Journal ArticleDOI
The effect of surface passivation on the microwave characteristics of undoped AlGaN/GaN HEMTs
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TLDR
In this paper, the authors reported the highest reported microwave power density for undoped sapphire substrated AlGaN/GaN HEMT's on the same wafer.Abstract:
Surface passivation of undoped AlGaN/CaN HEMT's reduces or eliminates the surface effects responsible for limiting both the RF current and breakdown voltages of the devices. Power measurements on a 2/spl times/125/spl times/0.5 /spl mu/m AlGaN/GaN sapphire based HEMT demonstrate an increase in 4 GHz saturated output power from 1.0 W/mm [36% peak power-added efficiency (PAE)] to 2.0 W/mm (46% peak PAE) with 15 V applied to the drain in each case. Breakdown measurement data show a 25% average increase in breakdown voltage for 0.5 /spl mu/m gate length HEMT's on the same wafer. Finally, 4 GHz power sweep data for a 2/spl times/75/spl times/0.4 /spl mu/m AlGaN/GaN HEMT on sapphire processed using the Si/sub 3/N/sub 4/ passivation layer produced 4.0 W/mm saturated output power at 41% PAE (25 V drain bias). This result represents the highest reported microwave power density for undoped sapphire substrated AlGaN/GaN HEMT's.read more
Citations
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Journal ArticleDOI
GaN-Based RF Power Devices and Amplifiers
TL;DR: The latest developments of the GaN HEMT technologies, including material growth, processing technologies, device epitaxial structures and MMIC designs, are reviewed to achieve the state-of-the-art microwave and millimeter-wave performance.
Journal ArticleDOI
The impact of surface states on the DC and RF characteristics of AlGaN/GaN HFETs
TL;DR: In this article, the authors show that the cause of current collapse is a charging up of a second virtual gate, physically located in the gate drain access region, thus acting as a negatively charged virtual gate.
Journal ArticleDOI
A Review of GaN on SiC High Electron-Mobility Power Transistors and MMICs
TL;DR: Examples of broadband amplifiers, as well as several of the main areas of high-efficiency amplifier design-notably Class-D, Class-E, class-F, and Class-J approaches, Doherty PAs, envelope-tracking techniques, and Chireix outphasing are described.
Journal ArticleDOI
Trapping effects in GaN and SiC microwave FETs
TL;DR: This paper reviews the various trapping phenomena observed in SiC- and GaN-based FETs that contribute to compromised power performance and the measurement techniques utilized to identify these traps.
Journal ArticleDOI
Fabrication and performance of GaN electronic devices
TL;DR: In this paper, the development of fabrication processes for these devices and the current state-of-the-art in device performance, for all of these structures, are discussed. And the authors also detail areas where more work is needed, such as reducing defect densities and purity of epitaxial layers, the need for substrates and improved oxides and insulators, improved p-type doping and contacts and an understanding of the basic growth mechanisms.
References
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Journal ArticleDOI
Fabrication and Characterization of GaN FETs
TL;DR: The current status of GaN-based FET technology and performance is reviewed in this paper, where fabrication details and the dc and microwave characteristics of the GaN MESFETs that utilize Si-doped channels on semi-insulating buffer layers are presented.
Journal ArticleDOI
Large signal frequency dispersion of AlGaN/GaN heterostructure field effect transistors
TL;DR: In this article, a lossy dielectric layer was incorporated in a microwave AlGaN/GaN MODFET power device to enable an interpretation of the RF power compression observed in these devices.
Journal ArticleDOI
AlGaN/GaN heterostructures on insulating AlGaN nucleation layers
TL;DR: In this paper, a single temperature process using AlGaN nucleation layers has been developed that produces device-quality, GaN-based materials with bilayer step surfaces, where the GaN layer is deposited by flow modulation organometallic vapor phase epitaxy at temperatures in excess of 1000°C.
Proceedings ArticleDOI
High Al-content AlGaN/GaN HEMTs on SiC substrates with very high power performance
TL;DR: In this article, high Al content AlGaN/GaN HEMTs on SiC substrates are demonstrated with remarkable performance enhancement, achieving power densities of 5.3-6.9 W/mm at 10 GHz from small devices, as well as a total output power of 9.1 W at 7.4 GHz from a 3mm-wide device.
Proceedings ArticleDOI
Passivation of AlGaN/GaN heterostructures with silicon nitride for insulated gate transistors
TL;DR: In this article, the effect of surface passivation on undoped AlGaN/GaN heterostructures using silicon nitride is presented, and a simple polarization model based on interface charges is presented to explain this enhancement, and compared with Hall effect and capacitance voltage (C-V) measurements of passivated and unpassivated structures.