• JSTS:Journal of Semiconductor Technology and Science
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• 제14권2호
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• pp.153-162
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• 2014

We show that carbon nanotube sensors with gold particles on the single-walled carbon nanotube (SWNT) network operate as Schottky barrier transistors, in which transistor action occurs primarily by varying the resistance of Au-SWNT junction rather than the channel conductance modulation. Transistor characteristics are calculated for the statistically simplified geometries, and the sensing mechanisms are analyzed by comparing the simulation results of the MOSFET model and Schottky junction model with the experimental data. We demonstrated that the semiconductor MOSFET effect cannot explain the experimental phenomena such as the very low limit of detection (LOD) and the logarithmic dependence of sensitivity to the DNA concentration. By building an asymmetric concentric-electrode model which consists of serially-connected segments of CNTFETs and Schottky diodes, we found that for a proper explanation of the experimental data, the work function shifts should be ~ 0.1 eV for 100 pM DNA concentration and ~ 0.4 eV for $100{\mu}M$.

• 전자공학회논문지A
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• 제33A권4호
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• pp.106-111
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• 1996

Schottky diodes are fabricated on laser annealed and unannealed polysilicon substrate and their electrical characteristics are studied and analyzed. Current of laser annealed devices are larger than that of unannealed devices because of grain growth, decrease of grain boundary and trap density, lowering of grain boundary barrier height, decrease of dopant segregation. At low forward bias (<0.7V), currents of unanealed devices are larger. Soft breakdown voltages of laser annealed devices are larger than that of unannealed devices.

• JSTS:Journal of Semiconductor Technology and Science
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• 제4권2호
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• pp.124-127
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• 2004

W/n-GaN Schottky diodes were irradiated with $^{60}Co\;{\gamma}-rays$ to doses up to 315Mrad. The barrier height obtained from current-voltage (I-V) measurements showed minimal change from its estimated initial value of ${\sim}0.4eV$ over this dose range, though both forward and reverse I-V characteristics show evidence of defect center introduction at doses as low as 150 Mrad. Post irradiation annealing at $500^{\circ}C$ increased the reverse leakage current, suggesting migration and complexing of defects. The W/GaN interface is stable to high dose of ${\gamma}-rays$, but Au/Ti overlayers employed for reducing contact sheet resistance suffer from adhesion problems at the highest doses.

• 한국전기전자재료학회논문지
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• 제24권11호
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• pp.911-914
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• 2011

We optimize electrical and optical properties of thermal and SF6 plasma treated indium tin oxide (ITO)/Al based reflector for high-power ultraviolet (UV) light-emitting diodes (LEDs). After thermal and $SF_6$ plasma treatments of ITO/Al reflector, the specific contact resistance decreased from $1.04{\times}10^{-3}\;{\Omega}{\cdot}cm^2$ to $9.21{\times}10^{-4}\;{\Omega}{\cdot}cm^2$, while the reflectance increased from 58% to 70% at the 365 nm wavelength. The low resistance and high reflectance of ITO/Al reflector are attributed to the reduced Schottky barrier height (SBH) between the ITO and AlGaN by large electronegativity of fluorine species and reduced interface roughness between the ITO and Al, respectively.

• 대한전자공학회논문지SD
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• 제39권10호
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• pp.25-34
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• 2002

본 논문에서는 코발트 실리사이드가 형성된 얕은 p+-n과 n+-p 접합의 전류-전압 특성을 분석하여 silicidation에 의해 형성된 Schottky contact 면적을 구하였다. 역방향 바이어스 영역에서는 Poole-Frenkel barrier lowering 효과가 지배적으로 나타나서 Schottky contact 효과를 파악하기가 어려웠다. 그러나 Schottky contact의 형성은 순방향 바이어스 영역에서 n+-p 접합의 전류-전압 (I-V) 동작에 영향을 미치는 것으로 확인되었다. 실리사이드가 형성된 n+-p 다이오드의 누설전류 증가는 실리사이드가 형성될 때 p-substrate또는 depletion area로 코발트가 침투퇴어 Schottky contact을 형성하거나 trap들을 발생시켰기 때문이다. 분석결과 perimeter intensive diode인 경우에는 silicide가 junction area까지 침투하였으며, area intensive junction인 경우에는 silicide가 비록 공핍층이나 p-substrate까지 침투하지는 않았더라도 공핍층 근처까지 침투하여 trap들을 발생시켜 누설전류를 증가시킴을 확인하였다. 반면 p+-n 다이오드의 경우 Schottky contact이발생하지 않았고 따라서 누설전류도 증가하지 않았다. n+-p 다이오드에서 실리사이드에 의해 형성된 Schottky contact 면적은 순방향 바이어스와 역방향 바이어스의 전류 전압특성을 동시에 제시하여 유도할 수 있었고 전체 접합면적의 0.01%보다 작게 분석되었다.

