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ABSTRACT: Wide bandgap (WBG) devices offer significant advantages for next generation military and commercial systems. SiC MESFETs currently achieve power densities of 4.0 W/mm with power added efficiencies in excess of 60% on a repeatable basis. They are commercially available in packaged or die formats and have been successfully designed into a number of systems. GaN is also extremely promising as a next generation wide bandgap device. Cree has demonstrated power densities higher than 25 watts per mm of gate periphery. With f<sub>tau</sub>'s > 40 GHz, GaN devices have the capability of satisfying system device requirements from UHF through millimeter-wave. Both technologies are now also offered through commercial MMIC foundry services using design rules and non-linear models provided for external designers. Significant progress has also been made in the development of 100-mm SiC substrates and WBG epitaxy (SiC and GaN) which is key for commercializing the technology and providing low costs. Micropipe densities as low as 2.5 cm<sup>-2</sup> have been demonstrated for 100-mm HPSI substrates and both SiC and GaN epitaxy with excellent intra-wafer sheet resistance uniformity have been demonstrated. With robust reliability for SiC MESFETs now established for several years, the latest results for GaN device reliability benchmarking are shown.
Radar Conference, 2007 IEEE; 05/2007
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ABSTRACT: A high-power amplifier using two 28.8-mm-periphery GaN HEMTs was demonstrated with all matching components inside the package. When biased at 55 V, a power bandwidth of 3.3-3.6 GHz was obtained, with 550-Wpeak output, 12.5-dB associated gain and 66% drain efficiency at 3.45 GHz
Electron Devices Meeting, 2006. IEDM '06. International; 01/2007
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P. Parikh,
Y.-F. Wu,
M. Moore,
P. Chavarkar,
T. Wisleder,
U.K. Mishra, S. Sheppard,
R.P. Smith,
A. Saxler,
S. Alien,
J. Milligan,
J. Palmour
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ABSTRACT: With the rapid progress and maturation over the last several years, wide bandgap GaN-based HEMTs are now regarded as the next generation technology leader for high frequency and high power device applications as stated in U. K. Mishra et al. (2002). The Al<sub>x</sub>Ga<sub>1 - x</sub>N-GaN heterostructure system enables high voltage, high current operation, resulting in the demonstration of > 10× power performance than GaAs and Si technologies. The high RF power density (W/mm) translates into high watts per unit capacitance (W/pF), resulting in high impedance and simpler matching, an enabler for wide-bandwidth applications. This paper reviews the recent progress in material, device and circuit performance of GaN HEMTs by the Cree team.
Future of Electron Devices, 2004. International Meeting for; 08/2004
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ABSTRACT: Recently, electric field modification with GaN-based high-electron-mobility-transistors (HEMTs) using field plates (FP) has resulted in dramatically enhanced power performance. Power densities up to 32 W/mm at 4 GHz have been demonstrated with power-added-efficiency (PAE) of 55%. When scaled to a large periphery, a total output power of 149 W was obtained at 2 GHz. Modern communication applications also require high linearity for power devices. Here we present the linearity performance of GaN-channel HEMTs with various FP lengths at biases up to 108V.
Device Research Conference, 2004. 62nd DRC. Conference Digest [Includes 'Late News Papers' volume]; 07/2004
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ABSTRACT: GaN high-electron-mobility-transistors (HEMTs) on SiC were fabricated with field plates of various dimensions for optimum performance. Great enhancement in radio frequency (RF) current-voltage swings was achieved with acceptable compromise in gain, through both reduction in the trapping effect and increase in breakdown voltages. When biased at 120 V, a continuous wave output power density of 32.2 W/mm and power-added efficiency (PAE) of 54.8% at 4 GHz were obtained using devices with dimensions of 0.55×246 μm<sup>2</sup> and a field-plate length of 1.1 μm. Devices with a shorter field plate of 0.9 μm also generated 30.6 W/mm with 49.6% PAE at 8 GHz. Such ultrahigh power densities are a dramatic improvement over the 10-12 W/mm values attained by conventional gate GaN-based HEMTs.
IEEE Electron Device Letters 04/2004; · 2.85 Impact Factor
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P. Parikh,
Y.-F. Wu,
P. Chavarkar,
M. Moore,
U.K. Mishra, S. Sheppard,
R P Smith,
A. Saxler,
J. Duc,
W. Pribble,
J. Milligan,
J. Palmour
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ABSTRACT: In this paper recent progress in material, device and circuit technology of GaN based HEMT is discussed. We have also developed GaN HEMT hybrid amplifiers as well as MMICs, including air wedge and MIMC capacitors and resistors.
Compound Semiconductors, 2003. International Symposium on; 09/2003
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P. Parikh,
Y.-F. Wu,
P. Chavarkar,
M. Moore,
U.K. Mishra, S. Sheppard,
R.P. Smith,
A. Saxler,
W. Pribble,
S. Allen,
J. Milligan,
J. Palmour
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ABSTRACT: The enabling features and performance of GaN based HEMTs as a high power, high bandwidth semiconductor technology are presented. Progress on materials development includes the development of AlGaN and AlN barrier HEMTs with room temperature electron mobility exceeding 2000 cm<sup>2</sup>/V-s. Trap free GaN HEMT devices with > 10 W/mm power density and devices with > 70 % efficiency are presented. Operation at > 200 °C is reported. Simultaneous linearity and efficiency under class B is presented followed by discussion of mm-wave power performance. Finally, device scaling resulting in a total power > 100 Watts and GaN HEMT circuit demonstrations are presented including mm-wave amplifier with > 3 Watts at 30 GHz and 35 GHz.
Compound Semiconductors: Post-Conference Proceedings, 2003 International Symposium on; 09/2003
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ABSTRACT: Wide bandgap (WBG) devices offer significant advantages for next generation military and commercial systems. SiC MESFETs currently achieve power densities of 4.0 W/mm with power added efficiencies in excess of 60% on a repeatable basis. GaN is also extremely promising as a next generation wide bandgap device. Cree currently offers a number of commercial products targeted at both broadband wireless and general-purpose markets. Results for two such products will be reviewed. SiC MESFETs and GaN HEMT MMICs are also offered through commercial MMIC foundry services using standard design rules and internally developed non-linear models. Using this MMIC process, results will be shown for two new commercial GaN MMIC products that have been developed for general-purpose applications in the 2.5-6.0 GHz and DC-6.0 GHz bands respectively. Additionally, preliminary results are shown for a 2-stage high efficiency S-band switch mode amplifier operating from 3.1-3.5 GHz. Significant progress has also been made in the development of 100-mm SiC substrates which is key for commercializing the technology and providing low costs. Micropipe densities as low as 2.5 cm -2 have been demonstrated for 100-mm HPSI substrates. With robust reliability for SiC MESFETs now established for several years, the latest results for GaN device reliability benchmarking are also shown.
