Nanoscale Research Letters · 2018 · 13 citations · 41 references
EngineeringMaterials SciencePhysicsElectronic MaterialsSemiconductor DevicesSemiconductor MaterialsDopingMetal-semiconductor ContactsMetalsPlasma-surface InteractionsSemiconductor Device MaterialsSemiconductor InterfacesConduction BandContact ResistanceFermi Level PinningMetal-semiconductor InterfacesOhmic ConductionOhmic ContactsPlasma TreatmentResistivity
We investigate the metal-insulator-semiconductor contacts on n-Ge utilizing a ZnO interfacial layer (IL) to overcome the Fermi-level pinning (FLP) effect at metal/Ge interface and reduce the barrier height for electrons. A small conduction band offset of 0.22 eV at the interface between ZnO and n-Ge is obtained, and the ZnO IL leads to the significant reduced contact resistance ( R c ) in metal/ZnO/n-Ge compared to the control device without ZnO, due to the elimination of FLP. It is observed that the argon (Ar) plasma treatment of ZnO can further improve the R c characteristics in Al/ZnO/n-Ge device, which is due to that Ar plasma treatment increases the concentration of oxygen vacancy V o , acting as n-type dopants in ZnO. The ohmic contact is demonstrated in the Al/ZnO/n-Ge with a dopant concentration of 3 × 10 16 cm −3 in Ge. On the heavily doped n + -Ge with a phosphor ion (P + ) implantation, a specific contact resistivity of 2.86 × 10 − 5 Ω cm 2 is achieved in Al/ZnO/n + -Ge with Ar plasma treatment.
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Anderson Janotti, Chris G. Van de Walle · Applied Physics Letters · 2005 · 1.2K citations
Fermi-level pinning and charge neutrality level in germanium
A. Dimoulas, Polychronis Tsipas, A. Sotiropoulos et al. · Applied Physics Letters · 2006 · 605 citations