The application of focused ion beam (FIB) technology in microfabrication has become increasingly popular. Its use in microfabrication has advantages over contemporary photolithography or other micromachining technologies, such as the ability to process without masks and being accommodating for a variety of materials and geometries. With the surface modification of the LED/air interface, like microlens array, the light emitting at large angle can be extracted because the incident angle at the interface will be less than the critical angle without total internal reflection. A microlens feature has been fabricated on GaN LED top surface (p-GaN layer) and back side (sapphire substrate) by scanning a focused Ga ion beam. The lens shape can be modulated by using computer-controlled beam direct writing and dwell time during milling process. We have used this technique even to create a sophisticated lens surface of Fresnel microlens array which can't be created with the conventional etching methods. In addition, the resistivity of p-GaN layer is highly sensitive to the process-induced damages during surface texturing, it is difficult to apply dry etching to p-GaN layer. Our method of using gas-assisted focused ion beam etching (GAFIBE) can enhance the etching rate by the assistance of chemical reaction with minimized ion dose density to provide nearly damage-free etching by varying the beam current, pixel dwell time and refresh time. Our study emphasis on direct milling and maskless techniques which can distinguish the FIB technology from the contemporary photolithography process and provide a vital alternative to it.

On InGaAs/AlInAs heterostructures we made nanowires which were made by focus ion beam (FIB) and the width of nanowires making by FIB were 40nm¡B70nm¡B100nm and 200nm respectively. we studied electronic characterization of nanowires using Shubnikov-de Haas(SdH).In our research,by using SdH method there are no signal in our sample which processed by FIB,then we changed to process technology in our sample.For example: Increase thickness of the protection layer,size of change channel,etc.

In recent years, there has been an increasing interest in the study of hydrophobic surfaces. Hydrophobic surfaces have been used in multiple applications in microfluidic devices due to their properties of self-cleaning, and also in deicing products. Conventionally, hydrophobic surfaces were created by laser cutting, self-assembly and other chemical processing methods. However, in most of these methods, hydrophobicity of the surface cannot be maintained for an extended time or restricted to limited set of materials. A low-cost, high-throughput method to generate highly hydrophobic anisotropic surface has been developed in this thesis which uses Computer Numerical Control (CNC) machining employing diamond tools whose tips have been micro-structured using Focused Ion Beam (FIB) built tips. The versatility of this method has been demonstrated by machining both metal and polymeric materials. Significant anisotropic wetting has been observed on the machined surface with the anisotropic contact angle can reach up to 71.6 degree and highly-hydrophobic property with contact angle of 163.1degree on 6061 Aluminum Alloy and 155.7 degree on PMMA surface. / Thesis / Master of Science in Mechanical Engineering (MSME)

Orientadores: Jacobus Willibrordus Swart, Stanislav Moshkalev / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-13T05:10:33Z (GMT). No. of bitstreams: 1 Silva_MarceloMacchida_M.pdf: 6148337 bytes, checksum: d4ca724ac84a5417bdd4995685227913 (MD5) Previous issue date: 2007 / Resumo: A nanotecnologia e uma área nova e promissora que englobam muitas disciplinas de ciência e engenharia. Seu rápido crescimento nas ultimas duas décadas é devido ao crescimento simultâneo na fabricação e caracterização de materiais em escala nanométrica. O objetivo deste trabalho é desenvolver uma técnica de processo híbrido para a fabricação de micro e nanocontatos assim como sua caracterização elétrica. Esse processo híbrido combina a fotolitografia seguida da técnica de lift-off e a deposição de platina por FIB. Para determinar a resistividade da platina depositada por FIB (Focuded Ion Beam), foram fabricas estruturas quadradas variando sua espessura de 5 nm - 100 nm e sua área 150 µm 150 µm e 20 µm x 20 µm. Resistores com comprimento de 30 µm variando sua área de secção (50 nm x 50 nm - 1 µm x 1 µm) foram fabricados a fim de uma melhor na caracterização do processo de deposição do filme de Pt assim como sua caracterização elétrica. As medidas elétricas foram realizadas na estação Keythley 4200 SCS, onde foi utilizado o método de quatro pontas nas estruturas quadradas para a caracterização da resistividade. Nos resistores utilizamos a configuração de dois terminais para a caracterização de resistência dos nanocontatos. / Abstract: Nanoscale science and technology is a young and burgeoning field that encompasses nearly every discipline of science and engineering, the rapid growth of the field in the past decades has been enable by the sustained advances in the fabrication and characterization of materials. This work presents the hybrid process for fabrication of micro and nanocontacts, this process include the lift - off technique and platinum deposited by FIB. For measurements, two types of test structures were fabricated: (i) 150 x 150 µm and 20 x 20 µm squares with thickness of 5, 10, 30 and 100 nm, and (ii) 30 µm long resistors with variable cross - section (50 nm x 50 nm to 1 µm x 1 µm). The Pt film resistivity has been measured by a four points probe method. / Mestrado / Eletrônica, Microeletrônica e Optoeletrônica / Mestre em Engenharia Elétrica

