Field emission scanning electron microscopes (FE-SEMs) have higher resolution compared to filament SEMs, with magnifications reaching up to 100K times. This poses higher demands on the particle size of the sputter coating instrument, requiring fine particles that do not cover the sample surface and provide improvements in charge elimination and contrast enhancement.

The conventional approach for sample preparation in FE-SEMs is sputter coating with Pt metal. However, the conductivity and electron signal excitation capability of Pt is not as good as Au, especially in 3D powder, porous, and membrane sample scenarios where Pt deposition alone is not sufficient.

Therefore, we have designed a dual target ion sputter coater and developed a layering process: first sputtering a layer of Pt and then a layer of Au. This layered sputter coating mode effectively suppresses the formation of Au islands, while also considering conductivity and particle size, resulting in excellent charge elimination and contrast enhancement for powder and membrane samples.