Applied Physics Letters · 2007 · 270 citations · 14 references
EngineeringMaterials EngineeringMaterials ScienceElectronic MaterialsSemiconductor DevicesSemiconductor MaterialsAtomic Layer DepositionMos CapacitorsSemiconductor Device MaterialsSemiconductor InterfacesSemiconductor SurfacesSurface PassivationCapacitance-voltage CharacteristicsGate Oxide InterfacesHigh-k DielectricsInterface StatesPassivationPassivation LayersPassivation MechanismsPassivation Techniques
In search of a proper passivation for high-k Ge metal-oxide-semiconductor devices, the authors have deposited high-k dielectric layers on GeO2, grown at 350–450°C in O2. ZrO2, HfO2, and Al2O3 were deposited by atomic layer deposition (ALD). GeO2 and ZrO2 or HfO2 intermix during ALD, together with partial reduction of Ge4+. Almost no intermixing or reduction occurs during Al2O3 ALD. Capacitors show well-behaved capacitance-voltage characteristics on both n- and p-Ge, indicating efficient passivation of the Ge∕GeOx interface. The density of interface states is typically in the low to mid-1011cm−2eV−1 range, approaching state-of-the-art Si∕HfO2∕matal gate devices.
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