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In plasma immersion ion implantation (PIII), ions are extracted from the plasma and implanted in a target subjected to high negative voltage pulses. PIII models assume that the uncovering of enough ions at the moving sheath edge establishes a space-charge-limited ion flow that supplies the ion implant current at the target. The present paper reexamines this assumption in one-dimensional planar geometry by relating the implant current at the target to the Child law current through a delay time function that properly accounts for the transit time of the ion through the sheath. Comparison of the total current calculated both at the target and at the leading edge of the sheath demonstrates that the model provides accurate results as long as the ion time scale is shorter than the characteristic times of the applied voltage waveform. Index Terms--Child law, plasma immersion ion implantation (PIII), plasma sheath.

Ion implantation is a well-known technique used in surface treatment of materials. During the 1980s, ion implantation using a sample immersed in an ionized gaseous medium (known as plasma immersion ion implantation) revealed to be an alternative to the conventional ion beam implantation. Development of this nonconventional surface processing using metallic ion species increased significantly when metal vacuum arcs began to be used as ion sources. In this paper, we present the experimental results obtained on Si wafers used as test targets, using metallic arc ion implantation. High-density plasmas (up to [10.sup.19] [m.sup.-3]) made of aluminum vacuum arcs were used for the metallic implantation process. Arc currents of 200-700 A and 16 ms duration were pulsed every 30 s, and samples were biased from 2 kV to 10 kV with 50 [micro]s pulses at 700 Hz, using a hard tube pulser. A straight magnetic filter was used to clean the plasma from macroparticle contaminants, with complete filtering being achieved in samples oriented so that their surfaces were parallel to the plasma stream. This is an interesting alternative to 90[degrees] curved magnetic duct filters usually used for this purpose. High-resolution X-ray diffraction analysis shows that aluminum was successfully implanted. Index Terms--Ion implantation, metal-arc, plasma, surface material treatment.

Blumlein pulse generators have been used with great success for high voltage pulse generation. They are capable of producing pulses in the nanosecond or microsecond ranges depending on the transmission line length and on the topology used. The main problem with this type of generators relates with the presence of stray fines that degrade the overall gain of the device. In this paper, we are proposing a design method of a 150 kV/300 A coaxial Biumiein pulser with pulse duration of 1 [micro]s in which the parasitic effects are minimized by winding the transmission fines on coil formers. Also we have developed a model that estimates the pulser voltage gain from just two parameters: the number of stages and the impedance ratio of the transmission fine characteristic impedance and the parasitic secondary mode impedance. The model can be applied to other types of Blumlein generators with different geometries such as those made of strip transmission fines. Index Terms--Blumlein generator, coaxial fine, high voltage pulser, transmission line.

This paper describes an experiment and modeling in plasma immersion ion implantation using a high-voltage pulsed power system. This consists of a high-voltage pulse generator that uses a hard tube switch. The reason for using this type of circuit category in the Plasma Immersion Ion Implantation (PIII) facility rather than a previously used pulse-forming network (PFN) circuit configuration is stated. The experimental results of the application of this device to a glow discharge PIII are also discussed. In order to assess these results, a simple electrical model describes the plasma as a resistive load in parallel with a capacitance taking into account the pulse rise-time distortion caused by a long connecting coaxial cable. Plasma parameters for PIII processing, such as ion average implantation current and plasma sheath thickness, are calculated from the experimental settings. Index Terms--Hard tube pulser, high-voltage pulse generator, ion implantation, plasma immersion ion implantation.

A chain of cascading LC sections consisting of series nonlinear inductors and parallel linear capacitors can be used to generate oscillating pulses. When a rectangular pulse is injected into the input of such a nonlinear inductive line (NLIL), the pulse undergoes modulation and exits at the output with oscillations in the waveform. This paper describes the implementation of high-voltage NLILs using commercial-off-the-shelf components. A pulser comprising of a storage capacitor and a fast semiconductor switch is used to provide the input pulse with approximate rectangular pulse shape. The design of the NLIL, which is a type of nonlinear lumped element transmission line (NLETL), is based on a NLETL circuit model developed earlier in-house. The nonlinear inductors made of ferrites are modeled using a simplified form of the Landau–Lifshitz–Gilbert (LLG) equation. A simple novel approach is proposed to determine the characteristic parameters in the LLG equation. Simulation results from the NLETL model are compared to the experimental results, and analyses on the voltage modulation and frequency content of the output pulses are performed. The use of crosslink capacitors in the line to modify the dispersive characteristics to enhance the performance is also investigated. With the results, the conditions and trends for producing oscillating pulses in NLILs are discussed. [ABSTRACT FROM AUTHOR]