• Title/Summary/Keyword: Impact Ionization

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A study on SCR-based bidirectional ESD protection device with high holding voltage due to parallel NPN BJT (Parallel NPN BJT로 인한 높은 홀딩 전압을 갖는 SCR 기반 양방향 ESD 보호 소자에 관한 연구)

  • Jung, Jang-Han;Woo, Je-Wook;Koo, Yong-Seo
    • Journal of IKEEE
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    • v.25 no.4
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    • pp.735-740
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    • 2021
  • In this paper, we propose a new ESD protection device with high holding voltage with low current gain of parasitic NPN BJT by improving the structure of the existing LTDDSCR. The electrical characteristics of the proposed protection device were analyzed by HBM simulation using Synopsys' TCAD simulation, and the operation of the added BJT was confirmed by current flow, impact ionization and recombination simulation. In addition, the holding voltage characteristics were optimized with the design variables D1 and D2. As a result of the simulation, it was verified that the new ESD protection device has a higher holding voltage compared to the existing LTDDSCR and has a symmetrical bidirectional characteristic. Therefore, the proposed ESD protection device has high area efficiency when applied to an IC and is expected to improve the reliability of the IC.

Electron-Impact Ionization Mass Spectroscopic Studies of Acetylene and Mixed Acetylene-Ammonia Clusters as a Structure Probe

  • Sung Seen Choi;Kwang Woo Jung;Kyung Hoon Jung
    • Bulletin of the Korean Chemical Society
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    • v.13 no.5
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    • pp.482-486
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    • 1992
  • Ion-molecule reactions of acetylene and mixed acetylene-ammonia cluster ions are studied using an electron impact time-of-flight mass spectrometer. The present results clearly demonstrate that $(C_2H_2)_n^+$ cluster ion distribution represents a distinct magic number of n=3. The mass spectroscopic evidence for the enhanced structural stabilities of $[C_6H_4{\cdot}(NH_3)_m]^+$ (m=0-8) ions is also found along with the detection of mixed cluster $[(C_2H_2)_n{\cdot}(NH_3)_m]^+$ ions, which gives insight into the feasible structure of solvated ions. This is rationalized on the basis of the structural stability for acetylene clusters and the dissociation dynamics of the complex ion under the presence of solvent molecules.

The Study on Channel and Doping influence of MOSFET using TCAD (TCAD를 이용한 채널과 도핑 농도에 따른 MOSFET의 특성 분석)

  • 심성택;장광균;정정수;정학기;이종인
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2000.05a
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    • pp.470-473
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    • 2000
  • The metal-oxide-semiconductor field-effect transistor(MOSFET) has undergone many changes in the last decade in response to the constant demand for increased speed, decreased power, and increased patting density. The devices are scaled down day by day. Therefore, This paper investigates how MOSFET structures influence on transport properties in according to change of channel length and bias and, observes impact ionization between the drain and the gate. This paper proposes three models, i.e., conventional MOSFET, LDD MOSFET and EPI MOSFET. The gate lengths are 0.3$\mu\textrm{m}$ 0.15$\mu\textrm{m}$, 0.075$\mu\textrm{m}$ and scaling factor is λ = 2. We have presented MOSFET's characteristics such as I-V characteristic, impart ionization, electric field, using the TCAD. We have analyzed the adaptive channel and doping influences

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A Carbon Nanotube Field Emitter with a Triode Configuration for a Miniature Mass Spectrometer (초소형 질량분석기를 위한 삼극관 구조의 탄소나노튜브 전자방출원)

  • Lee, Yu-Ri;Lee, Ki-Jung;Hong, Nguyen Tuan;Lee, Soon-Il;Yang, Sang-Sik
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.61 no.7
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    • pp.1001-1006
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    • 2012
  • This paper presents a carbon nanotube (CNT) triode-structure field emitter as an ion source in a micro time-of-flight mass spectrometer(TOF-MS). In the ion source by field emission, the electrons emitted from cathodes under an electric field accelerated to the anode and ionize gas molecules by impact before arriving the anode. The generated positive ions are to be accelerated to the ion collector. Whereas most of ions are drawn to the cathodes in diode field emitters, a grid in the triode field emitter prevents the ions from being drawn to the cathodes. The triode field emitter is fabricated by micromachining. The cathode is composed of six CNT cylinders. The total size of the fabricated device is $8.0{\times}7.3{\times}1.9mm^3$. The anode and the grid current of the fabricated CNT field emitter were measured for various anode and grid voltages. When the anode and the grid voltages are 1000 V and 990 V, respectively, the emission current passing through the ionization region is 8.6 ${\mu}A$, which is a sufficient emission current for ionization and mass spectrometry.

A study on the derivatization technique for tamoxifen metabolites in human urine by gas chromatography/mass spectrometry (기체크로마토그래피/질량분석기를 이용한 인체 내 뇨시료에서의 Tamoxifen 대사체 검출을 위한 유도체화 연구)

  • Kim, Yunje;Lee, Yoonjung
    • Analytical Science and Technology
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    • v.17 no.4
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    • pp.322-336
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    • 2004
  • The improved derivatization technique of tamoxifen metabolite in human urine is described for the acylation method that they are substituted by derivatization reagent like acyl anhydride for use of gas chromatography/mass spectrometry. The hydroxyl group of tamoxifen metabolite was derivatized by trifluoroacetic anhydride (TFAA), pentafluoroacetic anhydride (PFPA) and heptaflorobutylic anhydride (HFBA). It was investigated to the gas chromatography/mass spectrometry (GC/MS) technique use negative ion chemical ionization (NCI), positive ion chemical ionization (PCI) and electron impact (EI). In acylation of the metabolites of tamoxifen, the effective reaction temperature and time were shown to be at $50^{\circ}C$ for 30 min. The 4-hydroxytamoxifen, which is known to major metabolite of tamoxifen, was not detected in human urine, whileas the hydroxymethoxytamoxifen was detected. We thought that this result was from the single dose of tamoxifen.

