Focused Ion Beam Direct Milling Research Articles

Preparation of MgB2 superconducting microbridges by focused ion beam direct milling

MgB2 superconducting microbridges were prepared by focused ion beam (FIB) direct milling on MgB2 films. The surface topography of the microbridges were observed using SEM and AFM and the superconductivity was measured in this paper. Lots of cracks and holes were found near the milled area. And the superconducting transition temperature was decreased a lot and the bridges prepared were not superconducting due to ion damage after milled with large dose. Through these works, we explored the effect regular of FIB milling and experimental parameters on the performance of microbridges.

High-Tc Josephson junctions fabricated by focused ion beam direct milling

High-Tc Josephson junctions were successfully fabricated by focused ion beam (FIB) direct milling. The characteristics of the junction barrier were carefully controlled by tuning the thickness of the link region. The optimal remaining thickness for the YBCO is about 70–80 nm even though the YBCO thicknesses are different. The temperature-dependence of the critical current provides good evidence of the superconductor–normal–superconductor weak link of the junctions. Although the flux-flow behavior increasingly dominates at lower temperatures, the voltage–current shows resistively shunted junction-like characteristics at temperatures close to Tc. The Shapiro steps of a single junction irradiated with microwaves were measured, revealing strong Josephson effects in ion-damaged junctions. This method will be of great benefit to nanoSQUIDs for the detection of spin systems.

Study of the Plasmon Talbot Effect of Metallic Nanolenses Induced by Linearly Polarized Illumination

The plasmon Talbot effect of metallic nanolenses was studied theoretically and experimentally for the linearly polarized incident beam case. To demonstrate this self-imaging-based focusing property of the metallic nanolenses, a plasmonic nanolens with five periodic concentric through rings on Al film supported on quartz substrate was numerically studied firstly by the use of rigorous finite-difference and time-domain algorithm. To further demonstrate its working performance experimentally, it was fabricated by means of a focused ion beam direct milling technique. A near-field scanning optical microscope (NSOM) was then employed for the optical characterization of its focusing property. The experimental results indicate that the NSOM probing-based results are in agreement with the theoretical calculation results in general.

Experimental Study of Indirect Phase Tuning-Based Plasmonic Structures for Finely Focusing

Three types of indirect phase tuning-based plasmonic structures with subwavelength circular grooves/slits and/or central apertures corrugated on Au film supported by glass substrate: depth modulation, width modulation, and hybrid depth-width modulation, were put forth in this paper. They were investigated experimentally by means of nanofabrication and near-filed scanning optical microscope characterization. The plasmonic structures were fabricated using the technique of focused ion beam direct milling. Our experimental results demonstrated that all of the phase tuning-based structures have focusing functions. Both the width and depth modulation-based structures can realize beam focusing and produce an elongated depth of focus. Moreover, after comparison among these three structures, we found that the width modulation-based structure has the best focusing performance.

DNA-functionalized solid state nanopore for biosensing

The possible use of nanopores for single DNA molecules biosensing has been demonstrated,but much remains to do in order to develop advanced engineered devices with enhancedstability, and controlled geometry and surface properties. Here we present morphologicaland electrical characterization of solid state silicon nitride nanopores fabricated by focusedion beam direct milling and chemically functionalized by probe oligonucleotides, with thefinal aim of developing a versatile tool for biosensing and gene expression profiling.

Experimental investigation of superfocusing of plasmonic lens with chirped circular nanoslits

A plasmonic lens with metallic chirped circular nanoslits corrugated on Au film supported on quartz substrate for the purpose of superfocusing was put forth and fabricated by means of focused ion beam direct milling technique. Topography of the lens was imaged using an atomic force microscope. After that a near-field scanning optical microscope was employed for optical characterization of focusing performance of the lens. Our experimental results verify the focusing performance and further demonstrate that they are in agreement with the theoretical calculation results. Focusing performance is significantly improved in comparison to that of the non-chirped lens. The lenses are possible to be used for the applications of bioimaging, detection, and inspection in submicron scale resolution.

Josephson effects in MgB/sub 2/ metal masked ion damage junctions

Ion beam damage combined with nanoscale focused ion beam direct milling was used to create manufacturable SNS type Josephson junctions in 100 nm thick MgB$_{2}$ with T$_{C}$ of 38 K. The junctions show non-hysteretic current - voltage characteristics between 36 and 4.2 K. Experimental evidence for the dc and ac Josephson effects in MgB$_{2}$ metal masked ion damage junctions are presented. This technique is particularly useful for prototyping devices due to its simplicity and flexibility of fabrication and has a great potential for high-density integration.

Investigation of diffractive optical element fabricated on diamond film by use of focused ion beam direct milling

A novel method of direct transfer of microstructure into diamond films is presented. A diffractive optical element (DOE) with continuous relief and six annuli was directly fabricated on the diamond films by use of focused ion-beam milling (FIBM). The diamond film was coated via hot filament chemical vapor deposition (HFCVD) on a substrate of fused silica. It is shown by the measurement results of Raman spectrum, transmission, and the refractive index of the diamond film before and after the FIBM that little diamond compound is transferred to the graphite during the FIBM, and the influence of the FIBM on the optical properties of the film can be ignored. The surface roughness of the DOE with an R a value of 2.374 nm is derived by use of an atomic force microscope (AFM) in a partial square area of 1×1 μm 2 . By the two-dimensional (2-D) profile and three-dimensional (3-D) topography of the DOE it is shown that the surface is smooth and neat, and the relief depth and annulus width of the DOE are in accordance with the design.

Integration of microdiffractive lens with continuous relief with vertical-cavity surface-emitting lasers using focused ion beam direct milling

A novel one-step integration of bottom-emitting vertical-cavity surface-emitting laser (VCSEL) (operation wavelength of 980 nm) with microdiffractive lens by means of focused ion beam (FIB) technology is described. A diffractive lens with continuous relief, diameter of 140 /spl mu/m, and six annulus was designed and fabricated using FIB direct milling on the backside of VCSEL with GaAs substrate for beam collimation. The divergence angle (half angle) of the VCSEL was reduced from 12/spl deg/ before integration of the VCSEL/diffractive optical elements (DOEs) to 0.6/spl deg/ after FIB integration, allowing for an interconnect length of /spl sim/4 mm. It was proven by device testing that there is little influence upon the VCSEL performance after FIB processing.