YIELD MEASUREMENT OF SECONDARY ELECTRONS EMITTED FROM SILICON DIOXIDEFILM IN NEGATIVE-ION BOMBARDMENT

The yield of secondary electrons emitted from insulating materials sub jected to negative-ion bombardment was studied. In general, such measu rements for insulating materials are difficult because surface chargin g due to ion implantation makes the apparent yield unity. We used sili con dioxide (SiO2) him and a small ion current for the yield measureme nts. As a result, charge compensation due to the leakage current minim ized the surface charging and the true yield was obtained. The experim ental results showed that secondary electrons emitted due to negative- ion bombardment consist of electrons due to both kinetic emission and detachment from negative ions. In addition, it was found that the yiel d depends on the ion species. It was concluded that the same tendencie s as those for negative-ion-implanted conductive materials are observe d.