Patterned Ion Implantation Research Articles

Ion-Implanted Laser-Annealed p+ and n+ Regions: A Potential Solution for Industrially Feasible High-Efficiency N-Type Interdigitated Back-Contact Solar Cells

The main challenge for interdigitated back-contact (IBC) solar cells is to reduce the fabrication complexity, which consists of multiple high-temperature processing and patterning steps. Patterned ion implantation has been proposed to simplify the manufacture of IBC solar cells, and the annealing of boron and phosphorus implanted areas is still a problem for the application. In this study, a new method consisting of laser annealing and a subsequent low-temperature oxidation (LA&OX) has been developed to co-anneal boron implanted p + and phosphorus implanted n + regions by a single step. We found that an additional laser annealing before oxidation could improve the electrical properties of boron-implanted p + regions effectively; however, it has almost no effect on the phosphorus-implanted n + regions. An industrially feasible IBC solar cell fabrication technology has been proposed based on the patterned ion implantation and LA&OX processing. The main fabrication steps of the IBC solar cell could be reduced to ten steps, and only one high-temperature oxidation step is required. As-designed IBC cell shows a potential efficiency higher than 23% according to simulations with the experimental parameters.

Optical detection of a single rare-earth ion in a crystal.

Rare-earth-doped laser materials show strong prospects for quantum information storage and processing, as well as for biological imaging, due to their high-Q 4f↔4f optical transitions. However, the inability to optically detect single rare-earth dopants has prevented these materials from reaching their full potential. Here we detect a single photostable Pr3+ ion in yttrium aluminium garnet nanocrystals with high contrast photon antibunching by using optical upconversion of the excited state population of the 4f↔4f optical transition into ultraviolet fluorescence. We also demonstrate on-demand creation of Pr3+ ions in a bulk yttrium aluminium garnet crystal by patterned ion implantation. Finally, we show generation of local nanophotonic structures and cell death due to photochemical effects caused by upconverted ultraviolet fluorescence of praseodymium-doped yttrium aluminium garnet in the surrounding environment. Our study demonstrates versatile use of rare-earth atomic-size ultraviolet emitters for nanoengineering and biotechnological applications.

High efficiency selective emitter cells using patterned ion implantation

Abstract In this paper we present recent advances of the Varian patterned ion implantation selective emitter solar cell process, Solion Blue. Varian's ion implantation system, known as Solion, is currently deployed in manufacturing. This novel doping approach enables 1) simplification of the process flow by eliminating the non-value add steps such as PSG etch and junction isolation common to diffusion-based processes, 2) improved junction quality compared to diffusion processes through precise dopant control, and 3) improved surface passivation using a thermal oxide/silicon nitride ARC. Improvements in emitter quality, through oxide passivation and elimination of the “dead” layer associated with diffusion based processes, has enabled production of > 18.5% efficiency solar cells with simplified processing. The Solion Blue process enables patterned doping using in situ masking, rendering manufacturing of a precise selective emitter with an additional cell efficiency boost. Here we report on the first in a series of optimizations of the ion implanted selective emitter cell process, focusing on assessing the impact of the metallization contact width. These results suggest that, unlike diffusion based selective emitter processes, in which the focus is minimization of the contact width, due to attendant higher surface recombination, the ion implant selective emitter architecture is relatively invariant with contact width, thus enabling a wider contact window. Good surface passivation, precision doping and simplified processing make a compelling case for patterned ion implantation as the preferred doping approach for selective emitter cells and other high efficiency cell architectures, including those that require patterned boron.

Investigation of cell growth on ion beam patterns on GPC surface

We have used implanted silver ions near the surface of Glassy Polymeric Carbon (GPC) to completely inhibit cell attachment and adhesion to GPC. The effect improves the safety and function of the GPC heart valve exposed to the blood stream. The strength, durability and low density make GPC a favored material for in vivo medical applications, including transcutaneous electrodes and replacement heart valves. However, the possible release of endothelial tissue that forms on the smooth surfaces of the GPC heart valve has the potential of creating an embolism. We have shown that L929 endothelial cells avoid silver implanted areas of GPC but attach and strongly adhere to areas close to silver implanted surfaces. Patterned ion implantation permits precise control of tissue growth on GPC and other biocompatible substrates. Cell growth inhibited by silver ion implanted patterns on an otherwise biocompatible substrate may be useful for in vitro studies of the way that cells sense and move away from inhospitable environments.

Patterned Adhesion of Cells

AbstractIt is well known that silver deposition avoids bacterial growth and inhibits the natural process of attachment of connective tissue to biocompatible materials in vivo. We have completed a five year investigation of the precise spatial control of cell growth on glassy polymeric carbon implanted with silver using ion beam techniques, and the persistence of the inhibitory effect on cell growth. Long term inhibition of cell growth on GPC is a desirable improvement on current cardiac implants and other biocompatible materials placed in the blood stream. We have used implanted silver ions near the surface of GPC to completely inhibit cell attachment and adhesion. Cells attach and strongly adhere to areas close to the silver implanted surfaces. Patterned ion implantation permits precise control of tissue growth on GPC and other biocompatible substrates. Cell growth limited to micrometric patterns on a substrate may be useful for in vitro studies of associated biological processes in an otherwise identical environment. The patterned inhibition of cell attachment persists for periods of time significant relative to typical implant lifetimes.

Patterning of Cell Attachment to Biocompatible Glassy Polymeric Carbon by Silver Ion Implantation

ABSTRACTAlthough Glassy Polymeric Carbon (GPC) is ideally suited for implants in the blood stream, tissue that normally forms around the moving parts of a GPC heart valve. There is concern that the tissue lose adhesion and create the condition for embolisms downstream. We have shown that silver ion implantation or argon ion assisted surface deposition of silver inhibits cell growth on GPC, a desirable improvement of current cardiac implants. In vitro biocompatibility tests have been carried out with model cell lines to demonstrate that near surface implantation of silver in GPC can completely inhibit cell attachment on implanted areas while leaving adjacent areas unaffected. Patterned ion implantation permits precise control of tissue growth on medical applications of GPC.

Au Nanoparticles Formed in TiO2 by Patterned Ion Implantation

Au Nanoparticles Formed in TiO2 by Patterned Ion Implantation