| 1. |
- Andersson, Kristoffer, 1976, et al.
(author)
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Fabrication and characterization of field-plated buried-gate SiC MESFETs
- 2006
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In: IEEE Electron Device Letters. - 0741-3106 .- 1558-0563. ; 27:7, s. 573-575
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Journal article (peer-reviewed)abstract
- Silicon carbide (SiC) MESFETs were fabricated using a standard SiC MESFET structure with the application of the "buried-channel" and field-plate (FP) techniques in the process. FPs combined with a buried-gate are shown to be favorable concerning output power density and power-added efficiency (PAE), due to higher breakdown voltage and decreased output conductance. A very high power density of 7.8 W/mm was measured on-wafer at 3 GHz for a two-finger 400-/spl mu/m gate periphery SiC MESFET. The PAE for this device was 70% at class AB bias. Two-tone measurements at 3 GHz /spl plusmn/ 100 kHz indicate an optimum FP length for high linearity operation.
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| 2. |
- Nilsson, Per-Åke, 1964, et al.
(author)
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Influence of Field Plates and Surface Traps on Microwave Silicon Carbide MESFETs
- 2008
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In: IEEE Transactions on Electron Devices. - 1557-9646 .- 0018-9383. ; 55:8, s. 1875-1879
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Journal article (peer-reviewed)abstract
- The influence of field plates and surface traps on silicon carbide MESFETs for microwave operation was investigated. By increasing the length of gate-connected field plates from 50 to 800 nm, it was possible to increase the gate–drain breakdown voltage of the devices from 125 to 170 V. At the same time, the current slump effect of traps in the passivation oxide was reduced. By using a combination of field plates and a passivation oxide with low interface trap density, it was possible to reach an output power density of 8 W/mm at 3 GHz.
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| 3. |
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| 4. |
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| 5. |
- Sudow, Mattias, 1980, et al.
(author)
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An AlGaN/GaN HEMT-Based Microstrip MMIC Process for Advanced Transceiver Design
- 2008
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In: IEEE Transactions on Microwave Theory and Techniques. - 0018-9480 .- 1557-9670. ; 56:8, s. 1827-1833
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Journal article (peer-reviewed)abstract
- A MMIC process in AlGaN/GaN technology for advanced transceiver design has been developed. The process is based on microstrip technology with a complete model library of passive elements and AlGaN/GaN HEMTs. The transistor technology in this process is suitable for both power and low noise design, demonstrated with a power density of 5 W/mm, and an ${rm NF}_{min}$ of 1.4 dB at $X$ -band. Process stability of subcircuits, complementary to power amplifiers and LNAs, in a transceiver system have been investigated. The results indicate that an all AlGaN/GaN MMIC transceiver is realizable using this technology.
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| 6. |
- Sudow, Mattias, 1980, et al.
(author)
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An SiC MESFET-based MMIC process
- 2006
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In: IEEE Transactions on Microwave Theory and Techniques. ; 54:12, Part 1, s. 4072-4078
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Journal article (peer-reviewed)abstract
- A monolithic microwave integrated circuit (MMIC)process based on an in-house SiC MESFET technology has been developed. The process uses microstrip technology, and a complete set of passive components, including MIMcapacitors, spiral inductors,thin-film resistors, and via-holes, has been developed. The potential of the process is demonstrated by an 8-W power amplifierat 3 GHz, a high-linearity -band mixer showing a third-order intercept point of 38 dBm, and a high-power limiter.
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| 7. |
- Sudow, Mattias, 1980, et al.
(author)
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The Chalmers microstrip SiC MMIC Process
- 2005
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In: Conference Proceedings Gighahertz 2005.
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Conference paper (peer-reviewed)abstract
- A generic microstrip MMIC process targeted for SiC and GaN technology has beendeveloped. Passive components for high power operation were developed and verified. Circuit modelsfor both passive and active components have been formulated. Using the developed MMIC process anamplifier and a limiter have been manufactured.
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| 8. |
- Andersson, Christer, 1982, et al.
(author)
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Epitaxial and Layout Optimization of SiC Microwave Power Varactors
- 2011
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In: Asia-Pacific Microwave Conference Proceedings, APMC (APMC 2011 ;Melbourne, VIC; 5 - 8 December 2011). - 9780858259744 ; , s. 1642-1645
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Conference paper (peer-reviewed)abstract
- SiC Schottky diode varactors have been designed for use in tunable microwave power circuits. Epitaxial growth results show excellent material uniformity with low access layer sheet resistances. Two types of device layouts have been evaluated. Island type layouts reduce the parasitic series resistance by 50-60% compared to typical finger layouts. The Q-factors of downscaled island devices are approaching the intrinsic material performance, but are limited by an increasing parasitic parallel capacitance.
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| 9. |
- Axelsson, Olle, 1986, et al.
(author)
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Impact of Trapping Effects on the Recovery Time of GaN Based Low Noise
- 2016
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In: IEEE Microwave and Wireless Components Letters. - : Institute of Electrical and Electronics Engineers (IEEE). - 1558-1764 .- 1531-1309. ; 26:1, s. 31-33
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Journal article (peer-reviewed)abstract
- This study investigates recovery time of the gain of AlGaN/GaN HEMT based low noise amplifiers (LNA) after an input overdrive pulse. Three LNAs, fabricated in two commercial MMIC processes and a Chalmers in-house process, are evaluated. The Chalmers process has an unintentionally doped buffer instead of the intentional Fe doping of the buffer which is standard in commercial GaN HEMT technologies. It is shown that the LNAs from the two commercial processes experience a severe drop in gain after input overdrive pulses higher than 28 dBm, recovering over a duration of around 20 ms. In contrast the LNA fabricated in-house at Chalmers experienced no visible effects up to an input power of 33 dBm. These results have impact for radar and electronic warfare receivers, which need to be operational immediately after an overdrive pulse. The long time constants suggest that these effects are due to trapping in the transistors with the Fe doped buffer playing an important role.
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| 10. |
- Billström, Niklas, et al.
(author)
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High performance GaN front-end MMICs
- 2011
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In: 14th European Microwave Week 2011: "Wave to the Future", EuMW 2011 - 6th European Microwave Integrated Circuit Conference, EuMIC 2011, Manchester, 10 October through 11 October 2011. - 9782874870231 ; , s. 348-351
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Conference paper (peer-reviewed)
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