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The glancing angle deposition (GLAD) technique is now used by over one hundred research groups, each requiring a fundamental understanding of and new techniques for modulating the properties of GLAD in order to optimize their results. In this thesis, the structural characteristics of nanostructured columnar films were therefore investigated and quantified using gas adsorption porosimetry, focused ion beam tomography, optical methods, scanning electron microscopy (SEM) image analysis. Questions such as ``What is their surface area?'', ``How porous are they?'', ``How do the films evolve as they grow?'', and ``Can the structural characteristics be manipulated?'' were answered. Surface areas, determined from krypton gas adsorption, were found to be high, making GLAD promising for applications requiring large and rough surface interfaces. Specifically, peak specific surface areas of 700 +/- 150 m^2g^{-1}, 325 +/- 40 m^2g^{-1}, 50 +/- 6 m^2g^{-1} were measured for silica (SiO_2), titania (TiO_2) and indium tin oxide (ITO), respectively. Broad pore distributions, with peaks in the low mesoporous regime of 2 nm to 5 nm, were also determined. The internal surface area may also be up to three times as high as that of the externally exposed surface. As well, despite the fact that GLAD column broaden as they grow, the surface area increases linearly with film thickness. Focused ion beam milling, with concurrent SEM imaging, was then employed to investigate and reconstruct the three-dimensional structure of GLAD films in the tens of nanometers regime not measurable by krypton gas adsorption porosimetry. The measured growth scaling trends agreed with previous findings, but were determined using only one sample, instead of multiple samples of increasing thickness. Mean column diameters, center-to-center spacings, void spacings, and column densities were found to scale with thickness as w = (9.4 +/- 3.0) t^{0.35 +/- 0.09} nm, c = (24.8 +/- 5.2) t^{0.31 +/- 0.08} nm, v = (15.2 +/- 3.8) t^{0.25 +/- 0.06} nm, and d = (3400 +/- 2500) t^{-0.65 +/- 0.15} columns um^{-2}, respectively. Finally, spatially graded nanostructures were demonstrated by extending the GLAD technique to include macroscopic shadowing. Optically transparent, graded thickness and pitch helical films were fabricated with polarization selectivity over a spatial range of 30 mm, concurrent with 70 nm spectral tunability. These structures will be useful for tunable frequency photonic devices. / Micro-Electrical-Mechanical Systems (MEMS) and Nanosystems

The fabrication characteristic of etching and deposition of focused ion beam (FIB) on the submicron structure of silica and quartz glass was investigated. FIB has several advantages such as high sensitivity, high material removal rate, and direct fabrication in some selected areas without the use of etching mask, etc. In this study, silicon and quartz glass materials etched by FIB were used for fast fabrication of 3-D submicron structures to investigate the differences between the samples before and after fabrication. The expansion effect of silicon with sputtered platinum on surface is compared with Pyrex glass with sputtered chromium on surface. The result shows the side wall of structure in the center wouldn¡¦t be vertical after etching and trimming on the quartz glass and the silicon substrate. Trenches with different depth and width on the surface of silicon were etched by FIB and measured by Atomic Force Microscope. Lines with different interval were deposited by FIB on the surface of quartz glass and were measured by Atomic Force Microscope.

