GaN-on-Diamond HEMTs with 11W/mm Output Power at 10GHz

MRS Advances ◽  
2016 ◽  
Vol 1 (2) ◽  
pp. 147-155 ◽  
Author(s):  
P.C. Chao ◽  
Kanin Chu ◽  
Jose Diaz ◽  
Carlton Creamer ◽  
Scott Sweetland ◽  
...  
Keyword(s):  
Low Temperature ◽  
Continuous Wave ◽  
Electrical Performance ◽  
Limiting Factor ◽  
Rf Power ◽  
Power Performance ◽  
Electronic Warfare ◽  
Power Added Efficiency ◽  
New Device ◽  
Diamond Substrate

ABSTRACTA new device-first low-temperature bonded gallium nitride (GaN)-on-diamond high-electronic mobility transistor (HEMT) technology with state-of-the-art, radio frequency (RF) power performance is described. In this process, the devices were first fabricated on a GaN-on-silicon carbide (SiC) epitaxial wafer and were subsequently separated from the SiC and bonded onto a high-thermal-conductivity diamond substrate. Thermal measurements showed that the GaN-on-diamond devices maintained equivalent or lower junction temperatures than their GaN-on-SiC counterparts while delivering more than three-times higher RF power within the same active area. Such results demonstrate that the GaN device transfer process is capable of preserving intrinsic transistor electrical performance while taking advantage of the excellent thermal properties of diamond substrates. Preliminary step-stress and room-temperature, steady-state life testing shows that the low-temperature bonded GaN-on-diamond device has no inherently reliability limiting factor. GaN-on-diamond is ideally suited to wideband electronic warfare (EW) power amplifiers as they are the most thermally challenging due to continuous wave (CW) operation and the reduced power-added efficiency obtained with ultra-wide bandwidth circuit implementations.

scholarly journals Broadband Performance Assessment of an RF Power Transistor Employing the Real Frequency Technique

2022 ◽  
Author(s):  
siddik yarman
Keyword(s):  
Numerical Procedure ◽  
Rf Power ◽  
Power Performance ◽  
Power Transistor ◽  
Gain Bandwidth ◽  
Active Device ◽  
Power Added Efficiency ◽  
Real Frequency ◽  
The Given ◽  
Load Pull

selected active device is essential to design an RF power amplifier for optimum gain and power added efficiency. As they are obtained, these impedances may not be realizable network functions over the desired frequency band to yield the input and the output matching networks for the amplifier. Therefore, in this paper, first, we introduce a new method to test if a given impedance is realizable. Then, a novel “Real Frequency Line Segment Technique” based numerical procedure is introduced to assess the gain-bandwidth limitations of the given source and load impedances, which in turn results in the ultimate RF-power intake/ delivering performance of the amplifier. During the numerical performance assessments process, a robust tool called “Virtual Gain Optimization” is presented. Finally, a new definition called “Power-Performance-Product” is introduced to measure the quality of an active device. Examples are presented to test the realizability of the given source/load pull data and to assess the gain-bandwidth limitations of the given source/load pull impedances for a 45W-GaN power transistor, namely “Cree CG2H40045”, over 0.8 -3.8 GHz bandwidth.

RF Power Performance Evaluation of Surface Channel Diamond MESFET

2009 ◽  
Vol 1203 ◽  
Author(s):  
Maria Cristina Rossi ◽  
Paolo Calvani ◽  
Gennaro Conte ◽  
Vittorio Camarchia ◽  
Federica Cappelluti ◽  
...  
Keyword(s):  
Output Power ◽  
Threshold Voltage ◽  
Polycrystalline Diamond ◽  
Drain Current ◽  
Rf Power ◽  
Power Performance ◽  
Power Devices ◽  
Large Signal ◽  
Device Structure ◽  
Power Added Efficiency

AbstractLarge-signal radiofrequency performances of surface channel diamond MESFET fabricated on hydrogenated polycrystalline diamond are investigated. The adopted device structure is a typical coplanar two-finger gate layout, characterized in DC by an accumulation-like behavior with threshold voltage Vt ∼ 0-0.5 V and maximum DC drain current of 120 mA/mm. The best radiofrequency performances (in terms of fT and fmax) were obtained close to the threshold voltage. Realized devices are analyzed in standard class A operation, at an operating frequency of 2 GHz. The MESFET devices show a linear power gain of 8 dB and approximately 0.2 Wmm RF output power with 22% power added efficiency. An output power density of about 0.8 W/mm can be then extrapolated at 1 GHz, showing the potential of surface channel MESFET technology on polycrystalline diamond for microwave power devices.

scholarly journals Broadband Performance Assessment of an RF Power Transistor Employing the Real Frequency Technique

