A Study on Carbon Capture and Storage and Its Feasibility in Energy-Environment Technologies.

Carbon capture and storage (CCS) has the potential to play an important role in managing global warming in the near future. Herein, we define the entire energy cycle from energy production to utilization considering energy-environment technologies and describe the technical classification and brief technical principles of CCS technology. In addition, we evaluate data from actual scenarios and costs of various indicators established from diverse reports published by reliable institutes on various energy-environment technologies. Finally, the economic feasibility of CCS is determined compared with that of fossil fuel power plants and renewable energy generation in terms of carbon credit for global trading. This techno-economic analysis and systematic review lays the groundwork for comprehensive research toward understanding energy-environment technologies by establishing scenarios in terms of cost and data analysis that can provide an objective approach.

Effect of Contact Plug Deposition Conditions on Junction Leakage and Contact Resistance in Multilevel CMOS Logic Interconnection Device.

Here, we developed the optimal conditions in terms of physical and electrical characteristics of the barrier and tungsten (W) deposition process of a contact module, which is the segment connecting the device and the multi-layer metallization (MLM) metal line in the development of 100 nm-class logic devices. To confirm its applicability to the logic contact of barrier and W films, a contact hole was formed, first to check the bottom coverage and the filling status of each film, then to check the electrical resistance and leakage characteristics to analyze the optimal conditions. At an aspect ratio of 3.89:1, ionized metal plasma (IMP) Ti had a bottom coverage of 40.9% and chemical vapor deposition (CVD) titanium nitride (TiN) of 76.2%, confirming that it was possible to apply the process to 100 nm logic contacts. W filling was confirmed, and a salicide etching rate (using Radio Frequency (RF) etch) of 13-18 Å/s at a 3.53:1 aspect ratio was applied. The etching rate on the thermal oxide plate was 9 Å/s. As the RF etch amount increased from 50-100 Å, the P active resistance increased by 0.5-1 Ω. The resistance also increased as the amount of IMP Ti deposition increased to 300 Å. A measurement of the borderless contact junction leakage current indicated that the current in the P + N well increased by more than an order of magnitude when IMP Ti 250 Å or more was deposited. The contact resistance value was 0.5 Ω. An AC bias improved the IMP Ti deposition rate by 10% in bottom coverage, but there was no significant difference in contact resistance. In the case of applying IMP TiN, the overall contact resistance decreased to 2 Ω compared to CVD TiN, but the distribution characteristics were poor. The best results were obtained under the conditions of RF etch 50 Å, IMP Ti 200 Å, and CVD TiN 2 × 50 Å.

Glucose Sensing Materials Based on Carbon Nanotubes for Electrochemical Sensing.

There is an urgent need for in situ methods for detecting environmental pollution quickly and accurately. With the development of nanotechnology, a huge potential has been created for the design of highly sensitive sensors with low energy consumption and low costs. If a composite material constructed with carbon nanotubes is used as an electrode in contact with a contaminant, this material undergoes an oxidation-reduction reaction with the contaminant that allows the electrode to function as an electrochemical sensor. This study involved the application of multi-walled carbon nanotubes and modified working electrodes constructed with multi-walled carbon nanotube composites (Ag- and ZnO-multi-walled carbon nanotubes) as electrochemical sensors. These electrodes have good response speed and sensitivity at low concentrations, and they are reusable. To lower the price of these sensors, our goal was to maximize their sensitivity by using the low-cost multiwalled carbon nanotubes in conjunction with silver electroless plating of the multi-walled carbon nanotubes and multi-walled carbon nanotube composites.

Characteristics of Metal-Metal Nano-Area Contact Resistance for Less Than 5 nm Technology Node.

Recently, better understanding of nano-area is required for 5 nm or less technology node. In particular, the high contact resistance generated in a nano-area significantly degrades the device performance. In this study, we propose a direct contact resistance measurement method without a test structure by separate processes to improve the nano-area contact resistance. The nano-area contact resistance of Ti-Ti and Cu-Cu decreased from 6.46 MΩ to 1.08 MΩ and from 3.78 MΩ to 1.48 MΩ, respectively, when the metal line and native layer formed on the surface were removed. In addition, it is confirmed that the contact resistance decreased with an increase in bonding strength in the case of nano-area homo-metal contact. However, the contact resistance is affected by the tunneling effect and bond energy according to the distance between the first layers of atoms in the case of nano-area hetero-metal contact.

Process Optimization of Via Plug Multilevel Interconnections in CMOS Logic Devices.

