• 대한전자공학회논문지SD
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• 제44권8호
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• pp.45-51
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• 2007

[ $1.6{\mu}m$ ]의 활성층을 가지는 planar형태의 94 GHz graded-gap injector GaAs 건 다이오드를 설계, 제작하였다. 이 다이오드는 반 절연 기판에 성장된 에피 구조를 바탕으로 메사 식각, 오믹 금속 접촉형성 및 overlay metalization의 주요 공정을 통하여 두가지 형태의 planar 구조로 제작되었다. 제작된 건 다이오드의 부성저항 특성을 anode와 cathode 금속전극들의 배치를 달리 한 두 소자 구조에서 고찰하였고 graded-gap injector의 역할을 순방향과 역방향에서의 직류거동으로부터 살펴보았다. 결과적으로, 금속전극의 배치에 있어서, cathode와 anode 전극사이의 거리가 감소된 소자 구조에서 증가된 peak 전류와 breakdown 전압, 그리고 감소된 문턱전압을 얻었다.

• 한국재료학회지
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• 제16권10호
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• pp.629-632
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• 2006

Electrical characteristics of Pt/Ti/Pt/Au and Pd/Zn/Pd/Au contacts to p-type InGaAs grown on an InP substrate have been characterized as a function of the doping concentration and the annealing temperature. The Pt/Ti/Pt/Au contacts produced the specific contact resistance as low as $2.3{\times}10^{-6}{\Omega}{\cdot}cm^2$, when heat-treated at an annealing temperature of $400^{\circ}C$. Comparison of the Pt/Ti/Pt/Au and Ti/Pt/Au contacts showed that the first Pt layer plays an important role in reducing the contact resistivity probably by lowering energy barrier at the metal-semiconductor interface. For the Pd/Zn/Pd/Au contacts, the contact resistivity remained virtually unchanged with increasing annealing temperature. The specific contact resistivity as low as $4.7{\times}10^{-6}{\Omega}{\cdot}cm^2$ was obtained. The results indicate that the Pt/Ti/Pt/Au and Pd/Zn/Pd/Au schemes could be potentially important for the fabrication of InP-based optoelectronic devices, such as photodetector and optical modulator.

• 대한금속재료학회지
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• 제48권5호
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• pp.456-461
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• 2010

We investigated the In-based ohmic contacts on Nitrogen-face (N-face) n-type GaN, as well as Ga-face n-type GaN, for InGaN-based vertical Light Emitting Diodes (LEDs). For this purpose, we fabricated Circular Transfer Length Method (CTLM) patterns on the N-face n-GaN that were prepared by using a laser-lift off method, as well as on the Ga-face n-GaN that were prepared by using a dry etching method. Then, In/transparent conducting oxide (TCO) and In/TiW schemes were deposited on the CTLM in order for low resistance ohmic contacts to form. The In/TCO scheme on the Ga-face n-GaN showed high specific contact resistance, while the minimum specific contact resistance was only 3${\times}$10$^{-2}$ $\Omega$-cm$^{2}$ after annealing at 300${^{\circ}C}$, which can be attributed to the high sheet resistance of the TCO layer. In contrast, the In/TiW scheme on the Ga-face n-GaN produced low specific contact resistance of 2.1${\times}$10$^{5}$ $\Omega$-cm$^{2}$ after annealing at 500${^{\circ}C}$ for 1 min. In addition, the In/TiW scheme on the N-face n-GaN also resulted in a low specific contact resistance of 2.2${\times}$10$^{-4}$ $\Omega$-cm$^{2}$ after annealing at 300${^{\circ}C}$. These results suggest that both the Ga-face n-GaN and N-face n-GaN.