• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.7
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• pp.388-393
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• 2000

Hydrogen-sensing behaviors of Pd- and Pt-SiC Schottky diodes, fabricated on the same SiC substrate, have been systematically compared and analyzed as a function of hydrogen concentration and temperature by I-V and$\DeltaI-t$ methods under steady-state and transient conditions. The effects of hydrogen adsorption on the device parameters such as the barrier height are investigated. The significant differences in their hydrogen sensing characteristics have been examined in terms of sensitivity limit, linearity of response, response rate, and response time. For the investigated temperature range, Pd-SiC Schottky diode shows better performance for H2 detection than Pt-SiC Schottky diode under the same testing conditions. The physical and chemical mechanisms responsible for hydrogen detection are discussed. Analysis of the steady-state reaction kinetics using I-V method confirmed that the atomistic hydrogen process is responsible for the barrier height change in the diodes.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.1
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• pp.29-34
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• 2008

In this paper, we investigated electrical and physical characteristics of nickel silicide using rare-earth metals(Er, Yb, Tb, Dy), Incorporated Ytterbium into Ni-silicide is proposed to reduce work function of Ni-silicide for nickel silicided schottky barrier diode (Ni-silicided SBD). Nickel silicide makes ohmic-contact or low schottky barrier height with p-type silicon because of similar work function (${\phi}_M$) in comparison with p-type silicon. However, high schottky barrier height is formed between Ni-silicide and p-type substrate by depositing thin ytterbium layer prior to Ni deposition. Even though the ytterbium is deposited below nickel, ternary phase $Yb_xN_{1-x}iSi$ is formed at the top and inner region of Ni-silicide, which is believed to result in reduction of work function about 0.15 - 0.38 eV.

• Proceedings of the KIEE Conference
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• 1999.11d
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• pp.938-940
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• 1999

We have fabricated SiC Schottky diode for high temperature applications. SiC thin film for drift region has been deposited by ICP-CVD. In order to establish metallization conditions, we have extracted the device parameters of the Schottky diode from the forward I-V characteristics and the C-V characteristics as a function of temperature. The ideality factor was varied from 2.07 to 1.15 and the barrier height was also varied from 1.26eV to 1.92eV with increase of temperature. The reverse blocking voltage was 183 V.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.77-81
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• 2007

Pentacene was dissolved in N-methyspyrrolidone (NMP) and mixed with poly(3,4-ethylenedioxythiophene), poly(styrenesulfonate) (PEDOT:PSS). The solution color changed from deep purple to intense yellow. As the dissolution time increased, visible absorption decreased and ultraviolet (UV) absorption increased. PEDOT:PSS or Pentacene-PEDOT:PSS was spin-coated to control the layer thickness. Three-layered Schottky diodes consisting of Al, PEDOT:PSS or PEDOT:PSS-pentacene, and Au with thickness of 300nm, respectively, were fabricated. The current densities of $4.8{\mu}A/cm^2$ at 2.5MV/m and $660{\mu}A/cm^2$ at 1.9MV/m were obtained for the Au/PEDOT:PSS/Al and Au/Pentacene-PEDOT:PSS/Al Schottky diodes, respectively. The current density of the Schottky diode was enhanced by about two orders of magnitude by doping pentacene to PEDOT:PSS.

• Nuclear Engineering and Technology
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• v.55 no.1
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• pp.201-208
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• 2023

The dependence of the electrical characteristics on the fast neutron fluence of an epitaxial 4H-SiC Schottky barrier diode (SBD) was investigated. The 30 MeV cyclotron was used for fast neutron irradiation. The neutron fluences evaluated through Monte Carlo simulation were in the 2.7 × 10¹¹ to 1.45 × 10¹³ neutrons/cm² range. Current-voltage and capacitance-voltage measurements were performed to characterize the samples by extracting the parameters of the irradiated SBDs. Neutron-induced defects in the epitaxial layer were identified and quantified using a deep-level transient spectroscopy measurement system developed at the Korea Atomic Energy Research Institute. As the neutron fluence increased from 2.7 × 10¹¹ to 1.45 × 10¹³ neutrons/cm², the concentration of the Z_1/2 defects increased by approximately 20 times. The maximum defect concentration was estimated as 1.5 × 10¹⁴ cm^-3 at a neutron fluence of 1.45 × 10¹³ neutrons/cm².

