Laser-induced Implantation Research Articles

Laser-induced implantation of silver particles into poly(vinyl alcohol) films and its application to electronic-circuit fabrication on encapsulated organic electronics

In this study, we propose a new laser-induced implantation based approach for embedding electronic interconnects in this study. Direct implantations of silver particles, vaporized by a pulsed laser from a silver film initially pre-coated on a transparent glass substrate, into poly(vinyl alcohol) (PVA)-encapsulated organic electronic devices as electronic conducting circuits are demonstrated. Two test carriers are the devices of organic thin-film transistors and polymeric light-emitting diodes. Device property characterizations indicate the implanted circuits can work smoothly. The implantation process is driven by the high-energy ejected particles that soften and melt the PVA layer and penetrate into it until their momentums are totally lost. The penetration depth increases with the number of laser pulses and is becoming saturated as the pulse number is getting high. A conducting circuit, with length of 2 μm, can be completely embedded within 3 laser pulses. Due to its flexibility in embedding metals into an encapsulated device, this technique can be used for repairing internal circuit damage. Besides, all steps can be executed in the ambient environment and at room temperature that is suitable for plastic substrate processing.

Fe and Fe+2%Si targets as ion sources via UV laser ablation plasma

In the last years the ion component of a laser-produced plasma has been considered and studied as an object to provide high-density ion sources, which can be applied in many fields such as laser-induced implantation. In this work a KrF laser beam of 108 W/cm2 irradiance was focused onto single-crystalline Fe and single-crystalline Fe with 2% of Si targets and the characteristics of both free expanding laser-produced plasmas were compared. The time-of-flight (TOF) method was applied to determine the ion charge yield at various laser fluences and the ion angular spread. The analyses of TOF spectra showed a synergetic effect of the silicon admixture in target material on the Fe ions production. Besides, this admixture was also responsible of the increasing of the plasma temperature which corresponds in turn to the increasing of the average kinetic energy of the particles as well as of the more collimated ion distribution.

Method of ions acceleration for laser-induced implantation of semiconductor materials

The application of electrostatic fields for the formation of laser-generated ions makes it possible to control the ion stream parameters in broad energy and current density ranges. It also permits to remove the useless ions from the ion stream designed for laser-induced implantation and deposition of layers of semiconductor materials. For acceleration of ions a special electrostatic system has been completed and tested at the Institute of Plasma Physics and Laser Microfusion (IPPLM). A repetitive Nd: glass laser with energy of ∼0.5 J in a 3.5 ns pulse, wavelength of 1.06 μm, repetition rate of up to 10 Hz and intensity on the target of up to 1011 W cm−2, has been recently employed to produce ions emitted from irradiated solid targets. The movable target holder was located inside the cylindrical box connected with a high-voltage source (up to 50 kV). The ions passing through the diaphragm in this box were accelerated in the system of electrodes in the electrostatic field formed in the gap between the box and a grid mounted at the end of the grounded cylindrical electrode. The parameters of the ion streams were measured with the use of several ion collectors and an electrostatic ion energy analyzer (IEA). The Ge ion stream attained energy of up to 30 keV and ion fluency 1011 ions/cm2 for one laser shot. The maximum ion charge state measured with the use of IEA was 3+.

Laser-induced implantation and diffusion of magnesium into silicon

Laser-induced diffusion (“implantation”) of magnesium atoms into silicon was studied experimentally. Neodymium-glass laser irradiation (λ=1.06 µm, τ ∼ 0.4 ms) was found to increase the diffusion coefficient and solubility of magnesium in silicon. Current-voltage and capacity-voltage characteristics, as well as thermostimulated current spectra of 〈Si + Mg〉 crystals, were obtained.

Laser-induced implantation of organic molecules into sub-micrometer regions of polymer surfaces

Organic molecules adhered to the point of a micropipette were transferred onto the surface of a polymer film by pulsed laser light guided through a quartz optical fiber which was inserted into the micropipette. Controlled by a high-resolution piezoelectric driver designed for scanning probe microscopy, the distance between the micropipette point and the polymer surface was kept to a few tens of nm. After laser irradiation, the deposited molecules on the polymer surface were examined with optical transmission, fluorescence, atomic force, and scanning near-field optical microscopy. It was demonstrated that various kinds of organic molecules can be implanted into sub-micrometer regions at the surfaces of polymer films without their decomposition. The hypothetical mechanism of the molecular transfer is discussed in relation to the morphology of crystalline molecules adhered at the micropipette apertures.

Laser-induced implantation of organic molecules into sub-micrometer regions of polymer surfaces

Laser-induced implantation of organic molecules into sub-micrometer regions of polymer surfaces