Characteristics of shunting arc discharge for carbon ion source K. Takaki a, * , S. Mukaigawa a , T. Fujiwara a , M. Kumagai b , K. Yukimura b a Department of Electrical and Electronics Engineering, Iwate University, 4-3-5 Ueda, Morioka, Iwate 020-8551, Japan b Department of Electrical Engineering, Doshisha University, Kyotanabe, Kyoto 610-0321, Japan Abstract The criteria of initial resistance of carbon rod for shunting arc ignition are described in this article. The five different resistances were used. The rods are 40 mm in length and 2 mm in diameter. The carbon rod was set in the vacuum and was initially heated up with a pulsed current supplied by a charged capacitor with a capacitance of 20 lF, followed by a self-ignition. The heating energy is almost independent of the charging voltage of the capacitor. The heating energy increases with decreasing the rod resistance, whereas the energy deposited in the plasma and the utilizing efficiency of the charged energy in the capacitor decreases. Ó 2003 Elsevier Science B.V. All rights reserved. PACS: 51.50.+v; 52.80.Vp; 52.80.Mg; 52.77.Dq; 52.50.Dg Keywords: Ion current; Carbon; Shunting arc; Plasma-based ion implantation (PBII); Ion extraction 1. Introduction The shunting arc, which is newly developed pulsed plasma for metallic and semi-metallic ma- terials including carbon and silicon, is character- ized as self-ignition [1]. The arc is generated using a gentle evaporation by a pulsed current before arcing by the energy release from the identical capacitor bank. As a result, the prepared films include few macroparticles, compared with a conventional metal arc such as a cathodic arc discharge. When a target is immersed in the pulsed shunting arc plasma, the ions are extracted from the ion sheath made by a pulse voltage application to the target. This is a kind of pulsed plasma-based ion implantation (PBII). The shunting arc as a pulsed ion source have been confirmed [2,3]. PBII experiments have been carried out using the shunting arc as a pulsed ion source [4]. Amor- phous carbon films were deposited on a substrate placed near the arc source and a macroparticle- free film was prepared [4]. Although the possibility as the pulsed ion source have been pointed out, fundamental elec- trical characteristics of the carbon shunting arc are not clearly shown. In particular, the rod resistance strongly influences to the ion current characteris- tics. In this article, the dependency of the carbon resistance on the arc current and its related ion current was discussed. These results can be used for optimization in designing the PBII system us- ing the shunting arc as a pulsed ion source. * Corresponding author. Tel./fax: +81-19-621-6941. E-mail address: takaki@iwate-u.ac.jp (K. Takaki). 0168-583X/03/$ - see front matter Ó 2003 Elsevier Science B.V. All rights reserved. doi:10.1016/S0168-583X(03)00851-6 Nuclear Instruments and Methods in Physics Research B 206 (2003) 794–797 www.elsevier.com/locate/nimb