Direct implantation of Ge ions produced by high-energy low-intensity laser pulses into SiO2 films prepared on Si substrates

Abstract

Due to the development and growing demands for implantation techniques, the laser plasma as a source of multiply charged ions has been investigated. With focusing the laser beam on the solid target it is possible to produce higher current densities of ions than with other currently available ion sources. Kinetic energy and the charge state of ions depend on the properties of the irradiated target material and the parameters of the laser radiation used. Selection of proper laser beam characteristics is very important for efficiency of the ion implantation technology. Several experiments on the implantation of different kinds of laser-produced ions have been performed at the Institute of Physics ASCR and at the PALS Research Center, ASCR in Prague. During these experiments 0.4 ns iodine laser pulses of energies up to 750 J at a wavelength of 1315 nm or up to 250 J at a wavelength of 438 nm have been used for generation of ions. The significant part of these experiments concerned the characterization and optimization of laser-produced Ge ion fluxes as well as the analysis of the direct implantation of these ions into SiO2 films prepared on the surface of a Si single crystal. In this paper we present the results, analysis and conclusions of these experiments which include ion collector and ion analyser measurements and the bulk profiles of Ge ion implantation with maximum depth of ∼450 nm.