• Title, Summary, Keyword: RF power

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Technical Trends in Next-Generation GaN RF Power Devices and Integrated Circuits (차세대 GaN RF 전력증폭 소자 및 집적회로 기술 동향)

  • Lee, S.H.;Lim, J.W.;Kang, D.M.;Baek, Y.S.
    • Electronics and Telecommunications Trends
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    • v.34 no.5
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    • pp.71-80
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    • 2019
  • Gallium nitride (GaN) can be used in high-voltage, high-power-density/-power, and high-speed devices owing to its characteristics of wide bandgap, high carrier concentration, and high electron mobility/saturation velocity. In this study, we investigate the technology trends for X-/Ku-band GaN RF power devices and MMIC power amplifiers, focusing on gate-length scaling, channel structure, and power density for GaN RF power devices and output power level and output power density for GaN MMIC power amplifiers. Additionally, we review the technology trends in gallium arsenide (GaAs) RF power devices and MMIC power amplifiers and analyze the technology trends in RF power devices and MMIC power amplifiers based on both GaAs and GaN. Furthermore, we discuss the current direction of national research by examining the national and international technology trends with respect to X-/Ku-band power devices and MMIC power amplifiers.

Effect of RF Power on Structural and Electrical Properties of Ga-Doped ZnO for Transparent Electrode of Thin Film Solar Cells (박막 태양전지용 투명 전극을 위한 Ga 도핑된 ZnO의 RF 전력에 따른 구조 및 전기 특성 변화)

  • Son, Chang-Sik
    • Korean Journal of Materials Research
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    • v.21 no.4
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    • pp.202-206
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    • 2011
  • We have investigated the structural and electrical properties of Ga-doped ZnO (GZO) thin films deposited by an RF magnetron sputtering at various RF powers from 50 to 90W. All the GZO thin films are grown as a hexagonal wurtzite phase with highly c-axis preferred parameters. The structural and electrical properties are strongly related to the RF power. The grain size increases as the RF power increases since the columnar growth of GZO thin film is enhanced at an elevated RF power. This result means that the crystallinity of GZO is improved as the RF power increases. The resistivity of GZO rapidly decreases as the RF power increases up to 70 W and saturates to 90W. In contrast, the electron concentration of GZO increases as the RF power increases up to 70 W and saturates to 90W. GZO thin film shows the lowest resistivity of $2.2{\times}10^{-4}{\Omega}cm$ and the highest electron concentration of $1.7{\times}10^{21}cm^{-3}$ at 90W. The mobility of GZO increases as the RF power increases since the grain boundary scattering decreases due to the reduced density of the grain boundary at a high RF power. The transmittance of GZO thin films in the visible range is above 90%. GZO is a feasible transparent electrode for application as a transparent electrode for thin film solar cells.

Embedded RF Test Circuits: RF Power Detectors, RF Power Control Circuits, Directional Couplers, and 77-GHz Six-Port Reflectometer

  • Eisenstadt, William R.;Hur, Byul
    • Journal of information and communication convergence engineering
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    • v.11 no.1
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    • pp.56-61
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    • 2013
  • Modern integrated circuits (ICs) are becoming an integrated parts of analog, digital, and radio frequency (RF) circuits. Testing these RF circuits on a chip is an important task, not only for fabrication quality control but also for tuning RF circuit elements to fit multi-standard wireless systems. In this paper, RF test circuits suitable for embedded testing are introduced: RF power detectors, power control circuits, directional couplers, and six-port reflectometers. Various types of embedded RF power detectors are reviewed. The conventional approach and our approach for the RF power control circuits are compared. Also, embedded tunable active directional couplers are presented. Then, six-port reflectometers for embedded RF testing are introduced including a 77-GHz six-port reflectometer circuit in a 130 nm process. This circuit demonstrates successful calibrated reflection coefficient simulation results for 37 well distributed samples in a Smith chart. The details including the theory, calibration, circuit design techniques, and simulations of the 77-GHz six-port reflectometer are presented in this paper.

Design of RF Power Detector Module with Switch for W-CDMA Optic Repeater (스위치를 이용한 W-CDMA 광중계기용 RF 전력 검출기 모듈의 설계)

  • Lee, Yun-Bok;Cho, Jung-Yong;Shin, Kyung-Sub;Lee, Yong-An;Lee, Hong-Min
    • Proceedings of the Korea Electromagnetic Engineering Society Conference
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    • pp.389-393
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    • 2003
  • This paper describes the design of enhanced TSSI RF Power Detector which has wide dynamic range using switch and Log amp. This Power Detector consists of low and high gain loops, and they adaptively switched by output DC voltage which is proportioned to input power level. Because Power Detector needs to separate the channel, so architecture is heterodyne system having 70MHz intermediate frequency. This proposed RF Power Detector is settle to the satisfaction of Closed loop power control system for W-CDMA optic repeater, and the obtained dynamic range cover the higher than 50dB.

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TEM Analysis of Interfaces between Cr Film Sputtered with RE Bias and Photosensitive Polyimide (RE 바이어스 스퍼터링한 Cr 박막과 감광성 폴리이미드 사이의 계면 TEM 분석)

  • 조성수;김영호
    • Journal of the Microelectronics and Packaging Society
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    • v.10 no.2
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    • pp.39-47
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    • 2003
  • Cr thin films were deposited on photosensitive polyimide substrates by RF bias sputtering and DC sputtering and the interfaces between Cr thin film and polyimide were observed using TEM. When the polyimide surface was in-situ RF plasma cleaned at the RF power density of 0.13-2.12 $W/cm^2$, increasing of RF power density changed the morphology of polyimide surfaces from round dig to sharp shape, and surface roughness increased by anisotropic etching. The intermixed layer-like interfaces between Cr and polyimide were observed in the RF bias sputtered specimens. This interface seems to be formed due to the RF cleaning effect; the polyimide surface was RF plasma cleaned while RF power was increased to the setting point before Cr deposition.

