• Title/Summary/Keyword: Electronic devices

Search Result 4,580, Processing Time 0.036 seconds

SOl Pressure Sensors (SOI 압력(壓力)센서)

  • Chung, Gwiy-Sang;Ishida, Makoto;Nakamura, Tetsuro
    • Journal of Sensor Science and Technology
    • /
    • v.3 no.1
    • /
    • pp.5-11
    • /
    • 1994
  • This paper describes the characteristics of a piezoresistive pressure sensor fabricated on a SOI (Si-on-insulator) structure, in which the SOI structures of Si/$SiO_{2}$/Si and Si/$Al_{2}O_{3}$/Si were formed by SDB (Si-wafer direct bonding) technology and hetero-epitaxial growth, respectively. The SOI pressure sensors using the insulator of a SOI structure as the dielectrical isolation layer of piezoresistors, were operated at higher temperatures up to $300^{\circ}C$. In the case of pressure sensors using the insulator of a SOI structure as an etch-stop layer during the formation of thin Si diaphragms, the pressure sensitivity variation of the SOI pressure sensors was controlled to within a standard deviation of ${\pm}2.3%$ over 200 devices. Moreover, the pressure sensors fabricated on the double SOI ($Si/Al_{2}O_{3}/Si/SiO_{2}/Si$) structures formed by combining SDB technology with epitaxial growth also showed very excellent characteristics with high-temperature operation and high-resolution.

  • PDF

Scanning Kelvin Probe Microscope analysis of Nano-scale Patterning formed by Atomic Force Microscopy in Silicon Carbide (원자힘현미경을 이용한 탄화규소 미세 패터닝의 Scanning Kelvin Probe Microscopy 분석)

  • Jo, Yeong-Deuk;Bahng, Wook;Kim, Sang-Cheol;Kim, Nam-Kyun;Koo, Sang-Mo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2009.11a
    • /
    • pp.32-32
    • /
    • 2009
  • Silicon carbide (SiC) is a wide-bandgap semiconductor that has materials properties necessary for the high-power, high-frequency, high-temperature, and radiation-hard condition applications, where silicon devices cannot perform. SiC is also the only compound semiconductor material. on which a silicon oxide layer can be thermally grown, and therefore may fabrication processes used in Si-based technology can be adapted to SiC. So far, atomic force microscopy (AFM) has been extensively used to study the surface charges, dielectric constants and electrical potential distribution as well as topography in silicon-based device structures, whereas it has rarely been applied to SiC-based structures. In this work, we investigated that the local oxide growth on SiC under various conditions and demonstrated that an increased (up to ~100 nN) tip loading force (LF) on highly-doped SiC can lead a direct oxide growth (up to few tens of nm) on 4H-SiC. In addition, the surface potential and topography distributions of nano-scale patterned structures on SiC were measured at a nanometer-scale resolution using a scanning kelvin probe force microscopy (SKPM) with a non-contact mode AFM. The measured results were calibrated using a Pt-coated tip. It is assumed that the atomically resolved surface potential difference does not originate from the intrinsic work function of the materials but reflects the local electron density on the surface. It was found that the work function of the nano-scale patterned on SiC was higher than that of original SiC surface. The results confirm the concept of the work function and the barrier heights of oxide structures/SiC structures.

  • PDF

A New Folded Corrugated SIW with DC Biasing Capability (직류 전원 공급이 가능한 Folded Corrugated SIW)

  • Cho, Daekeun;Lee, Hai-Young
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
    • /
    • v.24 no.5
    • /
    • pp.508-514
    • /
    • 2013
  • Substrate integrated waveguide(SIW) constructed by two metal planes and conductive vias in a dielectric substrate, have all the conductors connected each other and hence, cannot be biased by DC sources. We propose a new folded corrugated substrate integrated waveguide(FCSIW) that can be DC-biased. Since the proposed FCSIW replaces the SIW conducting vias by folded open subs, it can supply the DC sources. The FCSIW has better transmission characteristics and 30 % less width than the common corrugated substrate integrated waveguide(CSIW) having a serious leakage generation problem. The FCSIW shows better insertion loss(1.49 dB) compared with that(3.08 dB) of the CSIW measured for 154 mm length devices and averaged at 9~15 GHz frequency band. No leakage has been observed from crosstalk measurements of the FCSIW.

