Journal of Applied Physics · 1985 · 126 citations · 33 references
EngineeringElectrical EngineeringMaterials ScienceMicroelectronicsSemiconductor DevicesSemiconductor MaterialsCarrier TransportDevice ModelingOxide SemiconductorsSemiconductor InterfacesSemiconductor PhysicsSilicon MaterialsCharge InjectionCharge Injection DevicesElectron Impact IonizationGate Oxide InterfacesGate Oxide Thickness EffectsGate OxidesOxide ChargeSilicon
The exact mechanism of ionization in SiO₂—whether band‑to‑band or trap‑assisted—is still unclear. The study investigates bulk positive charge generation in SiO₂ layers of MOS devices under high electric fields and charge injection. An impact ionization–recombination model, incorporating spatial and field‑dependent ionization probability, explains the charge dynamics and distribution across oxide thicknesses. Bulk positive charge of similar nature also forms in Al gate oxides, though it was sometimes obscured by larger interfacial charges in prior studies.
The generation of a bulk positive charge in SiO2 layers of silicon gate metal-oxide-silicon (MOS) devices, under the conditions of high-field and charge injection is studied. The time dependence of the positive charge and its spatial distribution as a function of the oxide thickness and electric field are all consistent with an impact ionization-recombination model which takes into account both the spatial and the field dependence of the ionization probability. The nature of the ionization, either band-to-band, or traps ionization, is still unknown. Bulk positive charge of the same nature is also formed in Al gate oxides. Nevertheless, it was not always observed in previous works since a much larger Si-SiO2 interfacial positive charge is also generated in these samples.
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Electron trapping in SiO2 at 295 and 77 °K
Donald R. Young, E. A. Irene, D. J. DiMaria et al. · Journal of Applied Physics · 1979 · 254 citations