Three-Terminal Junctions operating as mixers, frequency doublers and detectors: A broad-band frequency numerical and experimental study at room temperature

The frequency response of nanometric T- and Y-shaped three-terminal junctions (TTJs) is investigated experimentally and numerically. In virtue of the parabolic down-bending of the output voltage of the central branch obtained at room temperature under a push-pull fashion input, we analyze: the low-frequency performance (<1 MHz) of TTJs operating as mixers, their RF capability as doublers up to 4 GHz and detection at 94 GHz. Special attention is paid to the impedance matching and cut-off frequency of the measurement set-up. The numerical study is done by means of Monte Carlo simulations. We illustrate the intrinsic functionality of the device as frequency doubler or rectifier up to THz. The role of the width of the central branch on the highfrequency response is also explored, finding different cut-off frequencies for doubling and detection as a consequence of the diverse working principles of both mechanisms and the particular geometry of the TTJs.ROOTHz (FP7-243845

High Power Performances of AlGaN/GaN HEMTs On Sapphire Substrate At F=4GHz

The high potential at microwave frequencies of AlGaN/GaN HEMTs on sapphire substrate for power application has been demonstrated in this paper. An output power density close to 5W/mm has been measured on a 2x25x0.5µm² HEMT on sapphire substrate. This result is very interesting because the devices have not been passivated. At present time, it is the best power result in Europe on this substrate

Characterisation in 26 - 40 GHz band of HEMT's with an active load pull system

An active load pull system is presented for measuring devices from 50 um to 1 mm gate width in Ka Band. It permits in a first configuration to measure the scattering parameters in small- and large-signal conditions. In the other configuration, it permits to extract all gains, power levels, impedances of interest, average currents and efficiencies for a given device, even for very large gate width. It can scan automatically the interesting area of the Smith chart. The system protects the tested devices because the impedance is presented at the output of the device only if the gate current is lower than a fixed value

Power improvement of AlGaAs/InGaAs PHEMTs by using low gamma radiation dose

International audienc

Time-resolved self-heating temperature measurements of AlInN/GaN HEMTs using CeO2 Raman micro-thermometers

International audienceThe DC and RF electrical performance and reliability of GaN-based transistors depend on their thermal behavior. Therefore, measuring the self-heating temperature of these devices under real operating conditions with high accuracy is an important and challenging issue. For these reasons, we present a time-resolved thermometry technique to measure transient self-heating temperatures in semiconductor components by combining conventional Raman spectroscopy and CeO2 Raman micro-thermometers. Thus, the experimental GaN volumetric and surface self-heating temperatures measured for biased AlInN/GaN HEMTs in both DC and pulsed regime are reported with a submicrometer spatial resolution and a temperature resolution of about 5 °C. Likewise time-resolved self-heating temperature of drain contact surface has also been studied

Power improvement of AlGaAs/InGaAs PHEMTs by using low gamma radiation dose

International audienc

Trapping Effect in AlInN/GaN HEMTs: A Study Based on Photoionization and Pulsed Electrical Measurements

International audienceThe aim of this article is to detect electron traps in AlInN/GaN transistors operating at room temperature by combining pulsed electrical measurement with photoionization techniques to rapidly assess their activation energies and time constants. In addition, this technique can also reveal the presence of electron traps that cannot be observed by using pulsed measurements alone. Thus, two electron traps were identified including a deep level whose origin could be related to dislocations in the GaN buffer existing in the devices. At the same time, this study has shown that the time constants of these electron traps are inferior to 400 ns and that the electrical behavior of the components is also degraded by the presence of surface states with a time constant of 4 μ s. Moreover, these two traps are at the origin of the gate lag effects observed during the pulsed electrical characterization of the AlInN/GaN high electron mobility transistors (HEMTs). Likewise, a negative output conductance induced by a trapping effect has been put forward