Realistic Simulations on Reverse Junction Characteristics of SiC and GaN Power Semiconductor Devices

  • Wei, Guannan;Liang, Yung C.;Samudra, Ganesh S.
    • Journal of Power Electronics
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    • v.12 no.1
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    • pp.19-23
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    • 2012
  • This paper presents a practical methodology for realistic simulation on reverse characteristics of Wide Bandgap (WBG) SiC and GaN p-n junctions. The adjustment on certain physic-based model parameters, such as the trap density and photo-generation for SiC junction, and impact ionization coefficients and critical field for GaN junction are described. The adjusted parameters were used in Synopsys Medici simulation to obtain a realistic p-n junction avalanche breakdown voltage. The simulation results were verified through benchmarking against independent data reported by others.

Protein Expression Profiling of Infected Murine Macrophage Cells (RAW 264.7) by Bacillus anthracis Spores

  • Seo Gwi-Moon;Nam Jeong-Ah;Oh Kwang-Gun;Chai Young-Gyu
    • Proceedings of the Microbiological Society of Korea Conference
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    • 2003.05a
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    • pp.77-79
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    • 2003
  • Current therapeutic strategies far anthrax have had no significant impact on anthrax mortality over the last several decades. This study used a matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) discovery platform to generate protein expression profiles in search of overexpressed proteins in murine macrophage cells (RAW264.7) which infected with Bacillus anthracis spores as potentially novel molecular targets. Two differentially expressed proteins were identified in infected murine macrophage cells as Syndapin and CDC46, respectively. Syndapins are potential links between the cortical actin cytoskeleton and endocytosis. Other two proteins were identified from murine macrophage cells infected with avirulent spores as ITBG-2 (CD18) and HSPA5, respectively. These data demonstrate the feasibility of using a MALDI-TOF platform to generate protein expression profiles and identify potential molecular targets for anthrax therapeutics.

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The Study of Reliability by SILC Characteristics in Silicon Oxides (SILC 특성에 의한 실리콘 산화막의 신뢰성 연구)

  • 강창수
    • Proceedings of the IEEK Conference
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    • 2002.06b
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    • pp.17-20
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    • 2002
  • This study has been investigated that traps generated inside of the oxide and at the oxide interfaces by the stress bias voltage. The traps are charged near the cathode with negative charge and charged near the anode with positive charge. The charge state of the traps can easily be changed by application of low voltages after the stress high voltage. These trap generation involve either electron impact ionization processes or high field generation processes. It determined to the relative traps locations inside the oxides ranges from 113.4A to 814A with capacitor areas of 10$^{-3}$ $\textrm{cm}^2$ The oxide charge state of traps generated by the stress high voltage contain either a positive or negative charge.

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SPECTRAL DIAGNOSTICS OF THE ENERGETIC PARTICLES IN SOLAR FLARES

  • FANG C.;DING M. D.;HENOUX J. C.;GAN W. Q.
    • Journal of The Korean Astronomical Society
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    • v.29 no.spc1
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    • pp.295-298
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    • 1996
  • Non-LTE calculations, with the non-thermal ionization effects included, indicated that for electron bombardment, the H$\alpha$ line is widely broadened and shows a strong central reversal. Significant enhancements at the line wings of Ly$\alpha$ and Ly$\beta$ are also predicted at the beginning of the impulsive phase of flares. For the proton bombardment, no strong broadening and no large central reversal are expected. However, due to proton-hydrogen charge exchange, the enhancements at the red wings of Ly$\alpha$ and Ly$\beta$ lines at the early impulsive phase of flares are significant. Our results show that the electron beam can also in some cases generate visible and UV continuum emission in white-light flares. However, at the onset phase, a negative flare may appear within several seconds, due to the increase of the H- opacity. Another spectroscopic signature of energetic particles, i.e. the impact polarization of atomic lines, is also mentioned.

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A model for neural trigger circuit using AlGaAs/GaAs MQW-IMD (AlGaAs/GaAs MQW-IMD를 사용하는 신경구동회로의 모델)

  • Song, Chung-Kun
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.32A no.4
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    • pp.47-56
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    • 1995
  • In this paper the model of the MQE-IMD-based neural trigger circuit is improved, where MQW-IMD is a new semiconductor device proposed and experimentally demonstrated by the author for the hardware implementation of the neural networks. The electron energy of AlXGa1-XAsbarrier is calculated by Ensemble Monte Carlo simulation according to the variation of Al mole fraction x and the applied electric field, whtich had been roughly estimated in the previous paper because of the difficulty to get the data. And in the consideration of the tunneling of the confined electrons within the quantum well the accuracy of the impact ionization rate is enhaned. Finally, the dependance of the frequency of pulse-train on the number of quantum wells can be calculated by modelling the effect of the distance of the induced positive charge from the cathode on the electric field at the cathode.

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