TEM SPECIMEN HEATING DURING ION-BEAM THINNING - MICROSTRUCTURAL INSTABILITY

Experimental results are prsented to show that energy input to Au/Si interface specimens by the particle beam during 'ion' thinning is sufficient to rasie the specimen temperature to a somewhat surprising 370 degree C, and to cause microstructural instability in the form of eutectic melting and interface migration. By analysis of various possible thermal energy dissipation mechanisms it was shown that poor thermal conduction through the specimen support was responsible. The heating effects can be eliminated in the present case by the somewhat inconvenient use of a low-temperature, cooled specimen support. It is suggested that most such heating effects can be more conveniently eliminated by use of specimen supports made from high thermal conductivity materials. These measures to reduce specimen heating will become more important as particle beam thinning is increasingly applied to a wider range of less refractory materials.