AES and SAM microanalysis of structure ceramics by thinning and coating the backside

The preparation of thin specimens from bulk ceramic materials and coating the reverse side of the specimens with conductive material was used effectively to minimize the charging effects on ceramic surfaces during AES and Scanning Auger Microscopy (SAM) analysis. The technique allowed AES and SAM analysis to be carried out with analysis areas of a few tens of nanometres in size. The decrease of surface charging by this technique results from the transition of a primary electron beam interaction volume (VA) from an insulating region (VI) to the conductive coating region (VC) after thinning of the specimens. This reduces the number of electrons remaining in the insulating region and thus surface charging is reduced. Three structure ceramic bulk materials were prepared using this thinning technique and analysed by high-energy resolution AES and SAM: (Y, La)-doped silicon nitride; Dy-doped Sialon; and alumina composite reinforced with silicon carbide whiskers. It is observed clearly in the grains of silicon nitride and the Sialon system that the kinetic energies of Si LVV and Si KLL shift to 84 and 1613 eV, respectively, and Si LVV is shifted further to ∼80 eV in the intergranular phases of the silicon nitride system as the nitrogen atoms are replaced by oxygen to produce N–Si–O bonding. Nitrogen was detected at the interfaces of alumina and the silicon carbide whiskers. The difference and distribution of composition in solid solution phases and intergranular phases are shown also in the SAM images and AES spectra. Copyright © 2001 John Wiley & Sons, Ltd.