| 1. |
- Li, Junjie, et al.
(author)
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A Novel Dry Selective Isotropic Atomic Layer Etching of SiGe for Manufacturing Vertical Nanowire Array with Diameter Less than 20 nm
- 2020
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In: Materials. - : MDPI AG. - 1996-1944. ; 13:3
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Journal article (peer-reviewed)abstract
- Semiconductor nanowires have great application prospects in field effect transistors and sensors. In this study, the process and challenges of manufacturing vertical SiGe/Si nanowire array by using the conventional lithography and novel dry atomic layer etching technology. The final results demonstrate that vertical nanowires with a diameter less than 20 nm can be obtained. The diameter of nanowires is adjustable with an accuracy error less than 0.3 nm. This technology provides a new way for advanced 3D transistors and sensors.
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| 2. |
- Wang, Guilei, et al.
(author)
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Growth of SiGe layers in source and drain regions for 10 nm node complementary metal-oxide semiconductor (CMOS)
- 2020
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In: Journal of materials science. Materials in electronics. - : Springer Science and Business Media LLC. - 0957-4522 .- 1573-482X. ; 31, s. 26-33
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Journal article (peer-reviewed)abstract
- In this study, the integration of Si 1−x Ge x (50% ≤ x ≤ 60%) selective epitaxy on source/drain regions in 10 nm node FinFET has been presented. One of the major process issues was the sensitivity of Si-fins’ shape to ex- and in-situ cleaning prior to epitaxy. For example, the sharpness of Si-fins could easily be damaged during the wafer washing. The results showed that a DHF dip before the normal cleaning, was essential to clean the Si-fins while in-situ annealing in range of 780–800 °C was needed to remove the native oxide for high epitaxial quality. Because of smallness of fins, the induced strain by SiGe could not be directly measured by X-ray beam in a typical XRD tool in the lab or even in a Synchrotron facility. Further analysis using nano-beam diffraction technique in high-resolution transmission electron microscope also failed to provide information about strain in the FinFET structure. Therefore, the induced strain by SiGe was simulated by technology computer-aided design program and the Ge content was measured by using energy dispersive spectroscopy. Simulation results showed 0.8, 1 and 1.3 GPa for Ge content of 40%, 50% and 60%, respectively. A kinetic gas model was also introduced to predict the SiGe profile on Si-fins with sharp triangular shape. The input parameters in the model includes growth temperature, partial pressure of the reactant gases and the exposed Si coverage in the chip area.
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| 3. |
- Wang, Xinchen, et al.
(author)
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Design of High-Data-Density Chipless RFID Tag Embedded in QR Code
- 2022
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In: IEEE Transactions on Antennas and Propagation. - 0018-926X .- 1558-2221. ; 70:3, s. 2189-2198
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Journal article (peer-reviewed)abstract
- A design scheme for embedding a chipless radio frequency identification (RFID) tag in a quick response (QR) code is proposed and demonstrated. By searching for QR modules that can be metalized to form a loop resonator in the edge area and to load the loop in the central area, the chipless RFID tag with an optimized loaded-loop resonator can be designed in the QR code. A specific loop genetic operator is proposed for optimization searching. The optimized loaded-loop resonator has a sharp dominant resonant peak at frequency as low as possible and a harmonic resonant peak at frequency as high as possible, which provides large space for data encoding of chipless RFID. By removing or demetalizing the metalized loading modules, the resonant frequency can be tuned conveniently for frequency shift keying (FSK) coding. For demonstration, the chipless RFID tag embedded in the QR code is designed and tested. It is shown that the RFID tag allows at least nine distinct resonant frequencies for simple FSK coding, which indicates a coding capacity of 3.17 bits and a normalization coding density of approximately 501.78 bits/ $\lambda _{\mathrm {g}}^{2}$ /GHz for the chipless RFID tag embedded in the QR code.
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| 4. |
- Tao, Yonghui, et al.
