Journal ArticleDOI
AlGaN/AlN/GaN high-power microwave HEMT
L. Shen,Sten Heikman,Brendan Jude Moran,Robert Coffie,N.-Q. Zhang,D. Buttari,I. P. Smorchkova,Stacia Keller,Steven P. DenBaars,Umesh K. Mishra +9 more
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TLDR
In this paper, a novel heterojunction AlGaN/AlN/GaN high-electron mobility transistor (HEMT) is discussed, where the insertion of the very thin AlN interfacial layer (/spl sim/1 nm) maintains high mobility at high sheet charge densities by increasing the effective /spl Delta/E/sub C/ and decreasing alloy scattering.Abstract:
In this letter, a novel heterojunction AlGaN/AlN/GaN high-electron mobility transistor (HEMT) is discussed. Contrary to normal HEMTs, the insertion of the very thin AlN interfacial layer (/spl sim/1 nm) maintains high mobility at high sheet charge densities by increasing the effective /spl Delta/E/sub C/ and decreasing alloy scattering. Devices based on this structure exhibited good DC and RF performance. A high peak current 1 A/mm at V/sub GS/=2 V was obtained and an output power density of 8.4 W/mm with a power added efficiency of 28% at 8 GHz was achieved.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
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
AlGaN/GaN high electron mobility transistors with InGaN back-barriers
Tomas Palacios,Arpan Chakraborty,Sten Heikman,Stacia Keller,Steven P. DenBaars,Umesh K. Mishra +5 more
TL;DR: In this paper, a GaN/ultrathin InGaN/GaN heterojunction was used to provide a backbarrier to the electrons in an AlGaN and GaN high-electron mobility transistor (HEMT).
Journal ArticleDOI
Nanowire Transistor Performance Limits and Applications
TL;DR: In this paper, the authors review advances in chemically synthesized semiconductor nanowires as nanoelectronic devices and discuss 3-D heterogeneous integration that is uniquely enabled by multifunctional nanowire within a bottom-up approach.
Journal ArticleDOI
Dopant-Free GaN/AlN/AlGaN Radial Nanowire Heterostructures as High Electron Mobility Transistors
Yat Li,Jie Xiang,Fang Qian,Silvija Gradečak,Yue Wu,Hao Yan,Douglas A. Blom,Charles M. Lieber +7 more
TL;DR: The ability to control synthetically the electronic properties of nanowires using band structure design in III-nitride radial nanowire heterostructures opens up new opportunities for nanoelectronics and provides a new platform to study the physics of low-dimensional electron gases.
References
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Journal ArticleDOI
Two-dimensional electron gases induced by spontaneous and piezoelectric polarization charges in N- and Ga-face AlGaN/GaN heterostructures
Oliver Ambacher,Joseph A. Smart,James R. Shealy,Nils Weimann,K. Chu,M. J. Murphy,William J. Schaff,L.F. Eastman,Roman Dimitrov,L. Wittmer,Martin Stutzmann,W. Rieger,J. Hilsenbeck +12 more
TL;DR: In this article, the authors investigated the role of spontaneous and piezoelectric polarization on the carrier confinement at GaN/AlGaN and AlGaN/GaN interfaces.
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
The effect of surface passivation on the microwave characteristics of undoped AlGaN/GaN HEMTs
TL;DR: In this paper, the authors reported the highest reported microwave power density for undoped sapphire substrated AlGaN/GaN HEMT's on the same wafer.
Journal ArticleDOI
Very-high power density AlGaN/GaN HEMTs
TL;DR: A flip-chip amplifier IC using a 4-mm device generated 14 W at 8 GHz, representing the highest CW power obtained from GaN-based integrated circuits to date.
Journal ArticleDOI
AlN/GaN and (Al,Ga)N/AlN/GaN two-dimensional electron gas structures grown by plasma-assisted molecular-beam epitaxy
I. P. Smorchkova,L. F. Chen,Tom Mates,L. Shen,Sten Heikman,Brendan Jude Moran,Stacia Keller,Steven P. DenBaars,James S. Speck,Umesh Mishra +9 more
TL;DR: In this article, an extensive study of the two-dimensional electron gas (2DEG) structures containing AlN layers was conducted and it was shown that the presence of large polarization fields in the AlN barrier layer in AlN/GaN heterostructures results in high values of the 2DEG sheet density of up to 3.6×1013 cm−2.