High electron mobility transistor

The effect of layer structure (GaN versus AlGaN cap) and cleaning procedure prior to Sc2O3 or MgO deposition at 100° C were examined for their effects on the long-term bias-stress stability of AlGaN/GaN high electron mobility transistors (HEMTs). Surface cleaning by ...

A class-AB power amplifier was designed for an envelope tracking (ET) application. Class-AB amplifier is widely used in wireless communication systems due to the compromise between linearity and efficiency. As a power device, Cree Gallium Nitride High Electron Mobility Transistor (GaN HEMT) CGH4010F was chosen. The input and output matching networks were designed and simulated with Advanced Design System (ADS). After some optimization, the amplifier was fabricated using a Rogers RT/Duroid 5880 substrate. The amplifier together with a MAX2247 preamplifier as a driver was measured. A good agreement between the simulation and measurement results was observed. The maximum power added efficiency (PAE) is around 50 percents with the supply voltage Vsup= 10V and the maximum drain efficiency is around 75 percents with Vsup= 5V. An output power up to 42 dBm and good linearity of the output voltage with respect to the supply voltage in the range 0≪Vsup≪20V were achieved. Thus, the amplifier i...

A low noise amplifier (LNA) design operating at Xband frequency range of 8 – 12 GHz using 0.25 µm In0.7Ga0.3As/In0.52Al0.48As pHEMT is presented. The target specifications of the MMIC LNA design are then addressed, the performance constraints and compromises that arise in the design of circuit topologies, biasing networks and matching configurations are also discussed. The design and analysis of the single input single-ended output, single and double stage LNAs are presented using all of the criteria. The simulations setup successfully showed an X-band LNAs are designed to match a 50 Ω input and output impedance. The proposed design is an MMIC LNA that combines high performance with low cost and avoids expensive external components.

GaN-based microwave power amplifiers have been identified as critical components in Sandia's next generation micro-Synthetic-Aperture-Radar (SAR) operating at X-band and Ku-band (10-18 GHz). To miniaturize SAR, GaN-based amplifiers are necessary to replace bulky ...

We describe the development and issues related to fabrication, die processing, and packaging GaN-on-diamond high-electron mobility transistors into X-band amplifier modules. We perform thermal resistance measurements on these amplifiers using liquid-crystal thermography and show that they agree with theory and previously published measurements on GaN-on-diamond devices.

... RC Fitch, JK Gillespie, N. Moser, G. Jessen, T. Jenkins, R. Dettmer, D. Via, and A. Crespo Air Force Research Laboratory, Sensors Directorate, Wright-Patterson AFB, Dayton, Ohio 45433-7322 AM Dabiran, PP Chow, and A. Osinsky SVT Associates, Eden Prairie, Minnesota ...

The carbon monoxide (CO) detection sensitivities of ZnO nanorod-gated AlGaN/GaN high electron mobility transistors were measured over a range of temperatures from 25-150 °C. Once the sensor was exposed to the CO-containing ambient, the drain current, I, of the high electron mobility transistors increased due to chemisorbed oxygen on the ZnO surface reacting with CO, forming CO2 and releasing electrons

The carbon monoxide (CO) detection sensitivities of ZnO nanorod-gated AlGaN/GaN high electron mobility transistors were measured over a range of temperatures from 25-150 °C. Once the sensor was exposed to the CO-containing ambient, the drain current, I, of the high electron mobility transistors increased due to chemisorbed oxygen on the ZnO surface reacting with CO, forming CO2 and releasing electrons

This paper reviews recent advances in emission of terahertz radiation from two-dimensional (2D) electron systems in semiconductor nano-heterostructures. 2D plasmon resonance is first presented to demonstrate intense broadband terahertz emission from InGaP/InGaAs/GaAs and InAlAs/InGaAs/InP material systems. The device structure is based on a high-electron mobility transistor and incorporates the author’s original interdigitated dual-grating gates. Second topic focuses on graphene, a monolayer carbon-atomic honeycomb lattice crystal, exhibiting unique carrier transport and optical properties owing to massless and gapless energy spectrum. Coherent stimulated terahertz emission from femtosecond infrared-laser pumped epitaxial graphene is experimentally observed, reflecting the occurrence of negative dynamic conductivity and population inversion.

An investigation in to the asymmetry of the current-voltage characteristics and the local-oscillator breakthrough in anti-parallel diode sub-harmonic mixers is presented. Twenty nine bare anti-parallel diode pair circuits, have been used to identify those aspects of the diode geometry, that have a strong influence on the diode mismatch and consequently the local-oscillator breakthrough. The circuits were fabricated on a six-inch

Ultimately, the transistor power performance parameters depend on initial epitaxial material characteristics, device geometry and process parameters. This work presents a systematic research based on the design of experiment (DoE) approach by using minimal number of wafers. Factors of the DoE were few crucial process steps and process flow sequence. Different ohmic contacts alloying ambience, variation of surface treatment before SiN passivation and different sequence of the SiN passivation step in the process flow were evaluated. The optimal process flow was realized on 3" wafers. Pout of 6 W/mm, PAE 70% and 15dB gain at S- band for 0.2 mm device was measured at 30 V VD that is good aligned with state-of-the art results (3).