(author)
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Design of Planar Directional Coupler using 2-Bit Fragment Structures
- 2021
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In: Applied Computational Electromagnetics Society Journal. - 1054-4887. ; 36:12, s. 1610-1615
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Journal article (peer-reviewed)abstract
- Automatic design of planar directional coupler can be implemented by multi-objective optimization searching for the optimal planar fragment-type structure (FTS). The 2-bit FTS description scheme may include necessary fine structures in fragments to enhance the FTS design. By coding the coupler design space on PCB in 2-bit FTS, defining the FTS design matrix, and searching for the optimal structure, directional coupler can be designed without any structure presetting or artificial intervention. The scheme is demonstrated by designing 10-dB wideband directional coupler with 2-bit FTS scheme. The designed directional couplers are fabricated and tested to show maximum directivity of 58 dB with 36% operation bandwidth.
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| 5. |
- Tao, Yonghui, et al.
(author)
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Monte carlo‐based indoor rfid positioning with dual‐antenna joint rectification
- 2021
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In: Electronics. - : MDPI AG. - 2079-9292. ; 10:13
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Journal article (peer-reviewed)abstract
- A novel Monte Carlo‐based indoor radio‐frequency identification (RFID) positioning scheme is proposed for dual‐antenna RFID systems with the cooperation of dual‐antenna joint rec-tification. By deploying reference passive RFID tags on the ground to establish an RFID tag‐based map, indoor self‐positioning of a moving platform carrying an RFID reader with two forward‐look-ing antennas can be simply implemented by looking up the positions of responded RFID tags at each time step of movement, and estimating the platform position by using the proposed Monte Carlo‐based algorithm. To improve the positioning accuracy of Monte Carlo‐based positioning, each antenna channel, with its own footprint on the ground, may rectify its position estimation by using the tag position information interrogated by the other antenna channel. The algorithm for dual-antenna rectification is proposed. The performance of the proposed Monte Carlo‐based self‐posi-tioning scheme is demonstrated by both simulation and experiment tests. Some factors in a practical indoor‐positioning system, such as the reference tag distribution pattern, reader antenna footprint size, and footprint overlap, are discussed. Some guide rules for deploying the RFID indoor‐posi-tioning system are also reported.
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| 6. |
- Yang, Dong, et al.
(author)
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Applying Industrial Wireless Sensor Networks to Welder Machine System
- 2014
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In: IPSN 2014 - Proceedings of the 13th International Symposium on Information Processing in Sensor Networks (Part of CPS Week). ; , s. Art. no. 6835794-
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Conference paper (peer-reviewed)abstract
- Despite lots of research efforts in the area of Industrial Wireless Sensor Networks (IWSNs), there is a lack of really practical IWSN implementations, deployments and in-field experiments. This demo presents the design and implementation of an IWSN for welder machine systems based on the first IWSN standard WirelessHART. The goal of this work is to find the problems and challenges from IWSN standard to implementation, and motivate other designers to explore more IWSN applications.
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| 7. |
- Yang, Dong, et al.
(author)
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Assignment of Segmented Slots Enabling Reliable Real-Time Transmission in Industrial Wireless Sensor Networks
- 2015
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In: IEEE Transactions on Industrial Electronics. - 0278-0046 .- 1557-9948. ; 62:6, s. 3966-3977
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Journal article (peer-reviewed)abstract
- Industrial wireless sensor networks (IWSNs) have the potential to contribute significantly in areas such as cable replacement, mobility, flexibility, and cost reduction. Nevertheless, the industrial environment that the IWSNs operate in is very challenging because of dust, heat, water, electromagnetic interference, and interference from other wireless devices, which make it difficult for current IWSNs to guarantee reliable real-time communication. In this paper, we present a novel method based on the segmented slot assignment, fast slot competition, and free node concept that will improve the reliability and real-time communication significantly so that more advanced applications can be enabled. The main purpose of the algorithms is to improve the retransmission efficiency for time-division-multiple-access-based multihop IWSNs by using limited shared slot resources more efficiently. More importantly, the proposed algorithms support efficient slot rescheduling caused by link or node failure. We evaluate the proposed methods by using simulations and a real implementation targeting monitoring of welder machines. Our obtained results show that the proposed method outperforms the first published and most widely used IWSN standard called WirelessHART.
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