Ion implantation from post-acceleration laser-generated plasma

A Nd:YAG laser, 1064 nm wavelength, 9 ns pulse width, 300-900 mJ pulse energy and 10 10 W/cm 2 intensity is employed to ablate solid ta rgets (Ti, Ge and Cu) in high vacuum. The laser-generated plasma was characterized through ion energy and optical spectroscopy. Equivalent plasma temperature, density and ion energy distribution were measured properly. The plasma is generated inside an extraction chamber which can be connected, together the target holder, to a high posi tive bias. The ion emission from the target plasma expands in vacuum adiabatically. The extraction chamber permits the ion extraction through a 6 mm diameter axial noose. 0-30 kV voltage bias can be applied between the extraction noose and the final grounded collimator placed at 10 cm distance. The ion ejected from the laser- generated plasma and submitted to the post-acceleration, just after the noose, have a high directionality, energy and cu rrent. Ion energy increases proportionally to the ion charge state and to the positive bias voltage. 30 keV monoenergetic protons and 30-180 keV multi-energetic Ti ions were detected with high current. Ion collector, ion energy analyzer and ion implantation technique on different substrates (Si, Al, C) are employed to analyze the post-accelerated ions . Evaluation of the implanted dose per laser shoot, ion range versus bias voltage, time-of-fli ght ion detection and RBS surface analysis of implanted substrates are presented and discussed.