• Journal of the Korean Vacuum Society
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• v.22 no.1
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• pp.31-36
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• 2013

For the simplification of doping process in amorphous carbon film, arsenic (As) ions were implanted on the nucleated silicon wafer before the growth process. Then amorphous carbon films were grown at the condition of $CH_4/H_2=5%$ by microwave plasma chemical vapour deposition. Because the implanted seeds were grown at the high temperature and the implanted ions were spread, it was possible to reduce the process steps by leaving out the annealing process. When the implanted amorphous carbon films were electrically characterized in diode configuration, field emission current of $0.1mA/cm^2$ was obtained at the applied electric field of about $2.5V/{\mu}m$. The results show that the implanted As ions were sufficiently doped by the self-annealing process by using the growth after implantation.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.6 no.1
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• pp.37-47
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• 1995

In this paper, the slot coupled stacked microstrip antenna, which has wide bandwidth characteristics because of the double tuning effects from the interactions between two patches and feeding slot and improves distortions of radiation patterns due to spurious radiation from feeder, is analyzed. For the analy- sis Green function in the spectrum domain and Galerkin method is applied with an accurate analysis mode for slot coupled feeding structure using the scattering analysis method. The basis functions are 3 EB modes for patches and 5 PWS modes for feeder. The slot coupled stacked microstrip antennas are designed and fabricated with the center frequency of 11.5 Ghz and 12.0 GHz. The experimental results show the wide bandwidth characteristics of 1.9 ~ 2.2 GHz and agree well with the simulation results which have 15~20% bandwidth.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.200-200
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• 2010

열영상의 해상도 증가 시 야기되는 감도저하를 해결하고자 단위 픽셀의 크기를 줄이고 필팩터 향상을 위한 2앵커, 4앵커 구조를 제안하고 앵커 구조에서 Leg 구성물질의 두께변화에 따른 온도 변화 및 열전도도 특성을 실험을 통해 최적화 된 열영상을 구현한다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.1
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• pp.12-18
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• 2002

In this paper a novel dielectric resonator (DR) bandpass filter (BPF) with flexible arrangement of attenuation poles is proposed. This DR filter is similar to a conventional DR filter except adding a microstrip line below a DR, which not only shifts the location of attenuation poles, but also improves skirt characteristics. The duplexer with the proposed DR BPF has been yielded better isolation and sharper skirt behavior than that with a conventional DR filter. The implemented duplexer has shown a good performance and been well agreed with the simulation.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.21 no.3
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• pp.110-113
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• 2011

In this paper, we propose a new method for the fabrication of GaN microstructures formed only on the vertex of GaN pyramid by using of metal catalysts. GaN pyramidal structures were selectively grown on 3 ${\mu}m$ $SiO_2$ dot patterns followed by thin film deposition of Au and Cr only on the vertex area of the GaN pyramids with precisely controlled photolithography. After the metal deposition, the samples were loaded in the MOVPE reactor for the growth of GaN microstructures for 10 minutes. Temperature for the growth of the GaN microstructures was changed from $650^{\circ}C$ to $750^{\circ}C$. Rod type GaN microstructures were grown in the direction of vertical to the six {1-101} facets and the shape of the GaN microstructures was changed depend on the type of metal.

• Korean Journal of Optics and Photonics
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• v.16 no.5
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• pp.469-475
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• 2005

An integrated photonic microwave bandpass filter has been proposed and demonstrated incorporating a coherently coupled microring resonator in low-loss polymers. The proposed device may feature compact site, simple structure, tuning via the thermooptic and electrooptic effect, and flexible integration with other electrical and optical devices. The resonator was designed to have an extremely small bandwidth so that it could be used to selectively pass the optical signal carrying the microwave signal to attain efficient bandpass filtering. We made and tested two resonators with a single ring and double rings, and performed a theoretical fitting of their measured transfer curves to predict the performance of the microwave filters based on them precisely. It was found that as the number of the rings used for the resonator increases, the bandwidth gets smaller, the rolloff sharper, and the band rejection higher. Finally our filter exhibited the center frequency of 10GHz, the 3-dB bandwidth of 1.0GHz, the corresponding quality (Q) factor of 10, and the rejection outside of the passband of more than 25dB.

