• Title/Summary/Keyword: blocking oxide

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Electrical Characteristics of Triple-Gate RSO Power MOSFET (TGRMOS) with Various Gate Configurations and Bias Conditions

  • Na, Kyoung Il;Won, Jongil;Koo, Jin-Gun;Kim, Sang Gi;Kim, Jongdae;Yang, Yil Suk;Lee, Jin Ho
    • ETRI Journal
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    • v.35 no.3
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    • pp.425-430
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    • 2013
  • In this paper, we propose a triple-gate trench power MOSFET (TGRMOS) that is made through a modified RESURF stepped oxide (RSO) process, that is, the nitride_RSO process. The electrical characteristics of TGRMOSs, such as the blocking voltage ($BV_{DS}$) and on-state current ($I_{D,MAX}$), are strongly dependent on the gate configuration and its bias condition. In the nitride_RSO process, the thick single insulation layer ($SiO_2$) of a conventional RSO power MOSFET is changed to a multilayered insulator ($SiO_2/SiN_x/TEOS$). The inserted $SiN_x$ layer can create the selective etching of the TEOS layer between the gate oxide and poly-Si layers. After additional oxidation and the poly-Si filling processes, the gates are automatically separated into three parts. Moreover, to confirm the variation in the electrical properties of TGRMOSs, such as $BV_{DS}$ and $I_{D,MAX}$, simulation studies are performed on the function of the gate configurations and their bias conditions. $BV_{DS}$ and $I_{D,MAX}$ are controlled from 87 V to 152 V and from 0.14 mA to 0.24 mA at a 15-V gate voltage. This $I_{D,MAX}$ variation indicates the specific on-resistance modulation.

Characterization of the Vertical Position of the Trapped Charge in Charge-trap Flash Memory

  • Kim, Seunghyun;Kwon, Dae Woong;Lee, Sang-Ho;Park, Sang-Ku;Kim, Youngmin;Kim, Hyungmin;Kim, Young Goan;Cho, Seongjae;Park, Byung-Gook
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.17 no.2
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    • pp.167-173
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    • 2017
  • In this paper, the characterization of the vertical position of trapped charges in the charge-trap flash (CTF) memory is performed in the novel CTF memory cell with gate-all-around structure using technology computer-aided design (TCAD) simulation. In the CTF memories, injected charges are not stored in the conductive poly-crystalline silicon layer in the trapping layer such as silicon nitride. Thus, a reliable technique for exactly locating the trapped charges is required for making up an accurate macro-models for CTF memory cells. When a programming operation is performed initially, the injected charges are trapped near the interface between tunneling oxide and trapping nitride layers. However, as the program voltage gets higher and a larger threshold voltage shift is resulted, additional charges are trapped near the blocking oxide interface. Intrinsic properties of nitride including trap density and effective capture cross-sectional area substantially affect the position of charge centroid. By exactly locating the charge centroid from the charge distribution in programmed cells under various operation conditions, the relation between charge centroid and program operation condition is closely investigated.

ZnO Based All Transparent UV Photodetector with Functional SnO2 Layer (SnO2 기능성 박막을 이용한 ZnO 기반의 투명 UV 광검출기)

