A new method for transmission electron microscope (TEM) specimen preparation using a focused
ion beam (FIB) system that results in a lower rate of gallium (Ga) implantation has been developed. The
method was applied to structural and analytical studies of composite materials such as silicon (Si)-devices and
magneto-optical disk. To protect the specimens against Ga ion irradiation, amorphous tungsten (W) was
deposited on the surface of the specimen prior to FIB milling. The deposition was quite effective in reducing
the Ga implantation rate, and energy-dispersive X-ray (EDX) analysis of these specimens detected 0.3Ð1.5% Ga
incorporated in the thinned area. FIB milling times for these specimens were 1.5Ð2 hr. Although the milling rate was high, all the materials were properly prepared for TEM study,
and clear crystal lattice images were observed on all specimens.