Ar ion induced copper germanide phase formation at room temperature

Abstract

The copper germanide phase Cu₃Ge which is emerging as an alternative material for making contacts and interconnects for semiconductor industry has been produced across the interface of Cu/Ge bilayers by ion beam mixing at room temperature using 1 MeV Ar ions. The dose dependence of the thickness of the mixed region shows a diffusion controlled mixing process. The experimental mixing rate and efficiency for this phase are 5·35 nm⁴ and 10·85 nm⁵/keV respectively. At doses above 8 × 10¹⁵ Ar/cm² the formation and growth of another copper rich phase Cu₅Ge has been observed. The present theoretical models are inadequate to explain the observed experimental mixing rate.