A5028097021- GaN-based semiconductor devices and materials
- Radio Frequency Integrated Circuit Design
- Silicon Carbide Semiconductor Technologies
- Advanced Power Amplifier Design
- Semiconductor materials and devices
- Semiconductor Quantum Structures and Devices
- Microwave Engineering and Waveguides
- Ga2O3 and related materials
- Advancements in Semiconductor Devices and Circuit Design
- Acoustic Wave Resonator Technologies
- Semiconductor Lasers and Optical Devices
- Advanced DC-DC Converters
- Electromagnetic Compatibility and Noise Suppression
- ZnO doping and properties
- Advancements in PLL and VCO Technologies
- Metal and Thin Film Mechanics
- Superconducting and THz Device Technology
- Wireless Power Transfer Systems
- Semiconductor materials and interfaces
- Full-Duplex Wireless Communications
- Plasma Diagnostics and Applications
- Gyrotron and Vacuum Electronics Research
- Superconducting Materials and Applications
- Magneto-Optical Properties and Applications
- Thermal properties of materials
Fraunhofer Institute for Applied Solid State Physics
2016-2025
University of Freiburg
2021-2024
University College London
2024
University of Duisburg-Essen
2024
Deutsche Forschungsgemeinschaft
2024
Conference Board
2024
Tokyo Institute of Technology
2024
Fraunhofer Society
2005-2015
Delft University of Technology
2013-2015
University of Birmingham
2013
In this paper, an extended version of the continuous class- <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">F</i> <sup xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> mode power amplifier (PA) design approach is presented. A new formulation describing current waveform in terms just two additional parameters, while maintaining a constant half-wave rectified sinusoidal voltage waveform, allows multiple solutions fundamental and second-harmonic...
Alloys of scandium with AlN exhibit an enhanced piezoelectric coefficient that can boost the performance nitride‐based electronic and optoelectronic devices such as high electron mobility transistors (HEMTs). Consequently, there is increasing interest in epitaxial growth high‐quality AlScN/GaN heterostructures. So far, only very recent reports on AlScN HEMT structures grown by molecular beam epitaxy (MBE) have been published. Herein, motivation for depositing layers metal‐organic chemical...
This paper gives a detailed analysis on the assembly and packaging technologies for state-of-the-art GaN-based high-electron-mobility transistors, which are suitable high-temperature high-power applications. Silver sintering transient liquid phase bonding were selected as die-attachment techniques, gold palladium investigated electrical interconnection materials. Both die-attachments characterized their stability up to 450 °C. Systematic characterizations performed from on-wafer measurements...
In this article, we present a set of gallium nitride (GaN) power amplifiers (PAs) that provide state-of-the-art performance within the D-band (110-170 GHz) and G-band (140-220 frequencies. A four-stage cascode PA operates with more than 25 dB small-signal gain over 107-148-GHz band. At 120 GHz, it can deliver up to 26.4 dBm output 16.5% power-added efficiency (PAE) 26 at saturation. The combination these parameters is among best reported solid-state technology such high two circuits are able...
The piezoelectric and spontaneous polarization of wurtzite ScxAl1−xN, GaxAl1−xN, InxAl1−xN ternary compounds dramatically affects the electrical properties pseudomorphic MexAl1−xN/GaN, MexAl1−xN/AlN, MexAl1−xN/InN heterostructures devices (Me: = Sc, Ga, In), due to bound interface charges caused by gradients in at surfaces heterointerfaces. We have calculated undoped, metal polar ScxAl1−xN barrier layers (0 ≤ x 0.5) pseudomorphically grown on InN, GaN, AlN buffer layers, order compare...
Wide bandgap, high saturation velocity, and thermal stability are some of the properties GaN, which make it an excellent material for high-power, frequency, temperature applications. Given predicted wide-spread use, reliable models needed simulationbased optimization. As several application areas require devices to operate at elevated temperatures, a proper modeling dependences band structure transport parameters is highly important. We present two-dimensional hydrodynamic simulations...
