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

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

Self-heating temperature measurement in AlInN/GaN HEMTs by using CeO2 and TiO2 micro-raman thermometers

International audienceThermal characterization of GaN-based components is an important and challenging issue that requires the measurement of the self-heating temperature of the channel, the metal contact surface and the substrate with high accuracy. This paper points out that all these thermal parameters can be measured by combining confocal Raman spectroscopy and micro-Raman thermometers. To prove these assertions, thermal resistance and Thermal Boundary Resistance (TBR) were accurately estimated experimentally. In addition, temperature measurements with TiO2 and CeO2 micro-Raman thermometers were carried out to determine which is more accurate and reliable in measuring the surface self-heating temperature of these components