Micro/Nano-Electro-Mechanical Systems (MEMS/NEMS) applications for in vivo cell studies open a wide range of new applications in medicine, biology, and biochemistry. This has lead to develop devices for local drug delivery, microneedles for DNA injection, and micronozzles for cell holding among others.The work presented in this manuscript is framed within two projects: MINAHE and MINAHE II. The main goal of MINAHE was the development of technologies suitable for fabrication of micro/nano tools. Tools fabricated under MINAHE has found application in gold surface patterning and sub-picoliter dosage driven by an Atomic Force Microscope. MINAHE II employed these micro/nano tools on cellular applications.Following the current integration trend in microelectronics, two different integrative technologies have been developed and will be discussed here. The first technology presented is based on Microsystems technology combined with Focused Ion Beam (FIB) nanomilling. The fabricated device has been fitted to an Atomic Force Microscopic (AFM) for gold surface patterning. Experience developed in the first generation of micro/nano dispensers promoted a number of upgrades to produce a new generation of dispensers with emphasis for application in the Life Sciences. Technological processes were developed from component definition to back-end fabrication. Microchannel were defined on- substrate with micronozzles at the tip. The whole ensemble had AFM chip dimensions. This design favoured the use of microchannels as micro/nanodispensors and could effectively be used as surface functionalization tools. Once the components were identified, fabrication processes took place at Instituto de Microelectrónica de Barcelona, INM-CNM (CSIC) Clean Room (100-10000) facilities. First generation of micro/nanodispensers has sucessfully formed Self Assambled Monolayers (SAM). Experience developed in the first generation micro/nanodispensers promoted a number of upgrades to produce a Second generation of dispensers with an emphasis for applications in the Life Sciences. Transparent new devices were defined with specific shapes for cell manipulation. Anisotropic etching was replaced by Dry Reactive Ion Etching (DRIE) for improved process control. Packaging was improved with anodic bonding between silicon and glass chips and individual chip yield was increased by manual cleaving instead of wafer dicing. Transparent wall micro/nanodispensers would be designed due to biological application. To avoid lysis (cellular damage) or broken nozzles, some nozzles were designed sharply, in order to pierce wall and membrane surrounding live cells. FIB nanomachined render this type of nozzle. A crucial advantage in MEMS technology is versatility and monolithic integration. MEMS versatility can yield different devices although using the same technological process. We took advantage of this feature and manufactured microelectrodes, microfilters and micromixers as well. As a conclusion, it is worth emphasizing that research in this work range from micro/nanotechnologies to chemistry and biology. The first generation fabricated technology successfully formed SAM over gold surfaces. The second generation pierced walls and membranes in live cell. These devices present quite some advantages compared to conventional glass capillary. The proposed technology allows extreme definition of sizes and shapes in order not to damage cells. Microelectrodes fabricated will be tested inside a neuron cell to record electrical measurements. Work to develop this new application is still in progress.

The fabrication characteristic of focused ion beam (FIB) for fused quartz was investigated. With the progress of nanotechnology, new technologies and devices are invented constantly. In nanofabrication, FIB has several advantages such as high material removal rate, high resolving power and direct fabrication in some selected areas without etching mask. Therefore, it had been studied in detail to fabricate nano-structures by FIB. In this study, we found out the effect of nano-machining by adjusting the parameters of FIB system such as: beam current, overlap, and dwell time. The fabricated features together with their surface morphology and profile were investigated by scanning electron microscope (SEM) and atomic force microscope (AFM). Results show that when beam current was smaller, overlap was 50% and dwell time was 10£gs could get best performance by FIB.

We have observed a large spin-splitting in device made of AlxGa1-xN/GaN quantum wires. Based on this observation, we proposed a new spintronic application, the spin-hall quantum-ring interferometer, by the spin-Hall effect, Rashba and Dresselhaus effects. This device we use the ICP Etch System to etch the contact pattern, and then use the Multi-Target Sputter to deposit the protecting layer, and then use the E-Beam Evaporator to make the contact. Finally, using the Focus Ion Beam, we fabricate the quantum-ring and gate successfully. This thesis is focused on discussing the design of the fabrication and try to solve the problem in order to be able to detect the signal of the quantum-ring interferometer at low temperature and high magnetic condition.