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.11a
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• pp.163-166
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• 1998

The mechanism of methane sensing by Pd-SiC diode was investigated over the temperature range of 400~$600^{\circ}C$. The effects or methane gas reaction on the parameters such as barrier height, initial rate of methane gas reaction are investigated. The methane gas reaction kinetics on the device are also discussed. The physical and chemical mechanism responsible for methane detection are proposed. Analysis of steady-state reaction kinetics using I-V method confirmed that methane gas reaction processes are responsible for the barrier height change in the diode.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.18-18
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• 2009

최근 다양하게 연구되고 있는 무분극(nonpolar) 갈륨질화물(GaN) 소재는 자발분극(spontaneous polarization) 및 압전분극(piezoelectric polarization) 등이 발생하지 않아 높은 내부양자효율의 확보가 가능하며, 이러한 장점을 바탕으로 고효율 특성을 갖는 발광다이오드(light-emitting diode) 및 고속 전자소자 등으로의 적용을 위한 연구가 활발히 수행 중 이다. 하지만, 무분극 GaN LED의 구현 시, GaN 박막의 비등방성 성장으로 인한 박막의 막질 저하와 함께 표면에 혼재하는 Ga층과 N층에서 기인되는 절연층의 생성으로 인한 오믹전극 형성의 어려움이 대두되고 있다. 따라서, 고효율의 무분극 GaN LED 구현을 위해서는 무분극 GaN층의 질소층 제거를 위한 표면처리 공정과 더불어 금속/무분극 GaN층 간 발생되는 쇼트키 장벽층의 높이(Schottky barrier height)를 제어하는 연구가 선행되어야 한다. 본 논문에서는 무분극 GaN LED 적용을 위한 n-형 전극물질 및 오믹조건 구현을 위한 금속/무분극 GaN층간 SBH의 제어방법에 대한 연구를 수행하였다.

• KIEE International Transactions on Electrophysics and Applications
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• v.4C no.3
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• pp.111-116
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• 2004

The Ni/SiC Schottky diode was fabricated with the $\alpha$-SiC thin film grown by the ICP-CVD method on a (111) Si wafer. $\alpha$-SiC film has been grown on a carbonized Si layer in which the Si surface was chemically converted to a very thin SiC layer achieved using an ICP-CVD method at $700^{\circ}C$. To reduce defects between the Si and $\alpha$-SiC, the surface of the Si wafer was slightly carbonized. The film characteristics of $\alpha$-SiC were investigated by employing TEM (Transmission Electron Microscopy) and FT-IR (Fourier Transform Infrared Spectroscopy). Sputterd Ni thin film was used as the anode metal. The boundary status of the Ni/SiC contact was investigated by AES (Auger Electron Spectroscopy) as a function of the annealing temperature. It is shown that the ohmic contact could be acquired beyond a 100$0^{\circ}C$ annealing temperature. The forward voltage drop at 100A/cm was I.0V. The breakdown voltage of the Ni/$\alpha$-SiC Schottky diode was 545 V, which is five times larger than the ideal breakdown voltage of the silicon device. As well, the dependence of barrier height on temperature was observed. The barrier height from C- V characteristics was higher than those from I-V.

• Journal of Sensor Science and Technology
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• v.8 no.6
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• pp.448-453
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• 1999

A Pd-SiC Schottky diode for detection of hydrogen gas operating at high temperature was explored. Hydrogen-sensing behaviors of Pd-SiC Schottky diode were analyzed as a function of hydrogen concentration and temperature by I-V and ${\Delta}I$-t methods under steady-state and transient conditions. The effect of hydrogen adsorption on the barrier height was investigated. Analysis of the steady-state kinetics using I-V method confirmed that the atomistic hydrogen adsorption process is responsible for the barrier height change in the diode.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.275-275
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• 2008

This paper describe the fabrication of a Pd/polycrystalline 3C-SiC schottky diode and its characteristics, in which the polycrystalline 3C-SiC layer and Pd Schottky contact were deposited by using APCVD and sputter, respectively. Crystalline quality, uniformity, and preferred orientations of the Pd thin film were evaluated by SEM and XRD, respectively. Pd/poly 3C-SiC Schottky diodes were fabricated and characterized by I-V and C-V measurements. Its electric current density Js and barrier height voltage were measured as $2\times10^{-3}$ A/$cm^2$ and 0.58 eV, respectively. These devices were operated until about $400^{\circ}C$. Therefore, from these results, Pd/poly 3C-SiC Schottky devices have very high potential for high temperature chemical sensor applications.