Mass spectrometric studies of plasmas used for surface treatment

A considerable diversity of electrical plasma is used to modify the of mate rials which range from semi-conductors. In developing a particular process it is essential to characterise the wide range of physical and chemical pro cesses taking place, both in the body of the plasma and at the interface be tween the plasma and the workpiece whose surface is to be modifies. Among t he diagnostic tools available are mass spectrometer systems. To illustrate the range of information which may be obtained, the present paper describes the use of a quadrupole mass spectrometer in the study of a number of plas ma application. For some of these the mass spectrometer instrument included an energy filter which greatly increased the range of investigations which could be undertaken. The measurement discussed include studies of both pos itive and negative ions and of neutral species sampled from plasma.