• Title/Summary/Keyword: Secondary Doping

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Boron Detection Technique in Silicon Thin Film Using Dynamic Time of Flight Secondary Ion Mass Spectrometry

  • Hossion, M. Abul;Arora, Brij M.
    • Mass Spectrometry Letters
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    • v.12 no.1
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    • pp.26-30
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    • 2021
  • The impurity concentration is a crucial parameter for semiconductor thin films. Evaluating the impurity distribution in silicon thin film is another challenge. In this study, we have investigated the doping concentration of boron in silicon thin film using time of flight secondary ion mass spectrometry in dynamic mode of operation. Boron doped silicon film was grown on i) p-type silicon wafer and ii) borosilicate glass using hot wire chemical vapor deposition technique for possible applications in optoelectronic devices. Using well-tuned SIMS measurement recipe, we have detected the boron counts 101~104 along with the silicon matrix element. The secondary ion beam sputtering area, sputtering duration and mass analyser analysing duration were used as key variables for the tuning of the recipe. The quantitative analysis of counts to concentration conversion was done following standard relative sensitivity factor. The concentration of boron in silicon was determined 1017~1021 atoms/㎤. The technique will be useful for evaluating distributions of various dopants (arsenic, phosphorous, bismuth etc.) in silicon thin film efficiently.

플라즈마 도핑 후 급속열처리법을 이용한 n+/p 얕은 접합 형성

  • Do, Seung-U;Seo, Yeong-Ho;Lee, Jae-Seong;Lee, Yong-Hyeon
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.11a
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    • pp.50-50
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    • 2009
  • In this paper, the plasma doping is performed on p-type wafers using $PH_3$ gas(10 %) diluted with He gas(90 %). The wafer is placed in the plasma generated with 200 W and a negative DC bias (1 kV) is applied to the substrate for 60 sec under no substrate heating. the flow rate of the diluted $PH_3$ gas and the process pressure are 100 sccm and 10 mTorr, respectively. In order to diffuse and activate the dopant, annealing process such as rapid thermal annealing (RTA) is performed. RTA process is performed either in $N_2$, $O_2$ or $O_2+N_2$ ambient at $900{\sim}950^{\circ}C$ for 10 sec. The sheet resistance is measured using four point probe. The shallow n+/p doping profiles are investigated using secondary ion mass spectromtry (SIMS). The analysis of crystalline defect is also done using transmission electron microscopy (TEM) and double crystal X-ray diffraction (DXRD).

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MnO2 as an Effective Sintering Aid for Enhancing Piezoelectric Properties of (K,Na)NbO3 Ceramics

  • Jeong, Seong-Kyu;Hong, In-Ki;Do, Nam-Binh;Tran, Vu Diem Ngoc;Cho, Seong-Youl;Taib, Weon Pil;Lee, Jae-Shin
    • Journal of Powder Materials
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    • v.17 no.5
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    • pp.399-403
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    • 2010
  • The effects of $MnO_2$ doping on the crystal structure, ferroelectric, and piezoelectric properties of (K,Na)$NbO_3$ (KNN) ceramics have been investigated. $MnO_2$ was found to be effective in enhancing the densification and grain growth during sintering. X-ray diffraction analysis indicated that Mn ions substituted B-site Nb ions up to 2 mol%, however, further doping induced unwanted secondary phases. In comparison with undoped KNN ceramics, the well developed microstructure and the substitution to B-sites in 2 mol% Mn-doped KNN ceramics resulted in significant improvements in both piezoelectric coupling coefficient and electromechanical quality factor.

Selective doping of Li-rich layered oxide cathode materials for high-stability rechargeable Li-ion batteries

  • Han, Dongwook;Park, Kwangjin;Park, Jun-Ho;Yun, Dong-Jin;Son, You-Hwan
    • Journal of Industrial and Engineering Chemistry
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    • v.68
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    • pp.180-186
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    • 2018
  • We report the discovery of Li-rich $Li_{1+x}[(Ni_{0.225}Co_{0.15}Mn_{0.625})_{1-y}V_y]O_2$ as a cathode material for rechargeable lithium-ion batteries in which a small amount of tetravalent vanadium ($V^{4+}$) is selectively and completely incorporated into the manganese sites in the lattice structure. The unwanted oxidation of vanadium to form a $V_2O_5-like$ secondary phase during high-temperature crystallization is prevented by uniformly dispersing the vanadium ions in coprecipitated $[(Ni_{0.225}Co_{0.15}Mn_{0.625})_{1-y}V_y](OH)_2$ particles. Upon doping with $V^{4+}$ ions, the initial discharge capacity (>$275mA\;h\;g^{-1}$), capacity retention, and voltage decay characteristics of the Li-rich layered oxides are improved significantly in comparison with those of the conventional undoped counterpart.

