Applied Physics Letters · 2003 · 53 citations · 11 references
EngineeringElectrical EngineeringPhysicsElectronic MaterialsMicroelectronicsSemiconductor DevicesCarrier TransportCurrent-voltage CharacteristicsDevice CharacterizationSemiconductor PhysicsWide Band Gap SemiconductorsWide-bandgap Semiconductor DevicesAvalanche BreakdownAvalanche Breakdown In Wide-bandgap DevicesAvalanche FormationElectrostatic DischargeGallium Nitride (Gan) MaterialsGallium Nitride Power DevicesHigh-electron-mobility TransistorsThreshold Voltage
We investigate 50 μm gate width/0.45 μm length AlGaN/GaN high-electron-mobility transistors (HEMTs) subjected to 100 ns long current pulses that simulate an electrostatic discharge. After source–drain breakdown at around 90 V, the pulsed I–V source–drain characteristic is S shaped with an abrupt snap back to about 20 V at stress current of Istress=0.2 A. Backside interferometric thermal mapping of the HEMT shows that current filamentation accompanies the transition to the low-voltage/high-current region. The shift in transistor threshold voltage is explained by electron trapping in the buffer. It is assumed that breakdown in the regime of electrostatic discharge can be explained as an avalanche-injection event that forms a current filament through the device buffer layer.
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