Non-conventional high voltage pulsers for advanced plasma immersion ion implantation

The treatment of surfaces by plasma immersion ion implantation requires pulsed power modulators to provide negative high voltage pulses. In general, the most commonly used modulators consist of either a pulse forming network (PFN) or a hard tube (HT) pulser. For high implant current above 100 A the former configuration is preferred because of the limited maximum current of the hard tube switch (generally a tetrode) used in the latter one. However, for a PFN generator operating with high voltage pulses it is necessary to use a pulse transformer, which is expensive and responsible for limiting the pulse rise time. In this paper we discuss this conventional technology available and propose a new circuit topology approach for applications with high current and voltage in excess of 100 kV (such as PIII process in polymers) which is cheaper and less complex to build. Also results of the PIII processing obtained in various materials (as silicon and stainless steel samples) using both types of conventional modulators are highlighted