Surface Modification by Beams and Plasma Flows of Boron Ions Generated by Vacuum Arc Sources

摘要

A boron ion plasma can be used to form monoisotopic ion beams containing 100% of ${}^{10}B+$ or ${}^{11}B^{+}$ ions. In the present work, we study one of the methods that is used to generate such plasmas and which is based on a vacuum arc discharge with a lanthanum hexaboride cathode. Using an ion source based on a vacuum arc discharge and a magnetic separator, we obtained compositionally uniform ion beams of boron isotopes with atomic masses 10 and 11 a.m.u. We performed a separate implantation of ${}^{10}B^{+}$ and ${}^{11}B^{+}$ ions on silicon and zirconium-niobium alloy surfaces with exposition doses up to $5cdot 10^{15} ext{cm}^{-2}$. The secondary ion mass spectroscopy (SIMS) technique was used to study the implantation profiles of subsurface areas of the materials treated by ion beams. Using identical operation conditions of the vacuum arc as in the case of the ion implantation, the cathode erosion products were deposited on a silicon surface. The scanning electron microscope (SEM) and energy dispersive x-ray spectroscopy (EDS) techniques were employed to analyse the surface microstructure of the cathode and deposited coating as well as their elemental composition.