This paper reports on the optimization of the device and wiring in a via structure applied to multilevel metallization (MLM) used in CMOS logic devices. A MLM via can be applied to the Tungsten (W) plug process of the logic device by following the most optimized barrier deposition scheme of RF etching 200 Å IMP Ti (ion metal plasma titanium) 200 Å CVD TiN (titanium nitride deposited by chemical vapor deposition) 2 × 50 Å. The resistivities of the glue layer and barrier, i.e., IMP Ti and CVD TiN, were 73 and 280 µΩ·cm, respectively, and the bottom coverages were 57% and 80%, respectively, at a 3.2:1 aspect ratio (A/R). The specific resistance of the tungsten film was approximately 11.5 µΩ·cm, and it was confirmed that the via filling could be performed smoothly. RF etching and IMP Ti should be at least 200 Å each, and CVD TiN can be performed satisfactorily with the existing 2 × 50 Å process. Tungsten deposition showed no difference in the via resistance with deposition temperature and SiH4 reduction time. When the barrier scheme of RF etching 200 Å IMP Ti 200 ÅCVD TiN 2 × 50 Å was applied, the via resistance was less than 20 Ω, even with a side misalignment of 0.05 µm and line-end misalignment of ~0.1 µm.

Development of a New Electrochemical Atomic Force Microscopy Tool for Obtaining Surface Morphology Through Electrochemical Reaction.

Electrochemical atomic force microscopy is a complex electrochemical analysis method that has been applied in many fields. Electrochemical atomic force microscopy consists of an electrochemical cell, electrochemical analysis system, and atomic force microscopy. To simultaneously analyze the electrochemical system and the atomic force microscopy, an electrochemical cell with a suitable structure is needed. We developed the electrochemical atomic force microscopy analysis system using a self-developed electrochemical cell. To confirm the in-situ analytical ability of the developed electrochemical atomic force microscopy analysis system, we observed the electrochemical corrosion process of copper with respect to changes in pH of a sulfuric acid solution. The operation of the electrochemical atomic force microscopy tool was verified by experiments on the electrochemical corrosion of copper, and the factors affecting the corrosion process were examined. It was confirmed that electrochemical atomic force microscopy can perform electrochemical analysis and atomic force microscopy image analysis at the same time.

Direct Synthesis of Carbon Sheathed Tungsten Oxide Nanoparticles via Self-Assembly Route for High Performance Electrochemical Charge Storage Electrode.

Using a stabilizing agent-assisted co-assembly method, a novel nanocomposite of mesoporous carbon embedded with uniform tungsten oxide nanorods is obtained, which is converted into carbon-sheathed tungsten oxide nanoparticles by delicate calcination and further reduction. Through optimization of tungsten content, it is found that highly crystalline tungsten oxide nanoparticles are uniformly coated with an ultra-thin carbon layer. When applied into electrochemical charge-storage electrodes for supercapacitor and lithium-ion battery, an excellent average capacitance (129 F g−1, above 400 F cm−3), higher rate performance and significantly advanced cycle stability are observed. These improved charge storage properties are attributed to improved electrical conductivity and enhanced structural stability, which is induced by uniform carbon coating on partially reduced tungsten oxide nanoparticles.

Eutectic Bonding Utilizing Radio Frequency Induction Heating for Fabricating Vertical Light-Emitting Diodes.

Vertical light-emitting diodes (VLEDs) have attracted considerable attention owing to their improved thermal, electrical, and optical performance compared to conventional LEDs. To fabricate VLEDs, a bonding technique is required following laser lift-off. Eutectic bonding techniques are preferred owing to their low-heat mechanism and production safety. However, the conventional resistance heating method for eutectic bonding process, the extremely longer process time becomes a problem such as cost rise, wapage. In this study, the thermal efficiency was measured according to the diameter of the coil in order to optimize the eutectic bonding of the RF induction heating method in order to solve this problem. We confirmed that successful eutectic bonding is possible with less than 30 min processing using Sn-Glass. In addition, Au (20 wt%)/Sn (80 wt%) alloy, a mainly used the eutectic bonding interlayer material for VLEDs, can also be used as an interlayer to provide void-free eutectic bonding in less than 30 min.

Hybrid Electrodes of Carbon Nanotube and Reduced Graphene Oxide for Energy Storage Applications.

The choice of electrode materials in lithium ion batteries and supercapacitors is important for the stability, capacity, and cycle life of the device. Despite its low capacity, graphite has often been used as an electrode material due to its inherent stability. Due to an increasing demand for large-capacity energy storage systems, there is also a demand for the development of large-capacity Li ion batteries and supercapacitors. Therefore, carbonaceous materials like graphene and carbon nanotubes (CNTs), which have high stability as well as excellent electrical conductivity and mechanical strength, are receiving attention as new electrode materials. Recently, starting from simply applying graphene and CNTs as electrode materials and progressing to the development of hybrid materials, there have been increasing research efforts in enhancing the performance of Li ion batteries and supercapacitors through the use of carbonaceous materials. This paper will discuss new composite materials and electrode structures that use graphene and CNTs for applications in Li ion batteries and supercapacitors.

Development and applications of 3-dimensional integration nanotechnologies.

