Formation of polycrystalline silicon germanium/HfO2 gate stack structure using inductively coupled plasma etching

Abstract

The amount of notching formed by ICP etching of poly-SiGe was controlled. A notch gate that can be used for short channel devices of a gate length smaller than 65 nm was formed. Notching was controlled by varying the etching process parameters of inductive power, rf bias power, and pressure, as well as by varying the Ge concentration in poly-SiGe. Etching of HfO2 was strongly dependent on the sputtering by ion bombardment. By controlling the etching selectivity of poly-SiGe to HfO2 with the change in the rf bias power in the presence of a small amount of O in HBr plasmas, the processing feasibility of the formation of a poly-SiGe/HfO2 gate stack using ICP etching was demonstrated.