A new method for measuring total electron emission yield of insulators

For insulators, the deposited charge on the surface after electron bombardment interferes with the total electron emission yield (TEEY) measurement. The key to measuring the TEEY of insulators is to eliminate the surface deposited charge. Being different from traditional measurement methods, we develop and demonstrate a new method for measuring the TEEY of insulators in a scanning electron microscope by preparing the micro-patterned metal on the surface of the insulators as a conducting channel. The TEEY of the insulators is measured based on the TEEY of the metal part and the metal-insulator periodic structure. By theoretical analysis, we get a criterion for judging whether the deposited charge is eliminated. The result shows that this method is reliable by measuring the TEEY of Si. Then, we obtained the TEEY of SiO₂ by this method with an energy of up to 3000 eV. The measured TEEY characteristics of SiO₂ are consistent with the data from the references. Moreover, the surface charge diffusion distance of the insulators can also be estimated under this measuring condition. We get that the maximum value of the TEEY of SiO₂ is ∼4.2, and the surface charge diffusion distance of SiO₂ is ∼1 µm. In this work, the criterion for judging whether the deposited charge is eliminated is obtained, which has not been proposed in traditional measurement methods.