Arc discharge ion source for europium and other refractory metals implantation

Abstract

The best method for the impurity doping to the host material is the ion implantation. Due to high melting point of the rare earth standard metal ion sources are useless. One of the solution is to use chemical compounds of rare earths characterized by low melting point. In this paper we describe the novel design of the ion source suitable for refractory metal (e.g., rare earths) ion implantation. The dependencies of Eu(+) current on cathode and arc currents as well as on hydrogen flow are presented. Europium (III) chloride as the source of the europium atoms was used. Europium ions were produced during collisions of evaporated and decomposed EuCl(3) molecules with fast electrons. The typical current of the europium ion beam extracted from the ion source was 25 microA for the extraction voltage of 25 kV. The ion source works without maintenance breaks for approximately 50 h, which enables high dose implantation. The presented ion source needs neither advanced high power supplies nor high vacuum regime.