  • Lee, Gyeong-Nam;Lee, Joo-Hyun;Kim, Joondong
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.67 no.1
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    • pp.68-74
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    • 2018
  • All transparent UV photodetector based on ZnO was fabricated with structure of NiO/ZnO/$SnO_2$/ITO by using RF and DC magnetron sputtering system. ZnO was deposited with 4 inch ZnO target (purity 99.99%) for a quality film. In order to build p-n junction up, p-type NiO was formed on n-type ZnO by using reactive sputtering method. The indium tin oxide (ITO) which is transparent conducting oxide (TCO) was applied as a transparent electrode for transporting electrons. To improve the UV photodetector performance, a functional $SnO_2$ layer was selected as an electron transporting and hole blocking layer, which actively controls the carrier movement, between ZnO and ITO. The photodetector (NiO/ZnO/$SnO_2$/ITO) shows transmittance over 50% as similar as the transmittance of a general device (NiO/ZnO/ITO) due to the high transmittance of $SnO_2$ for broad wavelengths. The functional $SnO_2$ layer for band alignment effectively enhances the photo-current to be $15{\mu}A{\cdot}cm^{-2}$ (from $7{\mu}A{\cdot}cm^{-2}$ of without $SnO_2$) with the quick photo-responses of rise time (0.83 ms) and fall time (15.14 ms). We demonstrated the all transparent UV photodetector based on ZnO and suggest the route for effective designs to enhance performance for transparent photoelectric applications.

A Study on Improvement and Degradation of Si/SiO2 Interface Property for Gate Oxide with TiN Metal Gate

  • Lee, Byung-Hyun;Kim, Yong-Il;Kim, Bong-Soo;Woo, Dong-Soo;Park, Yong-Jik;Park, Dong-Gun;Lee, Si-Hyung;Rho, Yong-Han
    • Transactions on Electrical and Electronic Materials
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    • v.9 no.1
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    • pp.6-11
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    • 2008
  • In this study, we investigated effects of hydrogen annealing (HA) and plasma nitridation (PN) applied in order to improve $Si/SiO_2$ interface characteristics of TiN metal gate. In result, HA and PN showed a positive effect decreasing number of interface state $(N_{it})$ respectively. After FN stress for verifying reliability, however, we identified rapid increase of $N_{it}$ for TiN gate with HA, which is attributed to hydrogen related to a change of $Si/SiO_2$ interface characteristic. In contrast to HA, PN showed an improved Nit and gate oxide leakage characteristic due to several possible effects, such as blocking of Chlorine (Cl) diffusion and prevention of thermal reaction between TiN and $SiO_2$.

Field Gas-Sparging Tests for In Situ Aerobic Cometabolism of Trichloroethylene(TCE)

  • Kim Young;Istok Jonathan D.;Semprini Lewis;Oa Sung-Wook
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2006.04a
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    • pp.54-56
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    • 2006
  • Single-well-gas-sparging tests were developed and evaluated for assessing the feasibility of in-situ aerobic cometabolism of trichloroethylene (TCE), using propane as a growth substrate. To evaluate transport characteristics of dissolved solutes [sulfur hexafluoride (SF6) or bromide (non-reactive tracers), propane (a growth substrate), ethylene, propylene (nontoxic surrogates to probe for CAH transformation activity), and DO], push-pull transport tests were performed. Mass balance showed about 90% of the injected bromide and about 80% of the injected SF6 were recovered, and the recoveries of other solutes were comparable with bromide and slightly higher than SF6. A series of Gas-Sparging Biostimulation tests were performed by sparging propane/oxygen/argon/SF6 gas mixtures, and temporal ground water samples were obtained from the injection well under natural gradient 'drift' conditions. The decreased time for propane depletion and the longer time to deplete SF6 as a conservative tracer indicate the progress of biostimulation. Gas-Sparging Activity tests were performed. .Propane utilization, DO consumption, and ethylene and propylene cometabolism were well demonstrated. The stimulated propane-utilizers cometabolized ethylene and propylene to produce ethylene oxide and propylene oxide, as cometabolic by-products, respectively. Gas-Sparging Acetylene Blocking tests were performed by sparging gas mixtures including acetylene to demonstrate the involvement of monooxygenase enzymes. Gas substrate degradation was essentially completely Inhibited in the presence of acetylene, and no production of the corresponding oxides was also observed. The Gas-Sparging tests supports the evidences that the successive stimulation of propane-oxidizing microorganisms, cometabolic transformation of ethylene and propylene by the enzyme responsible for methane and propane degradation.