We investigated the emission of terahertz radiation from a doubly interdigitated grating gates high electron mobility transistor. The experiment was performed using Fourier spectrometer system coupled with high sensitive 4 K Silicon bolometer under the vacuum. The observed emission was explained as due to the excitation of the plasma waves by means of hot 2D plasmons. We also investigated the

This paper reviews recent advances in emission of terahertz radiation from two-dimensional (2D) electron systems in semiconductor nano-heterostructures. 2D plasmon resonance is first presented to demonstrate intense broadband terahertz emission from InGaP/InGaAs/GaAs and InAlAs/InGaAs/InP material systems. The device structure is based on a high-electron mobility transistor and incorporates the author’s original interdigitated dual-grating gates. Second topic focuses on graphene, a monolayer carbon-atomic honeycomb lattice crystal, exhibiting unique carrier transport and optical properties owing to massless and gapless energy spectrum. Coherent stimulated terahertz emission from femtosecond infrared-laser pumped epitaxial graphene is experimentally observed, reflecting the occurrence of negative dynamic conductivity and population inversion.

ABSTRACT AlN/GaN high electron mobility transistors (HEMTs) were irradiated with 5 MeV protons at fluences from 2×1011 to 2×1015 protons/cm2. Changes from 10% to 35% of the saturation drain current and the source-drain resistances were observed for the HEMTs exposed to the proton irradiations due to radiation-induced carrier scattering and carrier removal. Both forward and reverse bias gate currents were increased after proton irradiation and affected the drain current modulation in the positive gate bias voltage range. There was almost no gate-lag observed for the HEMT exposed to 2×1011 protons/cm2 irradiation and minimal changes for the higher doses, which implied that few surface traps were created by the high energy proton irradiation.

... SC Hung, BH Chou, CY Chang, CF Lo, KH Chen, YL Wang, SJ Pearton, Amir Dabiran, PP Chow, GC Chi, F. Ren. ... G.Steinhoff, B.Baur, G.Wrobel, S.Ingebrandt, A.Offenhauser, A.Dadgar, A.Krost, M.Stutzmann, and M.Eickhoff, “Recording of cell action potentials with AlGaN/GaN ...

ABSTRACT We investigated the contact resistance of a non-alloyed Ti/Pt/Au ohmic electrode to obtain thermally stable source–drain resistance of cryogenically cooled In0.75Ga0.25As/In0.52Al0.48As high electron mobility transistors (HEMTs) fabricated on (411)A-oriented InP substrates by molecular beam epitaxy. A contact resistance of 0.26Ωmm, which strongly depended on InAlAs spacer and barrier layers, was achieved at 16K (25% below the value at 300K) for the non-alloyed Ti/Pt/Au ohmic electrode formed on the In0.75Ga0.25As/In0.52Al0.48As HEMT structure with 3-nm-thick InAlAs spacer and 10-nm-thick InAlAs barrier layers. For a 195-nm-gate HEMT, we achieved a maximum transconductance (gm) of 2.25S/mm at 16K (26% above the value at 300K), which, to our knowledge, is one of the highest values for HEMTs ever reported. This extremely high gm was attributed to not only 33% lower source–drain resistance (0.18Ωmm at 16K) because of thermally stable and low contact resistance but also 19% lower transit time under the gate (0.39ps at 16K) because of phonon scattering suppression compared with the 300K values.

Nanometric InGaAs-based High Electron Mobility Transistors (HEMTs) have been shown experimentally to generate and detect THz radiation. The observed phenomena can be attributed to the presence of plasma waves inside the transistor channel. To investigate these oscillations we have performed Monte Carlo simulations of InGaAs homogeneous channels of different length and thickness. To detect the presence of plasma waves we

Reliability in GaN based devices still motivates numerous studies because the involved degradation mechanisms are different from that in III-V narrow bandgap devices. Direct investigations on high electron mobility transistors (HEMT) are performed with low frequency noise (LFN) measurements and pulsed electrical characterization. Undoped AlGaN/GaN devices grown on silicon substrate are stressed at a junction temperature of 175°C. Gate-lag and drain-lag measurements method have been performed versus different quiescent bias points and under different pulse conditions. This method allows the discrimination of each lag phenomenon as well as the thermal contribution. Thus it is possible to track and model the trapping mechanisms versus bias conditions. This electrical modelling is completed with LFN measurements, which is largely used for reliability investigations.

We experimentally and analytically investigated the possibility of injection locked oscillation in a plasmon-resonant dual-grating-gate high-electron mobility transistor to the difference terahertz frequency component of photomixed dual CW laser irradiation. Although the perfect injection locking has not yet been obtained the device model we newly formulate will lead to find practical solutions of successful operation.