IEEE Electron Device Letters · 2023 · 40 citations · 23 references
EngineeringElectrical EngineeringMaterials ScienceElectronic MaterialsSemiconductor DevicesSemiconductor MaterialsDevice ReliabilityIii-v SemiconductorsSemiconductor Device MaterialsSemiconductor ReliabilityThin Film OxidationWide Band Gap SemiconductorsBreakdown VoltageBreakdown Voltage OptimizationGallium Nitride (Gan) MaterialsGallium Nitride Power DevicesInterlayer MaterialsOxidationOxidation Defect FormationThreshold Voltage
In this letter, we apply an oxidation technique for p-GaN to a normally-off p-GaN /AlGaN/GaN HEMT to improve the threshold voltage and gate reliability. Oxygen-plasma and low-temperature Oxygen post-annealing treatment (OPAT) of p-GaN before the deposition of gate metal has introduced a 5 nm oxidation interlayer, resulting in a significant improvement in gate breakdown voltage, from 10.4 V to 20.6 V. Thanks to this interlayer, the threshold voltage of p-GaN gate HEMTs is increased from 1.9 V to 4.6 V, while an almost same on- state resistance and a higher drain breakdown voltage are obtained. Time-dependent gate breakdown measurement shows OPAT-HEMTs have a maximum on- state gate drive voltage of 9.2 V for a 10-year lifetime with a 63 % gate failure rate. In addition, a more stable threshold voltage under gate stress indicates the promising application of this technology in GaN power devices.
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