MEASUREMENT OF SPUTTERED ATOM ENERGY BY OBSERVATION OF DOPPLER BROADENING OF EMISSION-LINES FROM PLASMA

We have developed a method of measuring sputtered atom energy by observing the Doppler broadening of emission lines from plasma using a high resolution (0.72 pm for lambda = 400 nm) Fabry-Perot interferometer. We studied atoms in sputtered CoCr film, a well-known perpendicular magnetic recording medium. We were able to measure the energy distribution of chromium atoms, which have no nuclear spin, by observing the Doppler broadening of the emission line which transits to a metastable state. We could not, however, measure that which transits to a ground state because of self-absorption, and could not perform the measurement for cobalt atoms. Cobalt atoms have nuclear spin, which causes overlapped cobalt hyperfine-split lines. We found that the Doppler broadening depends on the sputtering conditions, including sputtering frequency, argon gas pressure and sputtering power.