A TOF-SIMS Investigation of the Corrosion-Induced Failure Via Grain Boundaries in Polycrystalline Materials

Polycrystalline semiconductor or metal materials are characterized with numerous grain boundaries between neighboring grains. The grain boundaries show a high degree of mismatch of grain orientation and a less efficient atomic packing. Aggressive ions can diffuse much more easily within grain boundaries; rendering the zone susceptible to oxidation and corrosion, which are one of the root causes for electronic device failures. Therefore, revealing the compositional distribution of grain boundaries can help researchers better understand and improve the chemical, physical and electrical properties of materials. This paper mainly focuses on material characterization of the corroded material, providing useful methods for physical failure analysis in real devices which will be discussed in our future work. Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) is one of the most sensitive techniques for materials analysis. One of its powerful capabilities is to provide 3D images of testing material, demonstrating elemental distribution and microstructure of polycrystalline materials. In this work, common polycrystalline materials used in semiconductors (polysilicon) and metal alloys (304 steel) were studied. TOF-SIMS 3D imaging was used to monitor the diffusion path of moisture and corrosive ions via the grain boundaries. The results indicate that the grain boundaries are vulnerable to attacks of moisture and corrosive ions (CI).