Ge post-acceleration from laser-generated plasma

An Nd:YAG laser, 1064 nm wavelength, 9 ns pulse width, 300–900 mJ pulse energy and 1010 W/cm2 intensity is employed to ablate a solid Ge target placed in high vacuum. Ions are produced in vacuum and are emitted mainly along the normal to the target surface. The free ion expansion process occurs in a constant-potential chamber placed at 30 kV positive voltage with respect to the ground. The post-acceleration system permits to extract Ge ions with energy proportional to the charge state. Ion Energy Analyzer (IEA) is employed to measure the energy-to-charge ratio of the Ge ions without and with the use of the post-acceleration system. The ion energy distribution can be measured from time-of-flight measurements. Multi-energetic ion implantation has been performed on Silicon substrates. Ge depth profiles, measured through RBS analysis are in good agreement with IEA spectroscopy measurements.