As the role of transmission electron microscopy (TEM) in materials research as well as in device development increases, the preparation of satisfactory TEM samples becomes more important.
The cross-sectional TEM specimens of $WSi_x/poly-Si/SiO_2/Si$, Cu/TiN/Ti/Si were made by the sector speed control ion milling technique. The differential thinning problems could be effectively mitigated when the sector speed control angle and the ion beam incidence angle were optimized for each heterostructure. The atomic force microscopy study on the surface topography of the cross-sectional specimens after ion-milling provided quantitative information about the effects of the sector speed control angle variation. But it was found that the modified ion milling technique was perfect preparation technique and some problems remained.
We made the cross-sectional TEM specimens of $WSi_x/poly-Si/SiO_2/Si$ using the Tripod polishing technique. We could confirm that the differential thinning problems remained at ion-milled specimens were excellently mitigated at Tripod polished specimens and the artifact-free specimens could be prepared by Tripod polishing technique from AFM and TEM results.
It was also found that the Tripod polishing technique were excellent specimen preparation technique, which could make the cross sections from specified areas of complex, heterogeneous structures. The cross sections from specified areas of trenched Si were prepared by Tripod polishing technique. We were able to prepare the cross sections of trenched Si in the shortest time possible, contain few, if any, artifacts and have a large area available for analysis by Tripod polishing technique.
The cross-sectional TEM specimens of SiGe/Si heterostructure were successfully made by the Tripod polishing technique. And we investigated the artifacts of ion-milled TEM specimens of SiGe/Si heterostructure. TEM results of ion-milled specimens were compared with one of Tripod polished specimens. Ion beam induced intermixing and interface roughening of SiGe/Si superlatice were observed at the ion-milled specimens. It was found that the intermixing and roughening increased as ion beam voltage increased. Precise average thickness of SiGe layer was calculated from TEM results prepared by Tripod polishing.
