Scaling of AlN/GaN HEMT for millimeter-wave power applications

International audienceIn this paper, we report on AlN/GaN HEMTs for high frequency applications. Various gate lengths have been studied as a function of the gate-drain distance in order to analyze the impact on the DC, RF and power performances. Electrical characteristics of this structure for 110 nm gate length show a maximum drain current of 1.2 A/mm, an extrinsic transconductance Gm of 400 mS/mm and a FT/Fmax of 63/300 GHz at a drain bias voltage VDS = 20V. An excellent electron confinement with a low leakage current below 10 µA/mm is achieved. Furthermore, a breakdown voltage of 55 V for GD0.5 and up to 140 V for GD2.5 are observed when using a 110 nm short gate length. Large signal characteristics at 40 GHz reveal a state-of-the-art combination of power added efficiency (PAE) (50%) with an output power density (Pout) of 3.6 W/mm at VDS = 20 V in continuous wave mode (CW) and PAE of 50% associated with a Pout of 8.3 W/mm at 40V in pulsed mode. It can be noticed that the 110 nm gate length GD0.5 showed no degradation after semi-on robustness tests and large signal measurements up-to VDS = 20V

Demonstration of GaN-on-silicon material system operating up to 3 kilovolts with reduced trapping effects

International audienceWe report on the first demonstration of low trapping effects up to 3000 V within GaN-on-silicon epitaxial layers using a local substrate removal (LSR) followed by a thick backside ultra-wide-bandgap AlN deposition. The fabricated AlGaN/GaN devices deliver low specific on-resistance below 10 mΩcm 2 together with unprecedented 3-terminal blocking voltage while substrate ramp measurements show reduced hysteresis up to 3000 V. These results pave the way for beyond 1200 V applications using large wafer diameter GaN-on-Si high electron mobility transistors

GaN-based transistors using buffer-free heterostructures for next generation RF devices

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Comparison of Two Common Maximum Power Point Trackers by Simulating of PV Generators

AbstractPower point tracker algorithms play an important role in the optimization of the power and the efficiency of a photovoltaic generator (PVG).We made the comparison between two algorithms currently implemented for the power optimization of PVG. These algorithms are based on the Perturb Observe and the Conductance-Increment methods allowing the Maximum Power Point Tracking, MPPT, principle. The study leads us to conclude that these algorithms are not well adapted for PVG exposures in very unfavorable but realistic external conditions

AlGaN/GaN High Electron Mobility Transistors with Ultra -Wide Bandgap AlN buffer

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The effect of reverse current on the dark properties of photovoltaic solar modules

AbstractForward and reverse dark current-voltage (I-V) and capacitance-voltage (C-V) characteristics of commercial amorphous silicon solar modules, were measured in order to study their performance under the influence of induced reverse currents. Maximum module surface temperatures were directly related to each value of the induced reverse current and in to the amount of current leakage respectively. Microscopic changes as a result of hot spots defects and overheating of the solar module, linked to reverse current effects, were also documented and discussed. Experimental evidence showed that different levels of reverse currents are confirmed to be a major degrading factor affecting the performance, efficiency, and power of solar modules

High frequency high breakdown voltage GaN transistors

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Procédé de variation de l'indice optique d'un guide à semi-conducteurs, guide à indice optique contrôlable et commutateur ulra-rapide

n° de priorité : FR20080004320 20080729 ; également publié en tant que : WO2010012759 (A1) 2010-04-02 ; FR2934690 (B1) 2011-02-1