• Journal of Sensor Science and Technology
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• v.10 no.1
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• pp.1-8
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• 2001

Conventional microgyroscopes of vibrating type require resonant frequency tuning of the driving and sensing modes to achieve high sensitivity. These tuning conditions depend on each fabricated microgyroscopes, even though the microgyroscopes are identically designed. A new micromachined resonator, which is applicable to microgyroscopes with self-toning characteristics, is presented. Since the laterally driven two degrees of freedom (2DOF) resonator was designed as a symmetric structure with identical stiffness in two orthogonal axes, the resonator is applicable to vibrating microgyroscopes, which do not need mode tuning. A dynamic model of the resonator was derived considering gyroscopic application. The dynamic model was evaluated by experimental comparison with fabricated resonators. The microgyroscopes were fabricated using a simple 2-mask-process of a single polysilicon layer deposited on an insulator layer. The feasibility of the resonator as a vibrating microgyroscopes with self-tuning capability is discussed. The fabricated resonators of a particular design have process-induced non-uniformities that cause different resonant frequencies. For several resonators, the standard deviations of the driving and sensing frequencies were as high as 1232Hz and 1214Hz, whereas the experimental average detuning frequency was 91.75Hz. The minimum detuned frequency was 68Hz with $0.034mVsec/^{\circ}$ sensitivity. The sensitivity of the microgyroscopes was low due to process-induced non-uniformity; the angular rate bandwidth, however, was wide. This resonator could be successfully applicable to a vibrating microgyroscopes with high sensitivity, if improvements in uniformity of the fabrication process are achieved. Further developments in improved integrated circuits are expected to lower the noise level even more.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2001.07a
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• pp.100-103
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• 2001

In this study, the adhesion and thermal property of the electroless-deposited Cu thin film were investigated. The multilayered structure of Cu/TaN/Si was fabricated by electroless-depositing the Cu thin layer on the TaN diffusion barrier which was deposited by MOCVD on the Si substrate. The thermal stability was investigated by measuring the resistivity as post-annealing temperature far the multilayered Cu/TaN/Si specimen which was annealed at Ar gas. The adhesion property of Cu 171ms was evaluated by the scratch test. The adhesion of the electroless-deposited Cu film was compared with other deposition methods of thermal evaporation and sputtering. The scratch test showed that the adhesion of electroless plated Cu film on TaN was better than those of sputtered Cu film and evaporated Cu film.

• Journal of the Microelectronics and Packaging Society
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• v.9 no.2
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• pp.33-38
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• 2002

High performance packages must have a minimum insertion loss and return loss. In this paper, we design a millimeter-wave ceramic package using LTCC (Low Temperature Cofired Ceramic) technology to satisfy excellent transmission characteristics and characterize in a frequency range from DC to 30 GHz using the FEM (Finite Element Method) calculation. From these calculation results, the designed feed-through structure achieved 0.32 dB, 16.8 dB of the insertion loss and the return loss at 30 GHz respectively. This designed ceramic package will be useful for MMIC (Monolithic Microwave Integrated Circuit) modules.

• Journal of the Microelectronics and Packaging Society
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• v.12 no.1 s.34
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• pp.59-63
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• 2005

A simulation method combined with the simulation program with integrated circuit emphasis (SPICE) and the technology computer-aided design (TCAD) has been proposed to estimate the electrical characteristics of the metal-ferroelectric-semiconductor field effect transistor (MFS/MFISFET). The complex behavior of the ferroelectric property was analyzed and surface potential of the channel region in the MFS gate structure was calculated with the numerical TCAD method. Since the calculated surface potential is equivalent with the surface potential obtained with the SPICE model of the conventional MOSFET, we can obtain the current-voltage characteristics of MFS/MFISFET corresponding to the applied gate bias. Therefore, the proposed method will be very useful for the design of the integrated circuits with MFS/MFISFET memory cell devices.