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Optimized phase noise of LC VCO using an asymmetric-inductance tank in InGaP/GaAs HBT technology
Yoon, Jae-Ho,Lee, Sang-Hun,Koh, Ah-Rah,Kennedy, Gary P.,Kim, Nam-Young Wiley Subscription Services, Inc., A Wiley Company 2006 MICROWAVE AND OPTICAL TECHNOLOGY LETTERS - Vol.48 No.6
<P>This paper describes fully integrated low-phase-noise MMIC voltage-controlled oscillators (VCOs) for an adaptive-feedback interference-cancellation system (AF-ICS). The asymmetric- and symmetric-inductance tank structures were combined with VCOs to obtain VCOs with low-phase-noise performance. The asymmetric-inductance tank VCO (AIT-VCO) has a tuning range of 261 MHz with an output power of −11.53 dBm at 1.715 GHz. Furthermore, the phase noise of this VCO is −117.3 dBc/Hz and −129.3 dBc/Hz at 100-kHz and 1-MHz offset frequencies, respectively. The symmetric-inductance tank VCO (SIT-VCO) has a tuning range of 160 MHz with an output power of −15 dBm at 1.664 GHz. Furthermore, the phase noise of this VCO is −102.4 dBc/Hz and −121.9 dBc/Hz at 100-kHz and 1-MHz offset frequencies, respectively. Each of these VCOs occupies a total chip area of 0.9 × 0.9 mm<SUP>2</SUP>. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1035–1040, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21593</P>
Chun, Sung-Yong,Im, Hyun-Ho The Korean Ceramic Society 2017 한국세라믹학회지 Vol.54 No.1
Single phase niobium nitride (NbN) coatings were deposited using asymmetric bipolar pulsed dc sputtering by varying pulse frequency and duty cycle of pulsed plasmas. Crystal structure, microstructure, morphology and mechanical properties were examined using XRD, FE-SEM, AFM and nanoindentation. Upon increasing pulse frequencies and decreasing duty cycles, the coating morphology was changed from a pyramidal-shaped columnar structure to a round-shaped dense structure with finer grains. Asymmetric bipolar pulsed dc sputtered NbN coatings deposited at pulse frequency of 25 kHz is characterized by higher hardness up to 17.4 GPa, elastic modulus up to 193.9 GPa, residual compressive stress and a smaller grain size down to 27.5 nm compared with dc sputtered NbN coatings at pulse frequency of 0 kHz. The results suggest that the asymmetric bipolar pulsed dc sputtering technique is very beneficial to reactive deposition of transition-metal nitrides such as NbN coatings.
비대칭 바이폴라 펄스 스퍼터법으로 증착된 VN 코팅막의 미세구조, 결정구조 및 기계적 특성에 관한 연구
전성용(Sung-Yong Chun),정평근(Pyeong-Geun Jeong) 한국표면공학회 2016 한국표면공학회지 Vol.49 No.5
Nanocrystalline vanadium nitride (VN) coatings were deposited using asymmetric bipolar pulsed dc sputtering to further understand the influence of the pulsed plasmas on the crystal structure, microstructure and mechanical properties. Properties of VN coatings were investigated with FE-SEM, XRD and nanoindentation. The results show that, with the increasing pulse frequency and decreasing duty cycle, the coating morphology changed from a porous columnar to a dense structure, with finer grains. Asymmetric bipolar pulsed dc sputtered VN coatings showed higher hardness, elastic modulus and residual compressive stress than dc sputtered VN coatings. The results suggest that asymmetric bipolar pulsed dc sputtering technique is very beneficial for the reactive sputtering deposition of VN coatings.
DC 스퍼터법과 비대칭 바이폴라 펄스 DC 스퍼터법으로 증착된 TiN 코팅막의 물성 비교연구
전성용(Sung-Yong Chun) 한국표면공학회 2011 한국표면공학회지 Vol.44 No.5
This work investigated the effect of duty cycle and pulse frequency on the microstructures and properties of titanium nitride thin films deposited by asymmetric bipolar pulsed DC sputtering system. Oscilloscope traces of the I-V waveforms indicate high power and high current density outputs during the asymmetric bipolar pulsed mode. The grain size decreases with decreasing duty cycle. The duty cycle has a strong influence not only on the microstructural properties but also on the mechanical properties of titanium nitride films. Comparing with the continuous DC sputtering, the titanium nitride films prepared by pulsed DC asymmetric bipolar process exhibit better properties.