The Implementation of Smart Raising Environment Management System based on Sensor Network and 3G Telecommunication (센서 네트워크와 3G 통신 기반 스마트 생장환경 관리시스템 개발)

  • Jeong, Kyong-Jin;Kim, Won-Jung
    • The Journal of the Korea institute of electronic communication sciences
    • /
    • v.6 no.4
    • /
    • pp.595-601
    • /
    • 2011
  • This study proposed the system to automatically control the optimized raising environment for vegetation, raised in an equipment house, in which u-IT agricultural technology concept was applied. The system consists of environment sensors such as temperature, humidity, etc., biosensors such as EC, PH, etc., and requested automatic control devices, in which they were automatically controlled by the software system. The system is established in client systems, installed in each equipment house and the server system, collecting data from each client system as well. In addition, the system collects each farmer's data through the Internet and 3G network. In this phase, collected raising environment data comes to be analyzed in order to find out the optimized vegetation raising environment, finally, which is visualized and used for consulting each farmer.

High power X-band SSPA Design using Gysel Power Combiner (Gysel 전력결합기를 이용한 고출력 X-band SSPA 설계)

  • Lee, Sang-Rok;Lim, Eun-Jae;Rhee, Young-Chul
    • The Journal of the Korea institute of electronic communication sciences
    • /
    • v.9 no.4
    • /
    • pp.425-432
    • /
    • 2014
  • Necessity of compact X-band solid-state weather radar is required to provide weather data, which generate locally in a lot of Korea's mountainous area, rather than tube-type radar. Solid State Power Amplifier (SSPA) for using Dual-polarization method in weather radar is able to obtain desired high output by combining many low output power devices in parallel. Thus, Power combiner applying to high-output power amplifier has disadvantages such as path loss, ballast resistance problem by high frequency and high power, heat release. Therefore, In this paper we demonstrated the excellence of isolation, which is the result from modified Gysel power combiner. As a result, we designed X-band 250W solid state power amplifier with peak power 54dBm, 25% power efficiency for weather radar.

Security Authentication Technique using Hash Code in Wireless RFID Environments (무선 RFID 환경에서 해시코드를 이용한 EPC 코드 보안)

  • Lee, Cheol-Seung
    • The Journal of the Korea institute of electronic communication sciences
    • /
    • v.14 no.6
    • /
    • pp.1077-1082
    • /
    • 2019
  • The development of computing technology and networking has developed into a fundamental technology of the Fourth Industrial Revolution, which provides a ubiquitous environment. In the ubiquitous environment, the IoT environment has become an issue so that various devices and the things can be actively accessed and connected. Also, the RFID system using the wireless identification code attaches an RFID tag to the object, such as the production and distribution of products. It is applied to the management very efficiently. EPCglobal is conducting a research on RFID system standardization and various security studies. Since RFID systems use wireless environment technology, there are more security threats than wire problems. In particular, failure to provide confidentiality, indistinguishability, and forward safety could expose them to various threats in the Fourth Industrial Revolution. Therefore, this study analyzes the standard method of EPCgolbal and proposes RFID security method using hash code that can consider the amount of computation.

Development of LoRaWAN IoT Automatic Meter Reading Systems (LoRaWAN IoT 원격검침장치 개발)

  • Park, Jae-Sam
    • The Journal of the Korea institute of electronic communication sciences
    • /
    • v.15 no.5
    • /
    • pp.913-922
    • /
    • 2020
  • In this paper, we propose a LoRa communication module using the LoRa RF module of Murata Electronics is designed to configure the IoT digital meter remote meter reading and a method of configuring a remote meter reading network by collecting multiple meter data in a DCU (Data Concentrate Unit) to configure a network with LoRaWAN. The developed system can be installed more easily and economically in the network configuration than the existing system by allowing the meter to be directly connected to the network or matched with a DCU to connect to the network according to the configuration of the consumer. The developed system was constructed using a digital water meter as an example, but it can also be applied to remote meter reading of the metered values of other meters such as electricity, water, gas, hot water and calorie meters. The main development contents are the design, configuration, and construction of digital meters, LoRa modules and DCUs, and how to connect the LoRaWAN network and transmit meter data to the server. By networking these devices, the system is configured, and the actual LoRaWAN communication is tested and the result is shown.

