Permalloy stoichiometry by nuclear backscattering

Abstract

The high mass-resolution capability of nuclear backscattering spectrometry with 4.7 MeV 4He ion beams has been used to study the stoichiometry of thin permalloy (NiFe) films. For film thicknesses ≤, 250 A ̊ , the backscattering signals from isotopes of Ni and Fe are sufficiently resolved to allow accurate determination of stoichiometry; the Ni fraction can be determined to better than ± 1%. Studies of the dependence of NiFe film stoichiometry on deposition method, film thickness and oxygen contamination indicate that NiFe stoichiometry is independent of film thickness and oxygen contamination, but electron-beam evaporation produces films slightly richer in Ni than does sputtering.