Unlike conventional two-dimensional (2D) planar structures, signal or power is supplied through through-silicon via (TSV) in three-dimensional (3D) integration technology to replace wires for binding the chip/wafer. TSVs have becomes an essential technology, as they satisfy Moore's law. This 3D integration technology enables system and sensor functions at a nanoscale via the implementation of a highly integrated nano-semiconductor as well as the fabrication of a single chip with multiple functions. Thus, this technology is considered to be a new area of development for the systemization of the nano-bio area. In this review paper, the basic technology required for such 3D integration is described and methods to measure the bonding strength in order to measure the void occurring during bonding are introduced. Currently, CMOS image sensors and memory chips associated with nanotechnology are being realized on the basis of 3D integration technology. In this paper, we intend to describe the applications of high-performance nano-biosensor technology currently under development and the direction of development of a high performance lab-on-a-chip (LOC).

Applications of scanning probe-atomic force microscopy in nanobioelectronics.

Scanning probe microscopy (SPM) is considered one of the most powerful tools for nanoscale studies that are becoming increasingly important, and SPM has shown rapid development. Atomic force microscopy (AFM), in particular, is the widely used SPM system. SPM, and especially AFM, has been used as a new measuring tool for phenomena that were earlier difficult to prove because of the limitations of earlier systems. In addition SPM allows acquiring nanoscale resolution images of the surface of materials. New applications are constantly being developed for SPM, and it is now used actively in material sciences and biological fields. The most important reason why SPM has attracted attention in the biological field is because it can be used in liquids as well. This allows the study of live cells and various other systems in nanoscale. Recently, there have been many advances in nanoscale studies, such as studies of cell interactions, cell changes according to environmental changes, and development of biosensors. This review is focused on applications in nanodevices, as well as on specific biological applications to discuss the development and opportunities of SPM in the biological field.

Interface modification in solar cell contact electrode using pre-cleaning treatment chemistries.

Promoting and employing photovoltaic power as an alternative energy source, the solar cell industry has made rapid strides. However, improving the efficiency of these solar cells using low-cost fabrication processes is still needed. The interface between the Si surface and the electrode plays a very important role in the process of electrode formation of the solar cell. In this study, the electrode interface underwent four different pre-treatments in order to enhance the efficiency of Si-based solar cells. We analyzed the adhesion properties at the interface between the Si wafer and the electrode and conducted an analysis of the variation in contact resistance between the two contact surfaces. To reduce the cost of the entire experiment, we replaced the existing Ag screen printing-based electrode fabrication method with a low-temperature, low-cost Ni/Cu electroless plating method. The test cells exhibited improved adhesion and therefore improved efficiency as compared to cells treated with the currently used diluted HF.

Reduction process of dislocation and standby leakage current for embedded flash memory using nano-scale integration.

We determined that the use of densification, sacrificial oxidation, gate oxidation and source/drain implantation has the capability to reduce the dislocation. A dislocation-free process is proposed, and its mechanism presented in embedded flash memory. The dislocation decreased when n-type ions were implanted at a low energy level for source and drain. A dry oxidation process using only oxygen without hydrogen and oxidation for logic gates led to the formation of a sacrificial oxide on the rapid thermal oxidation (RTP) methods without densification after gap-filling as reducing dislocation processes. These methods dramatically reduced the standby leakage current.

Effect of particle size of PtRu nanoparticles embedded in WO3 on electrocatalysis.

Size-controlled PtRu nanoparticles embedded in WO3 were prepared by simultaneous multigun sputtering on pure targets of Pt, Ru, and WO3. The mean diameter of the PtRu nanoparticles, as confirmed by high-resolution transmission electron microscopy, can be varied from -2.3 to -3.6 nm by varying the RF power ratio of PtRu and WO3. On the basis of transmission electron diffraction results for the PtRu nanoparticles embedded in WO3, it was confirmed that PtRu exists as an alloy metal phase, whereas the WO3 matrix is present as an amorphous phase. Size-controlled PtRu/WO3 electrodes were found to exhibit unique electronic properties depending on their size, which affected the potential of zero total charge and the methanol oxidation reaction. The mass activity of PtRu/WO3 for methanol oxidation was determined by the interplay of the surface electronic factors at the metal-solution interface; the oxophilicity of the nanoparticles increased with decreasing particle size.

Effect of ashing conditions and optimization of nano process integration in copper/porous low-k nano-interconnects.

We report the optimization of ashing conditions and the process integration of a chemical vapor deposition (CVD) ultra low-k (k = 2.2) organosilicate (OSG) dielectric in a top hard mask damascene structure. The N2/H2 ash showed the lowest resistance-capacitance (RC) product and a dual top hard mask approach for dual damascene processing was built, using 200 nm SiC/50 nm SiO2 as the hard mask. This CVD low-k material had no low-k voiding, unlike other spin-on dielectric (SOD) low-k materials. The presence of the densified layer around the trench during the ashing process could improve the precursor penetration during the CVD barrier metal deposition process.