HOEL , Virginie

For the first time, to the knowledge of the authors, GaN MESFETs on silicon substrate have been realised using low-pressure metal-organic vapour phase epitaxy. The devices demonstrate good pinch-off voltage and good breakdown voltage characteristics. A maximum extrinsic transconductance of 30 mS/mm was achieved on a 100 * 0.5 µm2 device. At a...

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This paper reports on the fabrication and characterization of AlGaN/GaN HEMTs transfered onto two different adhesive flexible tapes. Technological improvements were made during the study concerning thermal conductivity of the tapes as well as the transfer process. In this paper, it is shown that the device transferred onto the tape with higher...

Blue (Ga,In)N-based light-emitting diodes (LEDs) grown on a Si(111) substrate by metal-organic vapor phase epitaxy are transferred on a flexible tape after the Si substrate removal. Their optical and thermal behaviors are measured and compared to those of regular LEDs on Si. The light output power of the flexible LEDs is increased due to a...

This letter reports on the first demonstration of microwave power performance at 10 GHz on flexible AlGaN/GaN high-electron-mobility transistor (HEMT). A maximum dc current density of 620 mA/mm at V-GS = 0 V and a peak extrinsic transconductance of 293 mS/mm are obtained for a 2 x 50 x 0.1 mu m(2) flexible device. At V-DS = 5 V, a...

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The responsivity of AlGaN/GaN high-electron mobility transistors (HEMTs) when operating as zero-bias RF detectors in the subthreshold regime exhibits different behaviors depending on the operating temperature and gate length of the transistors. We have characterized in temperature (8–400 K) the detection performance of HEMTs with different gate...

The role that the mother substrate plays to influence the performance of InGaN/GaN-based light-emitting diodes (LEDs) onto the adhesive flexible tapes is addressed in this letter. For this purpose, the electroluminescent (EL) spectra and current density-voltage (J-V) characteristics of flexi-LEDs are studied under different convex bending...

High quality ohmic contacts were realized in order to obtain an AlGaN/GaN high electron mobility transistor (HEMT) on different substrates (Si, Al2O3, SiC). A metallization scheme based on Ti/Al/Ni/Au was used. The ohmic contacts were obtained using an optimized rapid thermal annealing (RTA) at temperature as high as 900 °C for 30 s in a N2...

This letter reports on the demonstration of microwave power performance at 40 GHz on AlGaN/GaN high-electron mobility transistor grown on silicon (111) substrate by molecular beam epitaxy. A maximum dc current density of 1.1 A.mm(-1) and a peak extrinsic transconductance of 374 mS.mm(-1) are obtained for 75-nm gate length device. At V-DS = 25...

The performance of gallium nitride transistors is still limited by technological problems often related to defects and traps. In this work, virgin AlGaN/AlN/GaN HEMTs exhibiting an anomalous DC behavior accompanied by frequency dispersion in the microwave range, both in the transconductance and output conductance, are analyzed. This anomalous...

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The performance of GaN transistors is still limited by physical and fabrication problems, mainly related to different kinds of traps. In this work, virgin transistors reveals strong low frequency dispersion both in the transconductance and output conductance, that we attribute to the presence of traps in the GaN channel and the ohmic contacts....

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