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Nitrides of refractory metals are investigated as diffusion barriers for Cu metallization. The composition, thermal stability and inter diffusion in layered systems are characterized by depth profile analysis. For the quantification of depth profiles determination of sensitivity factors is essential. For nitrogen and other light elements matrix specific standards are often not available and compound standards are used for calibration. We have investigated the systems Ta–N and Ta–Si–N and for comparison Cr–N by means of Auger electron spectrometry (AES) and glow discharge optical emission spectrometry (GDOES). A non-linear calibration curve for the N/Cr intensity ratio was observed with GDOES in the Cr–N-system, probably caused by self-absorption of the Cr line. [ABSTRACT FROM AUTHOR]

Present day ultra-large scale integration technology exploits the variation of material properties on a nanometer scale and requires analytical methods that can provide adequate characterisation at that level. An overview is given of the consequences for SIMS depth profiling of this ongoing trend to smaller dimensions. After a general introduction to the technique, the necessity to use sub-keV primary ion impact energies is explained on the basis of the depth resolution function, which describes the profile distortion accompanying sputtering. Then the implications of lower energies are discussed by describing recent instrumental developments. Next the existing quantification schemes, for the conversion of a time-dependent secondary ion’s signal intensity to a true in-depth concentration distribution, are treated. These are limited to steady-state erosion conditions, i.e. effectively exclude the pre-equilibrium regime and transition regions around interfaces or associated with the onset of bombardment induced topography development. In advanced devices such areas often constitute an indispensable functional part and therefore reliable answers must be provided there too. The merits and limitations of the few proposed options for absolute quantification at all depths will be critically examined in the final part of this review. [ABSTRACT FROM AUTHOR]