A5035890444- Radio Frequency Integrated Circuit Design
- Semiconductor Quantum Structures and Devices
- GaN-based semiconductor devices and materials
- Semiconductor materials and devices
- Microwave Engineering and Waveguides
- Advancements in Semiconductor Devices and Circuit Design
- Semiconductor Lasers and Optical Devices
- Semiconductor materials and interfaces
- Electromagnetic Compatibility and Noise Suppression
- 3D IC and TSV technologies
- Advanced Antenna and Metasurface Technologies
- Silicon Carbide Semiconductor Technologies
- Photonic and Optical Devices
- Integrated Circuits and Semiconductor Failure Analysis
- Antenna Design and Analysis
- Advanced Power Amplifier Design
- Silicon and Solar Cell Technologies
- Advanced Semiconductor Detectors and Materials
- Transition Metal Oxide Nanomaterials
- Thermal Radiation and Cooling Technologies
- Acoustic Wave Resonator Technologies
- Nanowire Synthesis and Applications
- Thin-Film Transistor Technologies
- Copper Interconnects and Reliability
- Electrostatic Discharge in Electronics
University of Manchester
2014-2023
University of L'Aquila
2020
University of Utah
2015
Manchester Academic Health Science Centre
2006
King's College Hospital
1997-2005
King's College London
1994-2003
University of London
1994-2002
University College London
1996
University of Sussex
1985-1991
Middlesex University
1989-1991
A Caughey–Thomas-like mobility model with temperature and composition dependent coefficients is used in this work to describe the dependence of electron hole mobilities on temperature, doping concentration, alloy composition. Appropriate parameter sets are given for a large number III–V binary ternary compounds, including: GaAs, InP, InAs, AlAs, GaP, Al0.3Ga0.7As, In0.52Al0.48As, In0.53Ga0.47As, In0.49Ga0.51P. Additionally, physically justifiable interpolation schemes suggested find various...
The dielectric properties of ten rat tissues at six different ages were measured 37 °C in the frequency range 130 MHz to 10 GHz using an open-ended coaxial probe and a computer controlled network analyser. results show general decrease with age. trend is more apparent for brain, skull skin less noticeable abdominal tissues. variation age due changes water content organic composition percentage certain 30 70 day old rats cellular phone frequencies have been tabulated. These data provide...
Thermal characterizations and modeling have been carried out on a 0.15 μm× (4×50) μm gate GaN-/SiC-based high-electron-mobility transistor varying the temperature from -40 °C to 150 frequency up 50 GHz using on-wafer measurements. The thermal behavior of dc parameters along with resistance estimation equivalent circuit cutoff maximum frequencies were analyzed reported single device. coefficients these presented deduced influence effects device parameters. These results are important for...
Shifts in the threshold voltage V T subject to temperature AlGaN/GaN-based high-electron-mobility transistors (HEMTs) grown on silicon carbide substrate are reported. Variation of with drain–source and is investigated, including experimental characterization, modelling analysis. Possible parameters that affect Schottky barrier height device, along trap-assisted phenomena, aluminium concentration polarization fields depending dielectric, were studied. The shift positively temperature, a zero...
Temperature-dependent dc and small-signal analysis have been carried out on <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.5~\mu \text{m} \,\, \times 200$ </tex-math></inline-formula> - notation="LaTeX">$\mu \text{m}$ AlGaAs/InGaAs pseudomorphic high-electron mobility transistor over the temperature range from −40 °C to 150 by on-wafer S-parameter measurements up 50 GHz. The thermal behavior of...
This paper investigated the temperature effects on performance of AlGaN/GaN high electron mobility transistor (HEMT) with a 150 nm and 250 gate length SiC substrate over range −40 to °C including experimental characterization, modelling analysis by on-wafer measurements up 50 GHz. All DC small signal parameter variations ambient same set devices have been reported for first time. The coefficient all parameters as well f t max were reported. Some extracted equivalent circuit theoretical data...
An improved HBT small-signal parameter extraction procedure is presented in which all the equivalent circuit elements are extracted analytically without reference to numerical optimization. Approximations required for simplified formulae used routine revised, and it shown that present method has a wide range of applicability, makes appropriate GaAs InP-based single double HBTs. Additionally, new developed extract total delay time HBTs at low frequencies, need measure h/sub 21/ very high...
Newly developed transmission-line structures using the great flexibility of three-dimensional multilayer technology have been designed and fabricated. In this paper, we demonstrate that monolithic microwave integrated circuit (MMIC) coplanar waveguide transmission lines with a wide range characteristic impedances can easily be technique. Furthermore, implementation avoid well-known current crowding effects on conductor edges minimizing dissipation loss. The system three layers metals two...
