Direct Comparison of Auger, SIMS, and Proton Resonance Profiling for Reliability Studies

Uniformly prepared samples have been used for comparison of profiles using three techniques. Proton resonance is nondestructive and provides the best depth resolution at or near the surface. PRP was used as a quantitative standard for total number of particles and for absolute depth. However, the ability of PRP to resolve fine structure beyond the first few hundred angstroms is inferior to SIMS and AES. Proton Resoance Profiling is not expected to be widely used as a profiling technique because of the capital equipment costs and the limited number of impurity-host combination. However, this technique can be utilized to evaluate and calibrate other diagnostic techniques in a quantitative manner. Auger Electron Spectroscopy is a nondestructive surface analysis technique and is most sensitive to surface impurities. In order to profile with AES, the surface must be sputtered, thus destroying the sample. The limits of sensitivity are on the order of 0.1 atomic 7. Thus, the SIMS and PRP techniques are more sensitive for depth profiling of dopants and trace impurities. AES capital equipment costs, however, are signifi´cantly lower than the other two techniques and many surface oriented reliability problems can be effectively examined by AES. Secondary Ion Mass Spectrometry is the most sensitive of the techniques compared in this work and is capable of semiquantitative analysis of a wide range of dopants and impurities relevant to reliability studies. However, as with AES profiling the material is sputtered away thus destroying the sample.