High energy metal ion implantation using a novel, broad-beam, Marx-generator-based ion source “Magis”

Abstract

Ion energy of the beam formed by an ion source is proportional to extractor voltage and ion charge state. Increasing the voltage is difficult and costly for extraction voltage over 100 kV. Here we explore the possibility of increasing the charge states of metal ions to facilitate high-energy, broad beam ion implantation at a moderate voltage level. Strategies to enhance the ion charge state include operating in the regimes of high-current vacuum sparks and short pulses. Using a time-of-flight (TOF) technique we have measured charge states as high as 7 + (73 kA vacuum spark discharge) and 4 + (14 kA short pulse arc discharge), both for copper, with the mean ion charge states about 6.0 and 2.5, respectively. Pulsed discharges can conveniently be driven by a modified Marx generator, allowing operation of “Magis” with a single power supply (at ground potential) for both plasma production and ion extraction.