Detailed spectral response (SR) modeling for heterojunction bipolar phototransistors (HPTs) is presented in this work. All the related physical parameters are taken into account resolution of photogenerated excess minority carrier continuity equations active layers HPT. The layer dependence optical flux absorption profile at near-bandgap wavelengths also investigated and its generalization as a single-exponential has been refuted HPTs based on GaAs material systems (InGaP-GaAs/AlGaAs-GaAs)....
The authors report what they believe to be the first successful fabrication of an InGaAs/GaAs vertical-cavity surface emitting laser (VCSEL) using optically transparent indium-tin-oxide (ITO) ohmic contacts p- and n-type regions laser. Threshold current densities Jth are similar those lasers fabricated from same wafer conventional contacts.
An optically transparent emitter InP/InGaAs heterojunction phototransistor (HPT) fabricated using Indium Tin Oxide (ITO) as the ohmic contact is presented for first time; these devices show similar electrical characteristics to their opaque counterparts and enhanced optical responsivities (5.4 A/W at 780 nm wavelength). Measured spectral response suggests of up 30 22 /spl lambda/=1310 1550 respectively.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML"...
Ion-implanted GaAs MESFETs with transparent indium tin oxide (ITO) gate electrodes have been fabricated using both sputtered and evaporated ITO gates. High-quality films transparency greater than 90% low sheet resistance of 8 Ω/□ used in the fabrication RF Transparent-gate FETs also thermally which shown excellent electrical device performance comparable to conventional MESFET. The optical responsivity these devices is about 4.5 A/W for a radiation wavelength 6328 Å. Fabrication details are...
This paper focused on nonlinear distortion modeling and characterization of AlGaN/GaN HEMT SiC substrate using a two-tone intermodulation measurement. The variation Taylor series coefficients with temperature: linear terms (G <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</sub> G xmlns:xlink="http://www.w3.org/1999/xlink">ds</sub> ), xmlns:xlink="http://www.w3.org/1999/xlink">m2</sub> , xmlns:xlink="http://www.w3.org/1999/xlink">m3</sub>...
Two novel types of coupled line structures have been realized on GaAs monolithic microwave integrated circuits to obtain 90° couplers operating at a center frequency 24 GHz. Both the are made up either two or three conductive layers improve coupling. The aim is achieve compact with smaller aspect ratios and decrease losses due field crowding edges. achieved good matching simulation carried out electromagnetic simulator em (a trademark Sonnet Software Inc.).
A technique to fabricate novel multilayer monolithic microwave integrated circuit (MMIC) structures using polyimide as insulating dielectric layer is described. The formation, curing and dry etching processes are investigated in an attempt obtain high quality layers suitable for MMIC applications. By employing this technique, design routings become much easier conventional microstrip transmission lines lumped passive components can be realised with effective use of the substrate material. In...
Temperature influence on the device behavior has been carried out AlGaAs/InGaAs/GaAs-based pseudomorphic high-electron mobility transistor fabricated in multilayer 3-D monolithic microwave integrated circuits technology over multibias operation condition. The thermal effect dc and RF, small-signal (up to 40 GHz) large-signal parameters, including third-order intercept points as well linear intermodulation output power performance at 4 GHz were analyzed reported for first time. In addition,...
Photoresponse of GaAs-based double-heterojunction phototransistors (DHPTs), in surface-illuminated orientation, has been analyzed with a modified small-signal model. The effect incident optical illumination on various intrinsic parameters discussed for In <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.49</sub> Ga xmlns:xlink="http://www.w3.org/1999/xlink">0.51</sub> P/GaAs N <sup xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> p...
The anomalies and the threshold voltage shifts in GaN GaAs based high electron mobility transistors over temperature were reported analyzed using on wafer measurements. Discrepancies are noticed; most conspicuously that thermal trends of two device technologies utterly contrasting. This anomaly extends for other parameters devices such as sheet carrier densities two-dimension gas. In addition barrier inhomogeneities band offset semiconductor heterojunction with provides some valuable...
Temperature effect modelling and analysis have been carried out on 0.25 μm gate length AlGaN/GaN HEMT grown SiC substrate over the temperature range from − 40 to 150°C by on-wafer S-parameter measurements up 50 GHz. The behaviour of DC equivalent circuit parameters including f <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">t</inf> xmlns:xlink="http://www.w3.org/1999/xlink">max</inf> were analyzed. results provide some valuable insights for...
Thermal influence on S22 kink behavior has been carried out a 0.15 μm gate length AlGaN/GaN/SiC high electron mobility transistor over wide range of temperature. The size and the shape effect (KE) in terms biasing temperature have evaluated. main finding is that studied device affected by two kinks: first one appears at approximately 19 GHz then second about 43 GHz. impact intrinsic circuit parameters phenomena inspected to assess their contribution. In addition, new procedure proposed...