Magnetic and transport properties of perovskites and related materials
- Innovative Energy Harvesting Technologies
- Acoustic Wave Phenomena Research
- Ferroelectric and Negative Capacitance Devices
- Nanofabrication and Lithography Techniques
- Multiferroics and related materials
- Transition Metal Oxide Nanomaterials
- Engineering Applied Research
- Dielectric materials and actuators
- Thermal Radiation and Cooling Technologies
- Superconducting and THz Device Technology
- Advanced Fiber Optic Sensors
- Chalcogenide Semiconductor Thin Films
- Internet of Things and Social Network Interactions
- Advancements in Photolithography Techniques
Korea Institute of Materials Science
2024
Korea University
2017-2023
Electronics and Telecommunications Research Institute
2009-2021
Pohang University of Science and Technology
2018-2021
Korea University of Technology and Education
2015
Korea Electronics Technology Institute
2011
SK Group (United States)
2004
Hyundai Heavy Industries (South Korea)
2000
We present a surface-micromachined capacitive microphone with membrane center hole and back-plate supports. The proposed reduces air damping at the of increases sensitivity frequency response. supports allow for deep back-chamber prevent deformation back-plate. microelectromechanical-system (MEMS) is fabricated using fully CMOS-compatible processes. MEMS has 500 µm in diameter 30 diameter. A depth 100 formed by supporting structures. During fabrication, residual stress minimized PECVD...
In this paper, a high sensitivity surface micromachined absolute pressure sensor with an internal substrate reference cavity was developed. The vacuum is formed by direct etching of under the sensing diaphragm and sealing holes. It much smaller than that previously bulk sensors its fabrication process has full CMOS compatibility. Also thin nanofilm piezoresistor, which fabricated using process, improves performances. 300 × 15μm3 2.0μm thickness 150nm polysilicon piezoresistors. output 5.48 ±...
The vibrational characteristics of 3 types the acoustic diaphragms are investigated to enhance output performance piezoelectric ceramic speaker in a low-frequency range. In other achieve both higher sound pressure level and wider frequency range speaker, we have proposed rubber/resin bi-layer diaphragm. theoretical square-root dependence fundamental resonant on thickness Young's modulus diaphragm was verified by finite-element analysis simulation laser scanning vibrometer measurement....
This research reports efficient reducing method of graphene oxide for gas sensor application. Graphene has been known to response such as nitrogen (NO2) or ammonia (NH3) and change resistivity corresponding the concentration. Here we carried out reduction by hydriodic acid (HI) [1], NH2NH2 [2] thermal annealing [3] under H2 atmosphere compared sensing behavior each reduced oxide. We found that HI responded strongly (sensitivity 5%) 2%) 0.15%).
Thick film semiconductor gas sensors based on indium oxide were fabricated Si substrate. The sensing materials substrate characterized using optical microscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM), so on. They very fine uniform we found out that particle sizes about 20~30 nm through XRD analysis. Gas responses of measured in a chamber where flow was controlled by mass controller (MFC). Their resistance changes monitored real time data acquisition board personal...
Fine ordered stripe patterns are developed through the evaporative self-assembly of a PMMA-toluene solution and O2 plasma for applications to optical waveguide devices. The were formed by repeating "stick-slip" motion contact line in restricted geometry. High-quality patterned lines obtained removing residue pattern's sidewall using an asher.
Bi4-xLaxTi3O12 (BLT) ferroelectric thin films were prepared on a Pt/TiOx/SiO2/Si substrate using metalorganic decomposition (MOD) method, and their electrical properties evaluated with thickness, composition crystallization annealing temperature. Irrespective of the preparation conditions, BLT c-axis oriented, had dense surface morphology without pore to produce smooth Pt/BLT/Pt interfaces capacitor. The film thickness was controlled as 90 nm obtain low coercive voltage (2Vc) problem...
Thickness effects on dependences of physical and ferroelectric properties were investigated for two kinds Bi3.35La0.85Ti3O12 (BLT) film with c-axis-preferred random orientations. BLT films prepared Pt/TiOx/SiO2/Si substrates by the metalorganic decomposition (MOD) method, their crystalline orientation was controlled baking rapid thermal annealing (RTA) conditions. When scaling down thickness from 210 to 70 nm, c-axis-oriented showed a big reduction in switching polarization (P*-P∧) 13 6...
This paper presents an optimized method to improve the sound quality of ultra-thin piezoelectric micro-acoustic actuators. To achieve flat and smooth frequency response characteristics acoustic actuators, we have proposed elastic mass attached diaphragm. The effects on actuator were investigated by finite element analysis simulation laser scanning vibrometer measurement. Based modal vibrational characteristics, it was found that fabricated has a significant dip 1.32 kHz peak 2.24 kHz, which...
Abstract We present a new capacitive type surface micromachined MEMS microphone with improved sensitivity and frequency response. In contrast to the bulk microphones, shows advantages of CMOS compatibility no backside etching process [1] . However, shallow back chamber depth small sensing gap increase air damping on membrane reduce overall sensitivity. this paper, we proposed center-hole membrane. The reduces at center increases displacement. fabricated an displacement is increased 168% for...
The sensing materials of potentiometric CO2 sensors utilize alkali/alkali-earth metal carbonates or their combinations. However, lithium carbonate easily responds to humidity resulting in incorrect information regarding concentration. Herein, the authors report a new material combination (Li2CO3/BaCO3/LiOH/Ba(OH)2 (1:2:0.05:0.1 molar ratio)) for sensor that is not affected by humidity. electromotive force (EMF) using Li2CO3, BaCO3, LiOH, and Ba(OH)2 drifted 1.5% when relative was changed...
SrBi 2 Ta O 9 (SBT) film was crystallized to form fine grains and a smooth surface by rapid thermal annealing (RTA), but large rough main furnace annealing. The sequence of changed improve the morphology Pt/SBT interface leakage property Pt/SBT/Pt capacitor. For conventional before top electrode deposition, capacitor showed good switching polarization (P * -P ∧ ) 17 µC/cm high short fail rate 56% due interface. However, using new after deposition on RTA-treated SBT film, very resultant low...
Abstract The coiled-coil (CC) domain is a very important structural unit of proteins that plays critical roles in various biological functions. major oligomeric state CCs dimer, which can be either parallel or antiparallel. orientation each α-helix CC for the molecular function CC-containing proteins, but cannot determined easily by sequence-based prediction. We developed biochemical method assessing differences between and antiparallel homodimers named it ACCORD ( A ssessment tool...
In this paper, we present a concave-patterned TiN/PECVD-Si3N4 /TiN diaphragm micro-electro-mechanical system (MEMS) acoustic sensor based on polyimide sacrificial layer. The use of the spin-coated eliminates additional Al pad process conventional device fabrication due to simple O2 ashing release layer, simplifying photolithography process. Also, adjust for bottom-ported package, its was implemented be placed over back-plate. TiN/PECVD-Si3N4/TiN multi-layer formed with stress controllability...
Powder injection molding is a combined technique of traditional powder metallurgy and plastic molding. Since step in the process enables to produce complex shapes, has high design flexibility provides chance overcome limitations current manufacturing process. In this paper, optimization was discussed. The roughly divided into 5 steps from solids loading determination sintering, approaches for each detailed. Thereafter, industrial application described with hydrophobic surgical forceps, soft...