Self-limiting processes in thermal atomic layer etching of nickel by hexafluoroacetylacetone
Abdulrahman H. Basher, Ikutaro Hamada, Satoshi Hamaguchi
Abstract
Abstract In thermal atomic layer etching (ALE) of Ni, a thin oxidized Ni layer is removed by a hexafluoroacetylacetone (hfacH) etchant gas at an elevated surface temperature, and etching ceases when a metallic Ni surface appears (self-limiting step). However, atomistic details of the self-limiting step was not well understood. With periodic density-functional-theory calculations, it is found that hfacH molecules barrierlessly adsorb and tend to decompose on a metallic Ni surface, in contrast to the case of a NiO surface, where they can form volatile Ni(hfac) 2 . Our results clarify the origin of the self-limiting process in the thermal ALE.
Topics & Concepts
Etching (microfabrication)NickelLimitingNon-blocking I/OMetalAdsorptionThermalSelf limitingLayer (electronics)Inorganic chemistryMaterials scienceIsotropic etchingChemistryPhysical chemistryNanotechnologyMetallurgyThermodynamicsOrganic chemistryCatalysisDermatologyPhysicsMechanical engineeringMedicineEngineeringSemiconductor materials and devicesPlasma Diagnostics and ApplicationsMolecular Junctions and Nanostructures