A Study on Stable Operation of Boost DC-DC Converter Circuit with 3-pole 2-zero Compensation Circuit (3-극점 2-영점 보상 회로가 적용된 승압형 DC-DC 컨버터 회로의 안정적 동작에 관한 연구)

  • Choi, Gun-Woo;Jung, Hai-Young;Lee, Seok-Hyun
    • The Journal of the Korea institute of electronic communication sciences
    • /
    • v.15 no.5
    • /
    • pp.923-930
    • /
    • 2020
  • In modern society, various DC power supplies are required to operate the system circuits of various electric devices. A stable DC supply is essential for the normal operation of the circuit and the importance of the converter for this is very high. This study proposed a PWM DC-DC converter circuit that applied a 3-pole 2-zero voltage controller to a KY converter, a step-up DC-DC converter, to maintain a stable supply of output voltage regardless of load fluctuations. In order to prove the normal operation characteristics of the proposed converter circuit, a PSIM simulation and a circuit operation experiment on the PCB board were performed in comparison with the conventional converter circuit.

Photoluminescence Properties of CaNb2O6:RE3+ (RE= Sm, Eu) Phosphors (CaNb2O6:RE3+ (RE= Sm, Eu) 형광체의 광학 특성)

  • Joeng, Woon Hwan;Cho, Shinho
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.27 no.7
    • /
    • pp.477-482
    • /
    • 2014
  • $CaNb_2O_6:RE^{3+}$ (RE=Sm or Eu) phosphor powders were prepared with different contents of activator ions by using solid-state reaction method. The X-ray diffraction patterns exhibited that the phosphors synthesized with different activator ions showed an orthorhombic system with a main (131) diffraction peak. The maximum size of the grain particles, determined from the measurement of scanning electron microscopy, was observed at 0.05 mol of $Eu^{3+}$ ions and at 0.01 mol of $Sm^{3+}$. As for the $Eu^{3+}$-doped phosphor powders, the excitation spectra were composed of a broad band peaked at 278 nm and several weak bands in the range of 350~500 nm, and the highest red emission spectrum was observed at 0.15 mol of $Eu^{3+}$ ions. As for the $Sm^{3+}$-activated phosphor powders, three strong emission bands under excitation at 273 nm were observed at 570, 612, and 659 nm, respectively. The intensities of all the emission bands approached maxima for 0.05 mol of $Sm^{3+}$ ions. The optical properties show that the $Eu^{3+}$- or $Sm^{3+}$-doped $CaNb_2O_6$ powders are promising red-orange emitting phosphor powders applicable to full-color photonic devices.

Electrical Characteristic of Power MOSFET with Zener Diode for Battery Protection IC

  • Kim, Ju-Yeon;Park, Seung-Uk;Kim, Nam-Soo;Park, Jung-Woong;Lee, Kie-Yong;Lee, Hyung-Gyoo
    • Transactions on Electrical and Electronic Materials
    • /
    • v.14 no.1
    • /
    • pp.47-51
    • /
    • 2013
  • A high power MOSFET switch based on a 0.35 ${\mu}m$ CMOS process has been developed for the protection IC of a rechargeable battery. In this process, a vertical double diffused MOS (VDMOS) using 3 ${\mu}m$-thick epi-taxy layer is integrated with a Zener diode. The p-n+Zener diode is fabricated on top of the VDMOS and used to protect the VDMOS from high voltage switching and electrostatic discharge voltage. A fully integrated digital circuit with power devices has also been developed for a rechargeable battery. The experiment indicates that both breakdown voltage and leakage current depend on the doping concentration of the Zener diode. The dependency of the breakdown voltage on doping concentration is in a trade-off relationship with that of the leakage current. The breakdown voltage is obtained to exceed 14 V and the leakage current is controlled under 0.5 ${\mu}A$. The proposed integrated module with the application of the power MOSFET indicates the high performance of the protection IC, where the overcharge delay time and detection voltage are controlled within 1.1 s and 4.2 V, respectively.