This paper presents a fast methodology for the investigation of trapping and hot-electron effects in GaN-based highelectron mobility transistors (HEMTs). The presented method is based on pulsed ID–VG measurements and electroluminescence characterization and provides a rapid and effective evaluation of the following: 1) the presence of traps in the region under the gate; 2) trapping phenomena occurring in the gate–drain access region; 3) the role of traps in limiting the maximum gate–drain electric field and the equivalent electron temperature. The method is validated by means of a split-wafer experiment carried out on GaN-based HEMTs with different gatematerials with and without passivation

In the present paper we review the most recent degradation modes and mechanisms recently observed in AlGaN/GaN (Aluminum Gallium Nitride/Gallium Nitride). High Electron-Mobility Transistors (HEMTs), as resulting from a detailed accelerated testing campaign, based on reverse bias tests and DC accelerated life tests at various temperatures. Despite the large efforts spent in the last few years, and the progress in mean time to failure values, reliability of GaN HEMTs, and millimeter microwave integrated circuits still represent a relevant issue for the market penetration of these devices. The role of temperature in promoting GaN HEMT failure is controversial, and the accelerating degradation factors are largely unknown. The present paper proposes a methodology for the analysis of failure modes and mechanisms of GaN HEMTs, based on (i) DC and RF stress tests accompanied by an (ii) extensive characterization of traps using deep level transient spectroscopy and pulsed measurements, (iii) detailed analysis of electrical characteristics, and (iv) comparison with two-dimensional device simulations. Results of failure analysis using various microscopy and spectroscopy techniques are presented and failure mechanisms observed at the high electric field values typical of the operation of these devices are reviewed

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In this paper, a further leakage reduction of AlGaN/GaN Schottky barrier diodes with gated edge termination (GET-SBDs) has been achieved by optimizing the physical vapor deposited TiN as the anode metal without severe degradation of ON-state characteristics. The optimized GET-SBD multifinger power diodes with 10 mm anode width deliver ∼4 A at 2 V and show a median leakage of 1.3 µA at 25 °C and 3.8 µA at 150 °C measured at a reverse voltage of −200 V. The temperature-dependent leakage of Si, SiC, and our GaN power diodes has been compared. The breakdown voltage (BV) of GET-SBDs was evaluated by the variation of anode-to-cathode spacing (L AC ) and the length of field plate. We observed a saturated BV of ∼600 V for the GET-SBDs with L AC larger than 5 µm. The GET-SBD breakdown mechanism is shown to be determined by the parasitic vertical leakage current through the 2.8 µm-thick buffer layers measured with a grounding substrate. Furthermore, we show that the forward voltage of GET-SBDs can be improved by shrinking the lateral dimension of the edge termination due to reduced series resistance. The leakage current shows no dependence on the layout dimension L G (from 2 to 0.75 µm) and remains at a value of ∼10 nA/mm. The optimized Au-free GET-SBD with low leakage current and improved forward voltage competes with high-performance lateral AlGaN/GaN SBDs reported in the literature.