Structural Analysis of the Ectodomain of HIV Gp41 and Implication on the Gp41 Assisted Membrane Fusion

  • Ryu, Jae-Ryen;Lee, Jung;Suh, Mu-Jin;Yu, Yeong-Sook;Yu, Yeon-Gyu
    • Proceedings of the Korean Biophysical Society Conference
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    • 1996.07a
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    • pp.33-33
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    • 1996
  • An ectodomain of gp41, the transmembrane fusion protein of HIV, without the fusion peptide region was expressed using pET system in E. coli. The expressed protein gp41core, was isolated as inclusion body and was purified by ion-exchange chromatography after solubilized in 6M urea. The purified denatured protein was renaturated and the folded domain of gp41core was identified by the presence of the proteolysis resistence domain and a high content of ${\alpha}$-helical secondary structure. (omitted)

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N-type doping and band gap change of Calix adsorbed on Graphene

  • Park, Seon-Min;Yang, Se-Na;Kim, Gi-Jeong;Kim, Bong-Su;No, Gwang-Hyeon;Lee, Han-Gil
    • Proceedings of the Korean Vacuum Society Conference
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    • 2010.02a
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    • pp.341-341
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    • 2010
  • Electronic structure of Calix adsorbed on epitaxial graphene (EG) was investigated using high resolution photoemission spectroscopy (HRPES). Increasing the deposition of calix molecule, we found that EG becomes n-type doping using secondary edge measurement (work function change). As we observe bonding nature of O 1s peak, we found that single O 1s peak can be clearly distinguished in the spectra indicating equivalent adsorption state. Finally, we were able to control the band gap of EG using valence band spectra as we change the amount of calix molecule. In this study, we will propose the possibility of band gap modulation of EG using calix molecule.

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Preparation of Spherical Li4Ti5O12 and the Effect of Y and Nb Doping on the Electrochemical Properties as Anode Material for Lithium Secondary Batteries (리튬이온이차전지용 구형 Li4Ti5O12 음극 합성 및 Y와 Nb 도핑에 따른 전기화학적 특성)

  • Ji, Mi-Jung;Kwon, Yong-Jin;Kim, Eun-Kyung;Park, Tae-Jin;Jung, Sung-Hun;Choi, Byung-Hyun
    • Journal of the Korean Ceramic Society
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    • v.49 no.6
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    • pp.659-662
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    • 2012
  • Yttrium (Y) and niobium (Nb) doped spherical $Li_4Ti_5O_{12}$ were synthesized to improve the energy density and electrochemical properties of anode material. The synthesized crystal was $Li_4Ti_5O_{12}$, the particle size was less than $1{\mu}m$ and the morphology was spherical and well dispersed. The Y and Nb optimal doping amounts were 1 mol% and 0.5 mol%, respectively. The initial capacity of the dopant discharge and charge capacity were respectively 149mAh/g and 143 mAh/g and were significantly improved compared to the undoped condition at 129 mAh/g. Also, the capacity retention of 0.2 C/5 C was 74% for each was improved to 94% and 89%. It was consequently found that Y and Nb doping into the $Li_4Ti_5O_{12}$ matrix reduces the polarization and resistance of the solid electrolyte interface (SEI) layer during the electrochemical reaction.

A study on Ultrashallow PN junction formation by boron implantation in Silicon (실리콘에 Boron 이온 주입에 의한 Ultrashallow PN접합 형성에 관한 연구)

  • 김동수;정원채
    • Proceedings of the IEEK Conference
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    • 2000.06b
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    • pp.56-59
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    • 2000
  • In this paper, we have made a comparison between secondary ion mass spectroscopy(SIMS) data by the 5kcV-15keV boron implantation and computer simulation results. In order to make electrical activation of implanted carriers, thermal annealing are carried out by RTP method for 30s at 1000$^{\circ}C$ Two dimensional doping concentration distribution from different mask dimensions under inert gas annealing, dry-, and wet-oxidation condition were calculated and simulated with microtec simulator.

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$^{11}B$ Quadrupole Interaction Studies of Boron-doped Graphite Electrode for Lithium Secondary Battery

  • Lee, Youngil;Han, Duk-Young;Lee, Donghoon;Woo, Ae-Ja;Lee, Sam-Hyeon;Kim, Kyung-Han;Lee, Man-Ho
    • Journal of the Korean Magnetic Resonance Society
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    • v.3 no.2
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    • pp.90-99
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    • 1999
  • Doping of boron atoms in graphite has been well known method to increase the discharge capacity as the negative electrode material for lithium secondary battery. Herein, the boron-doped graphites are prepared by mixing 1, 2.5, 5, and 7 wt. % of boron carbide in carbon during the graphitizing process. The structural states of boron in boron-doped graphites are investigated by solid-state 11B NMR spectroscopy. The resonance lines for substitutional boron atoms are identified as the second order quadrupolar powder pattern with the quardrupole coupling constant, QCC = 3.36(2) MHz. The quantitative analysis of 11B NMR spectra with boron-doped graphite has also been performed via simulation.

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