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Jung S.-M.,Yonsei University | Won Y.-Y.,Yonsei Institute of Convergence Technology | Han S.-K.,Yonsei University
International Conference on ICT Convergence | Year: 2013

We propose a technique to reduce the OBI noise in OFDMA-PON link. A self-homodyne balanced detection can improve the SNR of DMT signal as well as reduce OBI noise with the help of local laser. © 2013 IEEE. Source

Lee S.,Yonsei University | Ju D.Y.,Yonsei Institute of Convergence Technology
IEEE ISI 2013 - 2013 IEEE International Conference on Intelligence and Security Informatics: Big Data, Emergent Threats, and Decision-Making in Security Informatics | Year: 2013

Smartphone OS, such as Android, enables us to install third party applications. However, security threats of malicious applications are rapidly increasing due to the nature of the third party applications where only developers can assign required permissions. For this reason, attackers can inject exploits into a normal application with inappropriately acquired permissions. In this paper, we propose a method to distinguish an application by analyzing permissions set and enhanced user interfaces to improve the chance of making right decisions. The proposed methods are intended for users to make better decisions with more information provided by the system. © 2013 IEEE. Source

Yoon S.,Yonsei Institute of Convergence Technology | Bang J.,Yonsei Institute of Convergence Technology | Song Y.,Yonsei Institute of Convergence Technology | Oh J.,Yonsei University
Thin Solid Films | Year: 2015

A complementary metal-oxide semiconductor (CMOS)-compatible Au-free Si/Ti/Al/Cu ohmic metallization scheme has been developed for AlGaN/GaN power transistors epitaxially grown on Si substrates. The Si/Ti/Al/Cu metallization exhibited a low specific contact resistance of 3.5 × 10- 6 ω cm2 after optimizing the Si interface layer. The ohmic metal surface was smooth with a root-mean-square roughness of 24 nm. Physical characterization confirmed that Cu diffusion into the semiconductor was suppressed because locally segregated TiSix alloys acted as a barrier. Shallow interfacial reactions of localized TiN alloys occurred in the AlGaN/GaN heterostructure. Without a designated diffusion barrier as in conventional Au-based metallization, the contact resistivity and surface morphology in Si/Ti/Al/Cu improved significantly, which helps address critical challenges associated with the fabrication of AlGaN/GaN power transistors on a Si CMOS platform. © 2015 Elsevier B.V. Source

Cho A.-J.,Yonsei University | Cho A.-J.,Yonsei Institute of Convergence Technology | Park K.C.,Konkuk University | Kwon J.-Y.,Yonsei University | Kwon J.-Y.,Yonsei Institute of Convergence Technology
Nanoscale Research Letters | Year: 2015

For several years, graphene has been the focus of much attention due to its peculiar characteristics, and it is now considered to be a representative 2-dimensional (2D) material. Even though many research groups have studied on the graphene, its intrinsic nature of a zero band-gap, limits its use in practical applications, particularly in logic circuits. Recently, transition metal dichalcogenides (TMDs), which are another type of 2D material, have drawn attention due to the advantage of having a sizable band-gap and a high mobility. Here, we report on the design of a complementary inverter, one of the most basic logic elements, which is based on a MoS2 n-type transistor and a WSe2 p-type transistor. The advantages provided by the complementary metal-oxide-semiconductor (CMOS) configuration and the high-performance TMD channels allow us to fabricate a TMD complementary inverter that has a high-gain of 13.7. This work demonstrates the operation of the MoS2 n-FET and WSe2 p-FET on the same substrate, and the electrical performance of the CMOS inverter, which is based on a different driving current, is also measured. © 2015, Cho et al.; licensee Springer. Source

Yoon S.,Yonsei University | Yoon S.,Yonsei Institute of Convergence Technology | Song Y.,Yonsei University | Song Y.,Yonsei Institute of Convergence Technology | And 5 more authors.
Semiconductor Science and Technology | Year: 2016

Microstructural changes in Si/Ti/Al/Cu (10/40/60/50 nm) Ohmic contacts to AlGaN/GaN heterostructure were investigated for complementary metal-oxide semiconductor compatible processes. Si/Ti/Al/Cu metallization exhibited a low specific contact resistance of 3.6 × 10-6 Ω-cm2 and contact resistance of 0.46 Ω-mm when a Si interfacial layer was used. Without a designated barrier metal, TiSix alloys that formed in the metallic region effectively suppressed Cu diffusion. The shallow TiN junction in AlGaN/GaN was attributed to TiSix in the metallic regions. Microstructural changes were detected by systematic physical characterization. © 2016 IOP Publishing Ltd. Source

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