2022 ◽  
Author(s):  
siddik yarman
Keyword(s):  
Numerical Procedure ◽  
Rf Power ◽  
Power Performance ◽  
Power Transistor ◽  
Gain Bandwidth ◽  
Active Device ◽  
Power Added Efficiency ◽  
Real Frequency ◽  
The Given ◽  
Load Pull

selected active device is essential to design an RF power amplifier for optimum gain and power added efficiency. As they are obtained, these impedances may not be realizable network functions over the desired frequency band to yield the input and the output matching networks for the amplifier. Therefore, in this paper, first, we introduce a new method to test if a given impedance is realizable. Then, a novel “Real Frequency Line Segment Technique” based numerical procedure is introduced to assess the gain-bandwidth limitations of the given source and load impedances, which in turn results in the ultimate RF-power intake/ delivering performance of the amplifier. During the numerical performance assessments process, a robust tool called “Virtual Gain Optimization” is presented. Finally, a new definition called “Power-Performance-Product” is introduced to measure the quality of an active device. Examples are presented to test the realizability of the given source/load pull data and to assess the gain-bandwidth limitations of the given source/load pull impedances for a 45W-GaN power transistor, namely “Cree CG2H40045”, over 0.8 -3.8 GHz bandwidth.

scholarly journals Nanonet: Low-temperature-processed tellurium nanowire network for scalable p-type field-effect transistors and a highly sensitive phototransistor array

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Muhammad Naqi ◽  
Kyung Hwan Choi ◽  
Hocheon Yoo ◽  
Sudong Chae ◽  
Bum Jun Kim ◽  
...  
Keyword(s):  
Low Temperature ◽  
Field Effect ◽  
High Performance ◽  
Field Effect Transistors ◽  
Optical Measurements ◽  
Electrical Performance ◽  
Large Area ◽  
Nanowire Network ◽  
P Type ◽  
Nanowire Networks

AbstractLow-temperature-processed semiconductors are an emerging need for next-generation scalable electronics, and these semiconductors need to feature large-area fabrication, solution processability, high electrical performance, and wide spectral optical absorption properties. Although various strategies of low-temperature-processed n-type semiconductors have been achieved, the development of high-performance p-type semiconductors at low temperature is still limited. Here, we report a unique low-temperature-processed method to synthesize tellurium nanowire networks (Te-nanonets) over a scalable area for the fabrication of high-performance large-area p-type field-effect transistors (FETs) with uniform and stable electrical and optical properties. Maximum mobility of 4.7 cm2/Vs, an on/off current ratio of 1 × 104, and a maximum transconductance of 2.18 µS are achieved. To further demonstrate the applicability of the proposed semiconductor, the electrical performance of a Te-nanonet-based transistor array of 42 devices is also measured, revealing stable and uniform results. Finally, to broaden the applicability of p-type Te-nanonet-based FETs, optical measurements are demonstrated over a wide spectral range, revealing an exceptionally uniform optical performance.

scholarly journals Comparative investigation of lasing and amplification performance in cryogenic Yb:YLF systems

2021 ◽  
Vol 127 (3) ◽  
Author(s):  
Umit Demirbas ◽  
Martin Kellert ◽  
Jelto Thesinga ◽  
Yi Hua ◽  
Simon Reuter ◽  
...  
Keyword(s):  
Continuous Wave ◽  
Estimation Method ◽  
Laser Cavity ◽  
Comparative Investigation ◽  
Limiting Factor ◽  
Experimental Conditions ◽  
Temperature Estimation ◽  
Transverse Temperature ◽  
First Time

AbstractWe present detailed experimental results with cryogenic Yb:YLF gain media in rod-geometry. We have comparatively investigated continuous-wave (cw) lasing and regenerative amplification performance under different experimental conditions. In the cw lasing experiments effect of crystal doping, cw laser cavity geometry and pump wavelength on lasing performance were explored. Regenerative amplification behavior was analyzed and the role of depolarization losses on performance was investigated. A recently developed temperature estimation method was also employed for the first time in estimating average crystal temperature under lasing conditions. It is shown that the thermal lens induced by transverse temperature gradients is the main limiting factor and strategies for future improvements are discussed. To the best of our knowledge, the achieved results in this study (375 W in cw, and 90 W in regenerative amplification) are the highest average powers ever obtained from this system via employing the broadband E//a axis.

