Advanced Materials Research Vol. 576

Abstract: Porous silicon nanostructures (PSiN) are nanoporous materials which consist of uniform network of interconnected pore. The structure of PSiN is depending on etching parameters, including current density, HF electrolyte concentration, substrate doping type and level. In this work, the results of a structural p-type and n-type of porous silicon nanostructures were investigated by Field Emission Scanning Electron Microscopy (FESEM) and Atomic Force Microscopy (AFM) is reported. Samples were prepared by photo-electrochemical anodization of p- and n-type crystalline silicon in HF electrolyte at different etching time. The surface morphology of PSiN was studied by FESEM with same magnification shown n-type surface form crack faster than p-type of PSiN. While the topography and roughness of PSiN was characterize by AFM. From topography shown the different etching time for both type PSiN produce different porosity and roughness respectively. There is good agreement between p- and n-type have different in terms of surface characteristic.

Abstract: This article reports on the electrical properties of porous silicon nanostructures (PSiNs) in term of its surface topography. In this study, the PsiNs samples were prepared by using different current density during the electrochemical etching of p-type silicon wafer. PSiNs has been investigated its electrical properties and resistances for different surface topography of PSiNs via current-voltage (I-V) measurement system (Keithley 2400) while its physical structural properties was investigated by using atomic force microscopy (AFM-XE100).

Abstract: Process variation is inevitable for any production line regardless of the industry. The trend for smaller, lighter yet multifunctional devices has created high expectation for the semiconductor manufacturer to produce more robust and highly reliable devices. One way to achieve this is by assessing the variance performance of the assembly production. In this study, the mechanical properties of copper alloy C194 used as the lead frame for particular IC device have been investigated. Samples from control and defect groups been subjected to hardness (Rockwell test) and tensile (Instron test) while the optical microscopy used to verify the microstructure. The result shows that the hardness and tensile of the defect group is relatively lower than the control group while the elongation of the defect group is almost 10% higher. This finding is very useful to be shared with the process owner so that in-depth investigation on the lead frame material consistency or the temperature range optimization can be carried out to prevent such variations that contribute to the inconsistence wire bond yield performance.

Abstract: This paper presents the estimation of kerf width in micro wire electrical discharge machining (micro WEDM) in terms of machining parameters of capacitance and gap voltage. An empirical model is developed by the analysis of variance (ANOVA) of experimental data. Using a wire electrode of 70 µm diameter, a minimum kerf width is found to be 92 µm for the micro WEDM parameters of 0.01 µF capacitance and 90.25 V gap voltage. Around 30% increament of the kerf is found to be high. The analysis also revealed that the capacitance is more influential parameter than gap voltage on kerf width produced by micro WEDM. As the gap voltage determines the breakdown distance and affects the wire vibration, the wire vibration factor is to be considered in the analysis and in formulation of model in future study.

Abstract: Silicon Carbide (SiC) is a type of ceramic that belongs to the class of hard and brittle material. Machining of ceramic materials can result in surface alterations including rough surface, cracks, subsurface damage and residual stresses. Efficient milling of high performance ceramic involves the selection of appropriate operating parameters to maximize the material removal rate (MRR) while maintaining the low surface finish and limiting surface damage. SiC being a ceramic material, its machining poses a real problem due to its low fracture toughness, making it very sensitive to crack. The paper discusses milling of silicon carbide using diamond coated end mill under different machining conditions in order to determine the surface roughness parameter, Rt after the machining processes and to establish a relationship between the machining parameters and response variables. Based on the surface roughness carried out the lowest Rt obtained is 0.46 µm.

Abstract: The primary applications of silicon carbide SiC-based materials, which include include micro-structures, optoelectronic devices, high temperature electronics, radiation hard electronics and high power/high frequency devices to name a few have necessitated the need for machining SiC. The paper presents the outcome of milling of silicon carbide using diamond coated end mill under different machining conditions in order to determine the surface roughness parameter after the machining processes. Relationship between the machining parameters and response variables has been established and a mathematical model has been predicted, the minimum roughness value, Rz being 0.19 µm.

Abstract: High hardness, chemical stability, attractive high temperature wear resistance, low density and strength at elevated temperature are the advantages of ceramics over other materials. These properties have made a number of components made of hard and brittle materials, typically represented by advanced ceramics gained applications in industrial sectors over the past two decades. Nevertheless the benefits due to the salient features of ceramic materials go along with some difficulties with machining in general because of their high values of hardness and very low fracture toughness as compared to other metallic materials and alloys. This paper presents an experiemntal study on identifying the diamond grit size and grinding condition that produced low surface roughness value, Ra and less micro-fractures on ground silicon carbide work-piece material.

Abstract: Silicon thin film was successfully deposited on glass substrate using Radio frequency (RF) magnetron sputtering. The effect of deposition pressure on the physical and structural properties of thin films on the glass substrate was studied. The film thickness and deposition rate decreased with decreasing deposition pressure. Field emission scanning electron microscopy (FESEM) shows as the deposition pressure increased, the surface morphology transform from concise structured to not closely pack on the surface. Raman spectroscopy result showed that the peak was around 508 cm-1, showing that the thin film is nanocrystalline instead of polycrystalline silicon.

Abstract: Micro turning is a process by which micro components can be produced. This paper deals with the CNC micro turning of Inconel 600 alloy with titanium nitride insert tool. Full factorial experiments were conducted to obtain tool Flank wear and Surface roughness (Ra) for different cutting conditions. Using the measured data, Grey Relational Analysis is used to predict the optimal parameter conditions for controlled tool flank wear and better surface finish.

Abstract: Wire Electrical Discharge Machining is one of the important non-traditional machining processes, which is used for machining difficult to machine materials and intricate profiles. In this present study, machining is done using Wire-Cut EDM and experimentation is planned according to Taguchi’s design of experiments [2]. Each experiment has been performed under different cutting conditions of gap voltage, pulse ON time, and pulse OFF time and Wire feed. Inconel 800 was selected as a work material and Brass wire of 0.25mm diameter as the tool to conduct the experiments. From experimental results, the surface roughness and Kerf Width was determined for each machining performance criteria. Grey Relational Analysis [1] is used for optimization of Surface Roughness and Kerf width.