The high power capabilities in combination with the low noise performance of gallium nitride (GaN) makes this technology an excellent choice for robust receivers. This paper presents design and measured results three different LNAs, which operate C-, Ku-, Ka-band. designs are realized 0.25 mum 0.15 AlGaN/GaN microstrip technology. figure is 1.2, 1.9 4.0 dB Ka-frequency band respectively. robustness LNAs have been tested by applying CW source levels 42 dBm, dBm 28 C-band, Ku-band Ka-band LNA...
This paper presents measurement results of a monolithic microwave integrated circuit (MMIC) chip set and an ultra-wideband high power amplifier (HPA) transmit module for multi-functional next-generation active electronically scanned antenna radar/electronic warfare/communication applications targeting the frequency range from 6 to 18 GHz. The reported consists driver (DA) MMIC HPA on high-power gallium-nitride process with electronic-mobility transistors. DA reaches gain 11 dB maximum output...
This letter introduces a theory which considers the effect of lossy second-harmonic terminations on voltage waveform, output power, and efficiency power amplifiers (PAs) operated in class-J mode. To this end, conventional (reactive) mode is extended to resistive-reactive with complex fundamental load impedances. The experimentally validated by performing on-wafer active load-pull measurements an AlGaN/GaN HEMT device 0.25 μm gate length total periphery 6×200 μm. measured waveforms are...
Growth of AlScN high‐electron‐mobility transistor (HEMT) structures by metal–organic chemical vapor deposition (MOCVD) is challenging due to the low pressure conventionally used precursor tris‐cyclopentadienyl‐scandium (Cp 3 Sc). It shown that electrical and structural characteristics AlScN/GaN heterostructure improve significantly using bis‐methylcyclopentadienyl‐scandiumchloride ((MCp) 2 ScCl), which has a higher allows for an increased molar flow thus growth rate (GR). HEMT...
AlScN/GaN heterostructures with their high sheet carrier density (ns) in the two-dimensional electron gas (2DEG) have a potential for high-frequency and high-power electronics. The abruptness of heterointerface plays key role 2DEG confinement, presence interlayers (AlN, AlGaN) affects ns mobility (μ) determines resistance (Rsh). suitable high-electron transistors (HEMT) without nominal AlN interlayer were grown by metal–organic chemical vapor deposition (MOCVD) characterized electrically...
Grown on a (111) high-resistivity silicon substrate, 0.1-mum gate AlInN/GaN high-electron mobility transistors (HEMTs) achieve maximum current density of 1.3 A/mm, an extrinsic transconductance 330 mS/mm, and peak gain cutoff frequency as high f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</sub> = 102 GHz, which is the highest value reported so far for nitride-based devices substrates, well any AlInN/GaN-based HEMT regardless substrate...
By combining a low damage chlorine based gate-recess etching and sophisticated technology for AlGaN/GaN depletion-mode high electron mobility transistors (HEMTs) we fabricated performance recessed enhancement-mode HEMTs. A comparative investigation of depletion- devices prepared by this technique shows excellent DC RF properties. transconductance 540 mS/mm cut-off frequencies fT 39 GHz fmax 74 were obtained 0.25 µm gate Large-signal power measurements at 2 reveal an output density 4.6 W/mm...
GaN-based high electron mobility transistors (HEMTs) with a nearly strain-free high-Al-content quaternary barrier and mobilities up to 1590 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> /Vs have been grown on 4H-SiC using molecular beam epitaxy (MBE). The processed devices 150-nm gate length exhibit dc performance maximum current density of 2.3 A/mm an extrinsic transconductance 675 mS/mm that is among the highest values reported...
A thorough approach to the investigation of GaN-based high-electron mobility transistors by device simulation is demonstrated. Due structure and material peculiarities, new comprehensive hydrodynamic models for electron are developed calibrated. Relying on this setup, three different independent technologies simulated compared. We further study pronounced decrease in transconductance <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">g</i> <sub...