In Situ EELS and TEM Observation of Boron Carbide (B4C){\bf (B}_{{\bf 4}}{\bf C)} During Hydrogen- and Helium-Ion Bombardments

Increasing attention has been paid recently to boron carbide $\rm (B_4C)$ from a viewpoint of plasma-facing materials in a fusion device. This paper reports structural change of $\rm B_4C$ observed in situ by EELS and TEM during hydrogen- and helium-ion bombardments at room temperature. The $\rm B_4C$ became amorphous by the ion bombardments. This amorphization process was presented as a function of the shift of plasmon-loss peak energy and the change of core-loss profiles in addition to electron diffraction patterns. Analysis of core-loss peaks for boron as well as for carbon in $B_4C$ during amorphization process revealed the formation of $\rm sp^2$ type bonding between constituent carbon atoms by the ion bombardments

In Situ EELS and TEM Observation of Al Implanted with Nitrogen Ions

Formation processes of Aluminum nitride (AlN) in Aluminum (Al) implanted with nitrogen were examined by in situ EELS and TEM observations during nitrogen ion implantation in an electron microscope at room temperature and $400\ ^\circ$C. AlN phase was identified both by EDP and EELS after nitrogen ion implantation to$6 \times 10^{20}$$\rm (N^+)/m^2$. The observed peak (20.8 eV) in EELS spectra was identified as the plasmon loss peak of AlN formed in Al. The binding energy of$\rm N_{1s}$in Al was found to shift by about 4 eV to the lower side with increasing nitrogen-ion fluence. Unreacted Al was also found to remain in the AlN films after high fluence implantation both at room temperature and$400\ ^\circ$C