The precise determination of the relative concentration of negative ions is very important for
the optimization of magnetron sputtering processes, especially for those undertaken in a
multicomponent background produced by adding electronegative gases, such as oxygen, to
the discharge. The temporal behavior of an ion acoustic wave excited from a stainless steel
grid inside the plasma chamber is used to determine the relative negative ion concentration
in the magnetron discharge plasma. The phase velocity of the ion acoustic wave in the …