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Anti-inflammatory Effect of Dangyuja (Citrus grandis Osbeck) Leaves in LPS-stimulated RAW 264.7 Cells

  • Yang, Eun-Jin;Lee, Hye-Ja;Kang, Gyeoung-Jin;Park, Sun-Soon;Yoon, Weon-Jong;Kang, Hee-Kyoung;Cho, So-Mi Kim;Yoo, Eun-Sook
    • Food Science and Biotechnology
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    • v.18 no.5
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    • pp.1063-1070
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    • 2009
  • Dangyuja (Citrus grandis Osbeck) is a native plant growing only on Jeju Island in Korea. In this study, antiinflammatory effect of dangyuja leaves on a murine macrophage cell line was investigated. RAW 264.7 murine macrophage cells were stimulated with lipopolysaccharide (LPS, $1{\mu}g/mL$) to induce expression of pro-inflammatory markers [interleukin (IL)-6 and inducible nitric oxide synthase (iNOS)]. The crude extract (80% MeOH Ex.) and solvent fractions (hexane, $CHCl_3$, EtOAc, BuOH, and $H_2O$ Ex.) were obtained from dangyuja leaves. The $CHCl_3$ fraction inhibited the nitric oxide (NO) and IL-6 production in a dose-dependent manner. Also, the $CHCl_3$ fraction inhibited mRNA expression and protein levels of iNOS in a dose-dependent manner. Furthermore, the $CHCl_3$ fraction inhibited LPS-induced nuclear factor (NF)-${\kappa}B$ activation and phosphorylation of mitogen-activated protein kinases (MAPKs: ERK, JNK, and p38). These results suggest that dangyuja leaves may inhibit LPS-induced production of inflammatory markers by blocking NF-${\kappa}B$ and MAPKs signaling in RAW 264.7 cells.

The Write Characteristics of SONOS NOR-Type Flash Memory with Common Source Line (공통 소스라인을 갖는 SONOS NOR 플래시 메모리의 쓰기 특성)

  • An, Ho-Myoung;Han, Tae-Hyeon;Kim, Joo-Yeon;Kim, Byung-Cheul;Kim, Tae-Geun;Seo, Kwang-Yell
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.11a
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    • pp.35-38
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    • 2002
  • In this paper, the characteristics of channel hot electron (CHE) injection for the write operation in a NOR-type SONOS flash memory with common source line were investigated. The thicknesses of he tunnel oxide, the memory nitride, and the blocking oxide layers for the gate insulator of the fabricated SONOS devices were $34{\AA}$, $73{\AA}$, and $34{\AA}$, respectively. The SONOS devices compared to floating gate devices have many advantages, which are a simpler cell structure, compatibility with conventional logic CMOS process and a superior scalability. For these reasons, the introduction of SONOS device has stimulated. In the conventional SONOS devices, Modified Folwer-Nordheim (MFN) tunneling and CHE injection for writing require high voltages, which are typically in the range of 9 V to 15 V. However CHE injection in our devices was achieved with the single power supply of 5 V. To demonstrate CHE injection, substrate current (Isub) and one-shot programming curve were investigated. The memory window of about 3.2 V and the write speed of $100{\mu}s$ were obtained. Also, the disturbance and drain turn-on leakage during CHE injection were not affected in the SONOS array. These results show that CHE injection can be achieved with a low voltage and single power supply, and applied for the high speed program of the SONOS memory devices.