Low Temperature Silicon Oxidation With Electron Cyclotron Resonance Oxygen Plasma

1991 ◽  
Vol 235 ◽  
Author(s):  
K. T. Sung ◽  
S. W. Pang
Keyword(s):  
Low Temperature ◽  
Microwave Power ◽  
Cyclotron Resonance ◽  
Oxygen Plasma ◽  
Permanent Magnets ◽  
Electron Cyclotron Resonance ◽  
Electron Cyclotron ◽  
Rf Power ◽  
Source Distance ◽  
Ecr Source

ABSTRACTSilicon was oxidized at low temperature with an oxygen plasma generated by an electron cyclotron resonance (ECR) source. The ECR source utilized a multicusp magnetic field formed by permanent magnets. Microwave power at 2.45 GHz was applied to the source and if power at 13.56 MHz was applied to the sample stage. Si oxidation was studied as a function of source distance, pressure, microwave power, and rf power. The oxide thickness increases with microwave and rf power but decreases with source distance. The oxidation rate increases with pressure up to 12 mTorr, men decreases at higher pressure. The relative emission intensities in the plasma monitored using optical emission spectroscopy showed similar dependence on the source distance and microwave power. Oxidation temperature was estimated to be <100°C. Using ellipsometry and X-ray photoelectron spectroscopy, the oxidized films were found to be close to that of thermal oxide with refractive index at 1.45 and oxygen to silicon ratio of 2. From the current-voltage and capacitance-voltage measurements, the breakdown fields of these oxide films were 6.3 MV/cm and the fixed charge densities were 7×1010 cm−2.

RF power performance evaluation of surface channel diamond MESFETs

2011 ◽  
Vol 55 (1) ◽  
pp. 19-24 ◽  
Author(s):  
V. Camarchia ◽  
F. Cappelluti ◽  
G. Ghione ◽  
M.C. Rossi ◽  
P. Calvani ◽  
...  
Keyword(s):  
Performance Evaluation ◽  
Rf Power ◽  
Power Performance

AlGaN/GaN HEMTs: RECENT DEVELOPMENTS AND FUTURE DIRECTIONS

2008 ◽  
Vol 18 (04) ◽  
pp. 913-922 ◽  
Author(s):  
SIDDHARTH RAJAN ◽  
UMESH K. MISHRA ◽  
TOMÁS PALACIOS
Keyword(s):  
Field Effect ◽  
High Speed ◽  
Digital Circuits ◽  
Field Effect Transistors ◽  
Rf Power ◽  
Power Performance ◽  
Future Directions ◽  
Recent Developments ◽  
Gan Hemts ◽  
State Of Art

This paper provides an overview of recent work and future directions in Gallium Nitride transistor research. We discuss the present status of Ga -polar AlGaN / GaN HEMTs and the innovations that have led to record RF power performance. We describe the development of N -polar AlGaN / GaN HEMTs with microwave power performance comparable with state-of-art Ga -polar AlGaN / GaN HEMTs. Finally we will discuss how GaN -based field effect transistors could be promising for a less obvious application: low-power high-speed digital circuits.

scholarly journals Plasmonics in semiconductors and in Ag submicron wires and graphene

2016 ◽  
Vol 55 (4) ◽  
Author(s):  
Hans Hartnagel ◽  
Shihab Al-Daffaie ◽  
Oktay Yilmazoglu
Keyword(s):  
Continuous Wave ◽  
Silver Nanowires ◽  
Field Enhancement ◽  
New Device ◽  
Domain Structures ◽  
New Concepts ◽  
Metal Nanostructure ◽  
Thz Sources ◽  
Nitrogen Ion ◽  
Optical Focusing

Some 50 years ago discussions of plasmonics in semiconductors lead to many new concepts such as travelling domain structures with applications leading even to logic systems. Now plasmonics of submicron wires of Ag and graphene bring new device concepts for the fabrication of compact THz sources and optical focusing of the beat signal into the active area. Here as an experimental example such new opportunities are involved with compact THz sources based on optical laser mixing. They include resonant plasmonic structures at THz and optical frequencies to locally enhance the electromagnetic fields at THz as well as optical frequencies by the combination of semiconductor-graphene plasmons respectively by the semiconductor-metal-nanostructure plasmons. Of particular interest is the usage of graphene, which is optically transmitting and which is either a semimetal or can be transformed into a semiconductor by reducing the width of its strips to about 30 nm, opening a band gap in the meV to tens of the meV range. A successful experimental structure for continuous-wave THz photomixing is fabricated using 1D and 2D nanocontacts either on low-temperature-grown (LTG) GaAs or on nitrogen ion-implanted (N+i) GaAs and graphene sheets. The overlaying 1D and 2D nanocontacts were formed by silver nanowires with a diameter of 60 or 120 nm. They can handle currents of >10 and >30 mA, respectively, without electromigration enabling reliably high photocurrents and field enhancement at THz frequencies by plasmonic effects. The nanomaterial structurization in connection with present-day plasmonic applications is now to be discussed in a similar manner as past opportunities with semiconductor plasmonics.

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