抄録
Secondary electron (SE) images of the surface of a thin carbon microgrid (CM) firmly covering a copper plate substrate were investigated using a deceleration optics system SEM. The CM was prepared by carbonization of a formvar microgrid used for the transmission electron microscope, 40 nm in thickness, at 700 °C in a N2 atmosphere, placed on a smooth flat copper plate substrate. The CM is regarded to be composed of a low conductivity material. The estimated thickness was 40 nm. Observation was conducted with the electron probe accelerated at voltages in the range 0.1-30.0 kV. Characteristic SE images of the CM-covered copper plate substrate as a function of accelerating voltage V0, i.e. probe electron energy E0, were obtained. The clearest images of the CM surface were observed with E0 in the range 0.1-1.0 keV. The variation of the SE image versus E0 was interpreted with the aid of a Monte Carlo electron trajectory simulation for the CM-covered copper plate substrate.
