Radiofrequency glow discharge time of flight mass spectrometry for thin films analysis: Pulsed mode versus continuous mode

Direct surface and depth profiling chemical analysis of advanced multilayer materials demands "multi-dimensional" knowledge, including simultaneous elemental and molecular information. Pulsed radiofrequency glow discharges (pulsed rf-GDs) with detection by time of flight mass spectrometry (TOFMS) provide direct chemical information from a great variety of materials in a fast and easy way. On the other hand, the temporal distribution of the applied power in pulsed rf-GDs produces three main regimes in the discharge (prepeak, plateau and afterpeak) with different mechanisms of ionization. As a result, the quasi-simultaneous acquisition of elemental and molecular ions (at the different pulse regimes) becomes a real possibility when coupling the GD ion source to a fast TOF mass spectrometer.