http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Trench‐type deep N‐well dual guard ring for the suppression of substrate noise coupling
Oh, Yongho,Lee, Seungyong,Shin, Hyungcheol,Rieh, Jae‐,Sung Wiley Subscription Services, Inc., A Wiley Company 2011 International journal of RF and microwave computer Vol.21 No.1
<P><B>Abstract</B></P><P>This article presents a study on the isolation performance of the trench‐type deep n‐well (DNW) dual guard ring (GR) and its effect on the suppression of the substrate digital noise coupling on a low noise amplifier (LNA) based on measurement and TCAD simulation. The trench‐type DNW dual GR, in which the DNW is formed beneath the ring‐shaped n‐well region only, can be adopted for protecting the noise‐sensitive analog/RF circuits or circuit blocks against the substrate noise. An in‐depth analysis on the performance of the trench‐type DNW was carried out based on both measurement and a heavy use of TCAD. The results show that the trench‐type DNW dual GR exhibits comparable isolation to that of the pocket‐type DNW dual GR at high frequency regime. The effect of various GR dimension parameters and GR bias conditions on the GR isolation performance was also investigated and analyzed. Furthermore, the trench‐type DNW dual GR was applied to a 5.8‐GHz LNA and its effect on the suppression of the substrate digital noise coupling was studied for various digital noise conditions and GR bias schemes. © 2010 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2011.</P>
Yongho Oh,Jae-Sung Rieh IEEE 2011 IEEE transactions on microwave theory and techniqu Vol.59 No.6
<P>This paper presents a comprehensive study on the high-Q island-gate varactor (IGV), which includes a comparison with the conventional multifinger varactors (MFVs) and analyses on the effect of structural variations on the varactor performance. The study shows that the IGV exhibits smaller R(s) and larger Q factor compared to the MFV, while its capacitance tuning ratio is smaller. The effect of the dimension variation and shape of the gate island, as well as the gate thickness, is substantial and the observed trends can be exploited for IGV optimization. This work indicates that the IGV is a highly promising option for millimeter-wave applications.</P>
Gate Workfunction Optimization of a 32 ㎚ Metal Gate MOSFET for Low Power Applications
Yongho Oh,Youngmin Kim 대한전기학회 2006 Journal of Electrical Engineering & Technology Vol.1 No.2
The feasibility of a midgap metal gate is investigated for a 32 ㎚ MOSFET for low power applications. The midgap metal gate MOSFET is found to deliver Ion as high as a bandedge gate if a proper retrograde channel is used. An adequate design of the retrograde channel is essential to achieve the performance requirement given in the ITRS roadmap. A process simulation is also run to evaluate the feasibility of the necessary retrograde profile in manufacturing environments. Based on the simulated result, it is found that any subsequent thermal process should be tightly controlled to retain transistor performance, which is achieved using the retrograde doping profile. Also, the bandedge gate MOSFET is determined be more vulnerable to the subsequent thermal processes than the midgap gate MOSFET. A guideline for gate workfunction (Фm) is suggested for the 32 ㎚ MOSFET.
Gate Workfunction Optimization of a 32 nm Metal Gate MOSFET for Low Power Applications
Yongho Oh,김영민 대한전기학회 2006 Journal of Electrical Engineering & Technology Vol.1 No.2
- The feasibility of a midgap metal gate is investigated for a 32 nm MOSFET for low powerapplications. The midgap metal gate MOSFET is found to deliver Ion as high as a bandedge gate if a the performance requirement given in the ITRS roadmap. A process simulation is also run to evaluate the feasibility of the necessary retrograde profile in manufacturing environments. Based on the simulated result, it is found that any subsequent thermal process should be tightly controlled to retain transistor performance, which is achieved using the retrograde doping profile. Also, the bandedge gate MOSFET is determined be more vulnerable to the subsequent thermal processes than the midgap gate MOSFET. A guideline for gate workfunction (Фm) is sugested for the 32 nm MOSFET. .
The Island-Gate Varactor—A High-Q MOS Varactor for Millimeter-Wave Applications
Yongho Oh,Sooyeon Kim,Seungyong Lee,Jae-Sung Rieh IEEE 2009 IEEE microwave and wireless components letters Vol.19 No.4
<P>A new accumulation MOS varactor with island-shaped poly gate layout is proposed to improve the quality factor ( Q-factor) at high frequency, which can be readily employed for CMOS-based millimeter-wave applications. Measured results up to 67 GHz show significant improvements in the Q-factor and the series resistance R<SUB>s</SUB> over the conventional multi-finger MOS varactors with the same ground rule and gate area. The proposed island-gate MOS varactor is expected to improve the overall Q-factor of the LC tank of millimeter-wave oscillators.</P>
Impact of Substrate Digital Noise Coupling on the High-Frequency Noise Performance of RF MOSFETs
Yongho Oh,Seungyong Lee,Chan Hyeong Park,Jae-Sung Rieh IEEE 2009 IEEE microwave and wireless components letters Vol.19 No.9
<P>The impact of digital noise coupling through the substrate on RF MOSFETs was investigated in terms of the noise figure (NF) of the device up to 26.5 GHz. Previous works on the substrate digital noise coupling have treated the effect mostly in terms of the electrical isolation between ports, rather than actual devices, which does not provide direct information on the degradation of actual device performance parameters from such coupling. In this work, an actual NMOSFET was employed for test and the effect was described in terms of NF, a practical device performance parameter. The results show that NF is significantly degraded as the device enters the weak inversion state and/or <I>V</I> <SUB>ds</SUB> becomes smaller, suggesting a trade-off between low power operation and immunity against the substrate noise coupling. Also, it is experimentally verified that devices with a dual guard ring showed much smaller NF than those with a single guard ring.</P>
Variation in RF Performance of MOSFETs Due to Substrate Digital Noise Coupling
Yongho Oh,Sanggeun Jeon,Jae-Sung Rieh IEEE 2010 IEEE microwave and wireless components letters Vol.20 No.7
<P>In this letter, the variation in the key RF performance parameters of MOSFETs in the presence of the substrate digital noise coupling is investigated. The parameters, including f<SUB>T</SUB> and f<SUB>max</SUB>, showed substantial change up to ~20% with realistic level of noise injection. It is shown that such change in the RF performance with the noise injection is due to the threshold voltage ( V<SUB>T</SUB>) variation. The observed V<SUB>T</SUB> variation is attributed to the virtual body effect due to the substrate potential fluctuation by the coupled substrate digital noise.</P>
Effect of Device Layout on the Stability of RF MOSFETs
Yongho Oh,Jae-Sung Rieh IEEE 2013 IEEE transactions on microwave theory and techniqu Vol.61 No.5
<P>In this paper, the stability of RF MOSFETs is investigated in terms of the stability-factor (<I>k</I> -factor) for various layout schemes and device dimensions based on two different RFCMOS technologies. To systematically analyze the effect of small-signal device model parameters on RF MOSFET stability, the expression for <I>k</I>-factor is derived as a function of the small-signal model parameters of RF MOSFETs. Based on the expression, the effect of small-signal model parameters on the stability of RF MOSFETs is explored along with its bias dependence. In addition, the effect of wiring schemes, number of gate fingers, gate finger pitch, and gate length is examined based on various device structures. It is shown that the transconductance and capacitances are the dominant device parameters to determine the stability of RF MOSFETs. The result also indicates that the stability of RF MOSFETs is strongly affected by the details of layout scheme and lateral dimension. Additionally, it was found that there is a tradeoff between device stability and speed. This study is expected to serve a guideline for the device design and optimization for stable operation of RF MOSFETs and circuits based on them.</P>