69 Abstract At the PALS laboratories of Prague (Czech republic), IPPLM of Warsaw (Poland) and INFN- LNS of Catania (Italy) experimental tests have been carried out to implant Ge ions in Si substrates through laser-generated Ge-plasma. Si substrates were placed in a vacuum chamber at different dis- tances and angles from the Ge-target. Online measurements of ion energy were o- btained by time of flight (TOF) techniques using an ion energy analyzer IEA which permitted to draw information about the charge states and the Ge io- n’s energies. Off-line measurements were obtained by Rutherford backscattering spectrometry (RBS) of 2.25 MeV He 2+ beam at CEDAD Laboratory of Brindisi (Italy). RBS analysis permitted to evaluate the Ge implant in Si substrate in terms of concen- tration and ion depth profile. Moreover, the RBS spectra have given information about plasma ion yield and energy as a function of the laser intensity, distance from the target and angular position. Results indicated that ion implants show high Ge ion energy and typical deep profiles only for substrates placed very near to the normal to the tar- get surface and for high laser pulse intensity, while for low laser intensities and/or for substrates far from the normal to the target there is only a Ge deposition effect. INTRODUCTION Lasers at different intensities are used to ge- nerate hot plasmas by irradiating solid targets in vacuum. The plasma expands in vacuum at super- sonic velocity along the normal to the target surface accelerating electrons, ions and neutrals. The high charge state and energetic ions follow a Boltzmann energy distribution [1]. Interesting information can be obtained by time-of-flight TOF measurements of ions, which indicate the presence of an high electrical field de- veloped inside the plasma and responsible of the high ion acceleration along the normal direction to the target surface. The ion energy and charge state can be mea- sured by using an IEA (Ion Energy Analyzer) that gives information of TOF measurements of ions emitted from the plasma [2]. To confirm the measu- rements of ion energy, the 2.0 Mev alpha RBS a- nalysis (Rutherford Backscattering Spectrometry) has been employed to investigate on the depth pro- files of the implanted species [3]. Plasmas produced by pulsed energetic lasers find many applications in several scientific fields. In this work laser ablation of Ge was investigated, particularly for the implantation of Ge in silicon substrates. Si-Ge alloy is often used in microelec- tronic and optical fields because shows peculiar properties. The Ge implantation, in fact, may pro- duce changes in the optical (transmission, absor- ption), in the electrical (conductibility specially for polymers, hole and electron’s mobility, resistivity), in the mechanical (hardness, wetting, friction, ela- stic constant ) and in the thermal surface properties (thermal conductibility) depending on the used im- planted dose [4]. EXPERIMENTAL SECTION Laser ablation of Ge targets have been produ- ced at LNS of Catania (Italy) and IPPLM of War- saw (Poland) both using a Nd:YAg laser in the first harmonic at 1064 nm with 9 ns pulse duration and 900 mJ maximum pulse energy, 10 Hz repeti- tion rate. The laser spot was 1 mm 2 in diameter and the incidence angle was 33°. The intensity of pulse was approximately around 10 12 W/cm 2 . The abla- tion occurred in a vacuum chamber at 10 -6 mbar and the substrates were placed at 9 cm and at an angle between 0° and 50°. Laser ablation of Ge targets have been produ- ced at PALS laboratory of Prague (Czech Republic) by using an iodine laser emitting a fundamental wavelength of 1315 nm. The duration of the laser L. Giuffrida (1),(2) , L. Torrisi (1),(2) , F. Caridi (1),(3) and A. Borrielli (1),(3) (1) Dip.to di Fisica, Università di Messina, Ctr. Papardo 31, 98166 S. Agata, Messina, Italy (2) INFN-LNS of Catania, V. S. Sofia 64, 95125 Catania, Italy (3) INFN-Sez. CT, Gr. Coll. Messina, Ctr. Papardo 31, 98166 S. Agata, Messina, Italy Ge ION IMPLANT FROM ENERGETIC LASER- GENERATED PLASMA