APPLICATION OF GLOW-DISCHARGE MASS-SPECTROMETRY WITH LOW MASS RESOLUTION FOR IN-DEPTH ANALYSIS OF TECHNICAL SURFACE-LAYERS

A low resolution glow discharge mass spectrometry system with a quadrupole has been applied to the surface and in-depth analysis of conducting solids. The ion source utilizes a Grimm-type obstructed discharge that is particularly suited to this type of application, as is known from the application of glow discharges in atomic emission spectrometry. Flat crater profiles can be obtained in the sputter process by maintaining a material-dependent critical burning voltage. In basic studies of Cr-Ni multilayer systems, a depth resolution of about 10 nm could be achieved. A procedure has been developed for conversion of the registered intensity versus time profiles into the desired concentration versus depth profiles. This procedure has been applied to the analysis of technical surface layers with a thickness of from 30 nm to 10 mum. With a penetration rate of up to 0.1 mum s-1, the technique is particularly suitable for the analytical characterization of surface layers with a thickness in the micrometer region.