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SiON/SiO2 Multilayer Deposited by PECVD for Low-Loss Waveguides (저손실 광도파로 제작을 위해 PECVD 법에 의해 증착된 SiON/SiO2 다층박막)

  • 김용탁;김동신;윤대호
    • Journal of the Korean Ceramic Society
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    • v.41 no.3
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    • pp.197-201
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    • 2004
  • SiO$_2$ and SiON thick films were deposited by Plasma Enhanced Chemical Vapor Deposition (PECVD) technique on silicon wafer (100) using SiH$_4$ and $N_2$O as precursor gases. In this work, the influence of rf power, and rf bias power on the optical and physical properties of SiO$_2$ and SiON thick films is presented. The refractive index decreases with increasing rf power, and rf bias power. The refractive index of the films varied from 1.4493 to 1.4952 at wavelength at 1552 nm, with increasing rf power, the nitrogen content decreases while the oxygen content increases, in a manner that the O/N ratio increases approximately linearly.

Reliability Evaluation of RF Power Amplifier for Wireless Transmitter

  • Choi, Jin-Ho
    • Journal of information and communication convergence engineering
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    • v.6 no.2
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    • pp.154-157
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    • 2008
  • A class-E RF(Radio Frequency) power amplifier for wireless application is designed using standard CMOS technology. To drive the class-E power amplifier, a class-F RF power amplifier is used and the reliability characteristics are studied with a class-E load network. The reliability characteristic is improved when a finite-DC feed inductor is used instead of an RF choke with the load. After one year of operating, when the load is an RF choke the output current and voltage of the power amplifier decrease about 17% compared to initial values. But when the load is a finite DC-feed inductor the output current and voltage decrease 9.7%. The S-parameter such as input reflection coefficient(S11) and the forward transmission scattering parameter(S21) is simulated with the stress time. In a finite DC-feed inductor the characteristics of S-parameter are changed slightly compared to an RF-choke inductor. From the simulation results, the class-E power amplifier with a finite DC-feed inductor shows superior reliability characteristics compared to power amplifier using an RF choke.

Effect of RF Power on the Structural, Optical and Electrical Properties of Amorphous InGaZnO Thin Films Prepared by RF Magnetron Sputtering (RF 마그네트론 스퍼터링으로 증착한 비정질 InGaZnO 박막의 구조적, 광학적, 전기적 특성에 미치는 RF 파워의 영향)

  • Shin, Ji-Hoon;Cho, Young-Je;Choi, Duck-Kyun
    • Korean Journal of Metals and Materials
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    • v.47 no.1
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    • pp.38-43
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    • 2009
  • To investigate the effect of RF power on the structural, optical and electrical properties of amorphous InGaZnO (a-IGZO), its thin films and TFTs were prepared by RF magnetron sputtering method with different RF power conditions of 40, 80 and 120 W at room temperature. In this study, as RF power during the deposition process increases, the RMS roughness of a-IGZO films increased from 0.26 nm to 1.09 nm, while the optical band-gap decreased from 3.28 eV to 3.04 eV. In the case of the electrical characteristics of a-IGZO TFTs, the saturation mobility increased from $7.3cm^2/Vs$ to $17.0cm^2/Vs$, but the threshold voltage decreased from 5.9 V to 3.9 V with increasing RF power. It is regarded that the increment of RF power increases the carrier concentration of the a-IGZO semiconductor layer due to the higher generation of oxygen vacancies.

Properties of ZnO:Ga thin films deposited by RF magnetron sputtering under various RF power

  • Kim, Deok Kyu;Kim, Hong Bae
    • Applied Science and Convergence Technology
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    • v.24 no.6
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    • pp.242-244
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    • 2015
  • ZnO:Ga thin films were deposited by RF magnetron sputtering technique from ZnO (3 wt.% $Ga_2O_3$) target onto glass substrates under various RF power. The influence of RF power on the structural, electrical, and optical properties of ZnO:Ga thin films was investigated by X-ray diffraction, atomic force microscopy, Hall method and optical transmission spectroscopy. As the RF power increases from 50 to 110W, the crystallinity is deteriorated, the root main square surface roughness is decreased and the sheet resistance is increased. The increase of sheet resistance is caused by decreasing carrier concentration due to interstitial Ga ion. All films are transparent up to 80% in the visible wavelength range and the adsorption edge is a red-shift with increasing RF power.

The Structures, Optical and Electrical Properties of IGZO Thin Films by RF Magnetron Sputtering According to RF Power (RF magnetron sputtering으로 증착한 IGZO 박막의 RF power에 따른 구조적, 광학적 및 전기적 특성 연구)

  • Yeon, Je ho;Kim, Hong Bae
    • Journal of the Semiconductor & Display Technology
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    • v.15 no.3
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    • pp.57-61
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    • 2016
  • We have studied the structural, optical and electrical properties of IGZO thin films. The IGZO thin films were deposited on the silicon wafer by RF magnetron sputtering method. The RF power in sputtering process was varied as 15W, 30W, 45W, 60W, 75W, respectively. All of the thin films transmittance in the visible range was above 85%. XRD analysis showed that amorphous structure of the thin films without any peak. The Hall measurements in the low RF power is the high mobility above $10cm^2/V{\cdot}s$ and the low resistvity are obtained in the IGZO thin films.