Applied Physics Letters · 2002 · 103 citations · 10 references
Natural SciencesMaterials EngineeringMaterials ScienceElectronic MaterialsSemiconductor DevicesSemiconductor MaterialsAmorphous MaterialsAmorphous SolidsAtomic Layer DepositionDielectricsSemiconductor Device MaterialsX-ray DiffractionAmorphous Phase StabilityAmorphous Thin FilmsAtomic Layer Deposition PrecursorsCrystallizationGate Dielectric EngineeringGate DielectricsThermal StabilityX-ray Diffraction Analysis
We demonstrate significantly improved thermal stability of the amorphous phase for hafnium-based gate dielectrics through the controlled addition of Al2O3. The (HfO2)x(Al2O3)1−x films, deposited using atomic layer deposition, exhibit excellent control over a wide range of composition by a suitable choice of the ratio between the Al and Hf precursor pulses. By this method, extremely predictable hafnium aluminate compositions are obtained, with Hf cation fractions ranging from 20% up to 100%, as measured by medium energy ion scattering. Using x-ray diffraction, we show that (HfO2)x(Al2O3)1−x films with Hf:Al∼3:1 (25% Al) remain amorphous up to 900 °C, while films with Hf:Al∼1:3 (75% Al) remain amorphous after a 1050 °C spike anneal.
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Ion beam crystallography of surfaces and interfaces
J. F. van der Veen · Surface Science Reports · 1985 · 602 citations