Mass and energy analysis of incident ions to substrate during deposition by hollow cathode discharge

Abstract

Direct measurement of mass and energy of incident ions by using an ion detector equipped with a cylindrical‐mirror‐type ion energy analyzer and a quadrupole mass spectrometer are carried out to reveal that physical vapor deposition by the HCD process produces a great deal of metal ions. Chromium is evaporated by an electron beam of 50 V×70 A and in argon at 0.1 Pa. Relative intensity ratio of Cr+: Ar+: Cr++ is typically 80: 16: 4, and the average ion energy of Cr+ is several to ten eV with the substrate voltage the same as that of the chamber. Analysis of incident ions during the HCD reactive evaporation of chromium by introducing acetylene or nitrogen is also carried out. For both cases, Cr+ occupies over 90% or higher; the rest is Ar+ and C2H2+ for backfilled Ar plus acetylene or Ar+ and N2+ for backfilled Ar plus nitrogen. Gas analysis during chromium evaporation reveals a marked decrease in gases including backfilled argon, acetylene, or nitrogen due to an evaporation gettering in the presence of the electron beam from the HCD gun.