AlGaN Microwave Power HFETs on Insulating SiC Substrates

1999 ◽  
Vol 572 ◽  
Author(s):  
Gerry Sullivan ◽  
Ed Gertner ◽  
Richard Pittman ◽  
Mary Chen ◽  
Richard Pierson ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Total Power ◽  
Thermal Impedance ◽  
Rf Power ◽  
Power Performance ◽  
Large Area ◽  
High Power Microwave ◽  
Sapphire Substrates ◽  
Pulsed Measurements ◽  
Power Microwave

ABSTRACTAIGaN HFETs are attractive devices for high power microwave applications. Sapphire, which is the typical substrate for AlGaN epitaxy, has a very poor thermal conductivity, and the power performance of AlGaN HFETs fabricated on sapphire substrates is severely limited due to this large thermal impedance. We report on HFETs fabricated on high thermal conductivity electrically insulating SiC substrates. Excellent RF power performance for large area devices is demonstrated. On-wafer CW measurements at 10 GHz of a 320 micron wide FET resulted in an RF power density of 2.8 Watts/mm, and measurements of a 1280 micron wide FET resulted in a total power of 2.3 Watts. On-wafer pulsed measurements, at 8 GHz, of a 1280 micron wide FET resulted in a total power of 3.9 Watts. Design of a hybrid microwave amplifier will be discussed.

Seeded Growth of AlN on (0001)-Plane 6H-SiC Substrates

2009 ◽  
Vol 615-617 ◽  
pp. 983-986 ◽  
Author(s):  
Octavian Filip ◽  
Boris M. Epelbaum ◽  
Matthias Bickermann ◽  
Paul Heimann ◽  
S. Nagata ◽  
...  
Keyword(s):  
Growth Rates ◽  
Thermal Field ◽  
Substrate Material ◽  
Vapor Transport ◽  
Structural Quality ◽  
Seeded Growth ◽  
Large Area ◽  
Slow Cooling ◽  
High Power Microwave ◽  
Power Microwave

Aluminum nitride (AlN) is a promising substrate material for epitaxy of Al-rich III-nitrides to be employed, e.g., in deep-UV optoelectronic and high-power microwave devices. In this context, preparation of bulk AlN crystals by physical vapor transport (PVT) appears to be of most importance. In this work, seeded growth of AlN on (0001)-plane 6H-SiC substrates was investigated. SiC substrates with a diameter of 15 mm were used. AlN layers with thicknesses up to 3 mm were deposited at growth rates in the range of 10 to 40 μm/hour. Such templates provide large-area seeds, but they are often cracked, especially at thicknesses below 1mm. Besides cracks, other defects from the SiC seed propagate into the AlN layer and subsequently into the bulk AlN crystal. That is why, the aim of this work is to assess structural quality and defect content in thick AlN templates grown on (0001) plane SiC substrates. An optimum thickness-quality, the most appropriate growth stage for further use of the AlN template as a seed for subsequent PVT growth of bulk AlN growth, will be provided. We found that low growth rates mitigate crack propagation; slow cooling as well as optimization of the thermal field inside the crucible can prevent formation of new cracks after growth.

Metamaterials for Rapidly Forming Large-Area Distributed Plasma Discharges for High-Power Microwave Applications

2015 ◽  
Vol 43 (12) ◽  
pp. 4099-4109 ◽  
Author(s):  
Chien-Hao Liu ◽  
Paul Carrigan ◽  
Brian J. Kupczyk ◽  
Xun Xiang ◽  
Nader Behdad ◽  
...  
Keyword(s):  
High Power ◽  
Plasma Discharges ◽  
Large Area ◽  
High Power Microwave ◽  
Microwave Applications ◽  
Power Microwave

scholarly journals Experimental study on a high power microwave amplifier driven by low rf power

2011 ◽  
Vol 60 (4) ◽  
pp. 044102
Author(s):  
Wu Yang ◽  
Xu Zhou ◽  
Xu Yong ◽  
Jin Xiao ◽  
Chang An-Bi ◽  
...  
Keyword(s):  
Experimental Study ◽  
High Power ◽  
Rf Power ◽  
High Power Microwave ◽  
Microwave Amplifier ◽  
Power Microwave

scholarly journals Design of a dual-frequency high-power microwave generator

2011 ◽  
Vol 29 (4) ◽  
pp. 479-485 ◽  
Author(s):  
Juntao He ◽  
Yibing Cao ◽  
Jiande Zhang ◽  
Ting Wang ◽  
Junpu Ling
Keyword(s):  
High Power ◽  
Microwave Power ◽  
Wave Interaction ◽  
Total Power ◽  
Dual Frequency ◽  
High Power Microwave ◽  
Beam Wave ◽  
Interaction Efficiency ◽  
Beam Wave Interaction ◽  
Power Microwave

AbstractA new direction for high-power microwave (HPM) development is to investigate devices capable of producing HPMs with a complicated spectrum. In recent years, some HPM sources with two stable and separate frequencies have been investigated theoretically and experimentally. However, many short-comings still exist in these devices. Especially, the beam-wave interaction efficiency and the output microwave power are low in such devices. This paper proposes a novel dual-frequency HPM generator based on transition radiation. In the device, the electromagnetic fields are localized near the resonator cavities in the form of standing waves, and thus the interference between the different HPM components with different frequencies is weak. Compared with the existing dual-frequency devices, the new structure allows high beam-wave interaction efficiency and high output microwave power. As indicated in particle-in-cell simulation, with an electron beam of 500 kV voltage and 15.0 kA current guided by a magnetic field of 0.8 Tesla, an average power of 1.60 GW with a total power conversion efficiency of 21.3% is obtained, and the frequencies are 1.53 GHz and 3.29 GHz, respectively. Power level between two HPMs is comparable. The simulation results verify the feasibility of the dual-frequency HPM generator.

The resistive sensor: a device for high-power microwave pulsed measurements

2001 ◽  
Vol 43 (5) ◽  
pp. 64-79 ◽  
Author(s):  
M. Dagys ◽  
I. Kancleris ◽  
R. Simniskis ◽  
E. Schamiloglu ◽  
F.J. Agee
Keyword(s):  
High Power ◽  
High Power Microwave ◽  
Resistive Sensor ◽  
Pulsed Measurements ◽  
Power Microwave
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