• 반도체디스플레이기술학회지
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• 제21권2호
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• pp.123-126
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• 2022

We investigated deep levels in n-type 4H-SiC epitaxy layer of the Positive-Intrinsic-Negative diode and Schottky barrier diodes by using deep level transient spectroscopy. Despite the excellent performance of 4H-SiC, research on various deep level defects still requires a lot of research to improve device performance. In Positive-Intrinsic-Negative diode, two defects of 196K and 628K are observed more than Schottky barrier diode. This is related to the action of impurity atoms infiltrating or occupying the 4H-SiC lattice in the ion implantation process. The I-V characteristics of the Positive-Intrinsic-Negative diode shows about ~100 times lower the leakage current level than Schottky barrier diode due to the grid structures in Positive-Intrinsic-Negative. As a result of comparing the capacitance of devices diode and Schottky barrier diode devices, it can be seen that the capacitance value lowered if it exists the P implantation regions from C-V characteristics.

• 반도체디스플레이기술학회지
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• 제20권4호
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• pp.68-71
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• 2021

In this paper, GaN-SBD devices with excellent breakdown voltage and frequency characteristics for use in high-power microwave wireless power transmission has been modeled for PSpice circuit simulation. The RF-DC conversion circuits were simulated and compared with a commercial Si-SBD device. Although the modeled GaN-SBD devices had lower RF-DC conversion efficiency compared to Si-SBD at 2.4 and 5.8 GHz, it was confirmed through PSpice circuit simulations that they can be used sufficiently according to the required application circuit in a high power situation.

• 전자공학회논문지
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• 제54권1호
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• pp.21-25
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• 2017

본 연구에서는 최근 차세대 전력 반도체로 관심을 받고 있는 단결정 ${\beta}-Ga_2O_3$를 이용한 쇼트키 배리어 다이오드 제작 및 특성 분석을 수행하였다. 쇼트키 배리어 다이오드는 Sn으로 도핑된 $2{\mu}m$ 두께의 저농도 N 타입 에피층 상에 Pt/Ti/Au 쇼트키 접합으로 제작되었으며 측정된 특성은 > 180 V의 항복전압, $1.26m{\Omega}{\cdot}cm^2$의 온 저항, 그리고 1 V의 순 방향 전압에서 $77A/cm^2$, 1.5 V에서 $473A/cm^2$의 순방향 전류 특성을 나타내었다. 본 연구를 통하여 단결정 ${\beta}-Ga_2O_3$의 전력반도체 활용 가능성을 확인 할 수 있었다.

• 센서학회지
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• 제14권2호
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• pp.96-100
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• 2005

The planar Schottky diodes were fabricated and modeled to probe the device applicability of the cracked GaN epitaxial layer on a (111) silicon substrate. On the unintentionally n-doped GaN grown on silicon, we deposited Ti/Al/Ni/Au as the ohmic metal and Pt as the Schottky metal. The ohmic contact achieved a minimum contact resistivity of $5.51{\times}10.5{\Omega}{\cdot}cm^{2}$ after annealing in an $N_{2}$ ambient at $700^{\circ}C$ for 30 sec. The fabricated Schottky diode exhibited the barrier height of 0.7 eV and the ideality factor was 2.4, which are significantly lower than those parameters of crack free one. But in photoresponse measurement, the diode showed the peak responsivity of 0.097 A/W at 300 nm, the cutoff at 360 nm, and UV/visible rejection ratio of about $10^{2}$. The SPICE(Simulation Program with Integrated Circuit Emphasis) simulation with a proposed model, which was composed with one Pt/GaN diode and three parasitic diodes, showed good agreement with the experiment.

• 한국결정성장학회지
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• 제7권3호
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• pp.487-493
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• 1997

SiC(4H) 결정에 Ti을 열증착하여 Ti/SiC(4H) 쇼트키(Schottky) 장벽 다이오드를 만들었다. SiC(4H)의 주개농도(donor concentration)는 전기용량-전압(C-V) 측정으로부터 $2.0{\times}10^{15}{\textrm}{cm}^{-3}$이었으며, 내부전위(built-in potential)는 0.65 V이었다. 전류-전압(I-V) 특성으로 부터 다이오드의 이상계수(ideally factor)는 1.07이었으며, 역방향 항복전장(breakdown field)은 약 $1.7{\times}10^3V/{\textrm}{cm}$이었다. 상온에서 $140^{\circ}C$까지 온도변화에 따라 측정된 포화전류로 부터 구한 전위장벽(potential barrier)은 0.91 V이었는데, 이는 C-V 특성으로 부터 구한 전위장벽과 거의 같았다.