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Epitaxial Cobalt Silicide Formation using Co/Ti/(100) Si Structure (Co/Ti(100)Si 이중층을 이용한 에피텍셜 Co 실리사이드의 형성)

  • Kwon, Young-Jae;Lee, Chong-Mu;Bae, Dae-Lok;Kang, Ho-Kyu
    • Korean Journal of Materials Research
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    • v.8 no.6
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    • pp.484-492
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    • 1998
  • The formation mechanism of the epitaxial cobalt silicide from Co/Ti/OOO) Si structure has been investigated. The transition temperature of CoSi to CoSi, was found to increase with increasing the Ti interlayer thickness, which may be owing to the occupation of the tetrahedral sites by Ti atoms in the CoSi crystal structure as well as the blocking effect of the Ti interlayer on the diffusion of Co. Also, the Co- Ti-O ternary compound formed at the metal! Si interface at the begining of silicidation, which seems to play an important role in epitaxial growth of Co silicide. The final layer structures obtained after a rapid thermal annealing of the Cot Ti/( 100) Si bi-layer structure turned out to be Ti oxide/Co- Ti-Si/epi-$CoSi_2$/OOO)

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A Study on the Characteristics of Si-$SiO_2$ interface in Short channel SONOSFET Nonvolatile Memories (Short channel SONOSFET 비휘발성 기억소자의 Si-$SiO_2$ 계면특성에 관한 연구)

  • Kim, Hwa-Mok;Yi, Sang-Bae;Seo, Kwang-Yell;Kang, Chang-Su
    • Proceedings of the KIEE Conference
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    • 1993.07b
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    • pp.1268-1270
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    • 1993
  • In this study, the characteristics of Si-$SiO_2$ interface and its degradation in short channel SONOSFET nonvolatile memory devices, fabricated by 1Mbit CMOS process($1.2{\mu}m$ design rule), with $65{\AA}$ blocking oxide layer, $205{\AA}$ nitride layer, and $30{\AA}$ tunneling oxide layer on the silicon wafer were investigated using the charge pumping method. For investigating the Si-$SiO_2$ interface characteristics before and after write/erase cycling, charge pumping current characteristics with frequencies, write/erase cycles, as a parameters, were measured. As a result, average Si-$SiO_2$ interface trap density and mean value of capture cross section were determined to be $1.203{\times}10^{11}cm^{-2}eV^{-1}\;and\;2.091{\times}10^{16}cm^2$ before write/erase cycling, respectively. After cycling, when the write/erase cycles are $10^4$, average $Si-SiO_2$ interface trap density was $1.901{\times}10^{11}cm^{-2}eV^{-1}$. Incresing write/erase cycles beyond about $10^4$, Si-$SiO_2$ interface characteristics with write/erase cycles was increased logarithmically.

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Anti-Inflammatory Effect of Erigeron annuus L. Flower Extract through Heme Oxygenase-1 Induction in RAW264.7 Macrophages (RAW264.7 대식세포에서 Heme Oxygenase-1의 유도에 의한 개망초 (Erigeron annuus L.) 꽃 Methanol 추출물의 항염증 효과)

  • Sung, Mi-Sun;Kim, Young-Hwa;Choi, Young-Min;Ham, Hyeon-Mi;Jeong, Heon-Sang;Lee, Jun-Soo
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.40 no.11
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    • pp.1507-1511
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    • 2011
  • This study investigated the anti-inflammatory effect of Erigeron annuus L. flower (EAF) methanol extract. We examined the involvement of heme oxygenase-1 (HO-1) in the inhibitory activities of EAF methanol extract on nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. Cell viability and NO assays were performed. In addition, inducible nitric oxide synthase (iNOS) and HO-1 expressions were detected by Western blotting and blocking HO-1 activity on NO production. EAF methanol extract (25, 50, 100, 200 ${\mu}g$/mL) significantly inhibited LPS-stimulated NO production (p<0.05; 12.82, 9.61, 6.83, 2.52 ${\mu}m$) in a concentration-dependent manner. EAF methanol extract also reduced the expression of iNOS protein. The EAF methanol extract induced the expression of HO-1 in a dose-dependent manner. Blockage of HO-1 activity by zinc protoporphyrin suppressed EAF methanol extract-induced reductions in the production of NO. The present results suggest that EAF methanol extract has a potent anti-inflammatory effect in RAW264.7 macrophages through the induction of HO-1.