듀티 싸이클 및 펄스 주파수가 TiAlN 코팅막의 미세구조와 기계적 특성에 미치는 영향에 관한 연구
전성용,황주연,Chun, Sung-Yong,Hwang, Ju Yeon 한국세라믹학회 2014 한국세라믹학회지 Vol.51 No.5
This paper presents the effects of pulse plasma parameters such as duty cycle and pulse frequency on the properties of TiAlN coatings deposited by asymmetric bipolar pulsed DC magnetron sputtering systems. The results show that, with decreasing duty cycle and increasing pulse frequency, the coating morphology changes from a columnar structure to a dense structure with finer grains. Pulsed sputtered TiAlN coatings showed higher hardness, higher residual stress, and smaller grain sizes than did DC prepared TiAlN coatings. Moreover, residual stress and nanoindentation hardness of pulsed sputtered TiAlN coatings increased with increasing pulse frequency. Meanwhile, the surface roughness decreased continuously with increasing pulsed DC frequency up to 50 kHz.
비대칭 펄스 DC 반응성 마그네트론 스퍼터링으로 증착된 나노결정질 TiN 박막의 성장거동
한만근,전성용 한국세라믹학회 2011 한국세라믹학회지 Vol.48 No.5
Nanocrystalline TiN films were deposited on Si(100) substrate using asymmetric pulsed DC reactive magnetron sputtering. We investigated the growing behavior and the structural properties of TiN films with change of duty cycle and pulsed frequency. Grain size of TiN films were decreased from 87.2 nm to 9.8 nm with decrease of duty cycle. The 2θ values for (111) and (200) crystallographic planes of the TiN films were also decreased with decrease of duty cycle. This shift in 2θ could be attributed to compressive stress in the TiN coatings. Thus, the change of plasma parameter has a strong influence not only on the microstructure but also on the residual stresses of TiN films.
DC 스퍼터법과 비대칭 양극성 펄스 스퍼터법으로 제작된 고분자 전해질 연료전지 금속분리판용 CrN 코팅막의 특성 연구
박상원,전성용,Park, Sang-Won,Chun, Sung-Yong 한국세라믹학회 2013 한국세라믹학회지 Vol.50 No.6
Nanocrystalline CrN films were deposited on Si (100) substrates by means of asymmetric pulsed DC reactive magnetron sputtering. We investigated the growth behavior, corrosion resistance and mechanical properties of CrN films with a change in the duty cycle and pulse frequency. The grain size of the CrN films decreased from 25.4 nm to 11.2 nm upon a decrease in the duty cycle. The corrosion potentials for the CrN films by DC sputtering was approximately - 0.6 V, and it increased to - 0.3 V in the CrN films which underwent pulsed sputtering. The nanoindentation hardness of the CrN films also increased with a decrease in the duty cycle. This enhancement of the corrosion resistance and mechanical properties of pulsed sputtered CrN films could be attributed to the densification and surface smoothness of the microstructure of the films.
DC 스퍼터법과 비대칭 바이폴라 펄스 DC 스퍼터법으로 증착된 TiAlN 코팅막의 물성 비교연구
전성용(Sung-Yong Chun),이태양(Tae Yang Lee) 한국표면공학회 2014 한국표면공학회지 Vol.47 No.4
The paper presents the comparative results of TiAlN coatings deposited by DC and pulsed DC asymmetric bipolar magnetron sputtering systems. The results show that, with the decreasing duty cycle and increasing pulse frequency, the coating morphology changes from a columnar to a dense structure, with finer grains. Pulsed sputtered TiAlN coatings showed higher hardness, higher residual stress, and smaller grain sizes than dc prepared TiAlN coatings. Moreover residual stress of pulsed sputtered TiAlN coatings increased on increasing pulse frequency. Meanwhile, the surface roughness decreased continuously with increasing pulsed DC frequency up to 50 kHz.
DC 스퍼터법과 비대칭 바이폴라 펄스 DC 스퍼터법으로 증착된 NbN 코팅막의 물성 비교연구
전성용(Sung-Yong Chun),오복현(Bok-Hyun Oh) 한국표면공학회 2015 한국표면공학회지 Vol.48 No.4
The paper presents the comparative results of NbN coatings deposited by DC and pulsed DC asymmetric bipolar magnetron sputtering systems. The results show that, with the decreasing duty cycle and increasing pulse frequency, the coating morphology changes from a columnar to a dense structure, with finer grains. The Pulsed sputtered NbN coatings showed higher hardness, higher residual stress, and smaller grain sizes than those of DC prepared NbN coatings. Moreover residual stress of pulsed sputtered NbN coatings increased on increasing pulse frequency. Meanwhile, the surface roughness decreased continuously with increasing pulsed DC frequency up to 50 kHz.