Quantitative depth profiling of thin layers

Foundations of sputtering profile evaluation are discussed, which allow the conversion of a measured sputtering profile, I = f(t), to a true element concentration profile celem. = f(z), or in special cases to a phase profile cphase = f(z). As a relatively new method for quantitative thin film analysis, glow discharge optical emission spectrometry (GDOES) has the special advantage of a narrow depth resolution function. Growing sputter crater profiles can be eliminated by a deconvolution algorithm, as is shown for TiN/TiAlN multilayers. The sputtering rate as a function of depth may be also deduced by a special wedge crater profile, which is sputtered into the material by an ion beam under suitable beam control. Further information on a phase depth profiling may be obtained by principal component analysis, as is discussed for AES and XPS investigations of P implanted Ti. A special technique of cross section imaging of thin layers is the analytical TEM, which allows the parallel investigation of microstructure and element distribution, as illustrated for a Cr-Fe multilayer.