An In-House Approach for Fabrication of Poly-Silicon Nanobiosensor Using Conventional Photolithography and Etching Method

In this work, we demonstrated a method to fabricate and characterize poly-silicon nanowires for biosensing application using conventional photolithography and etching process. Nanowires Mask must be first designed using AutoCAD, before patterning onto chrome mask. Chrome mask was used for better photo masking and to transfer structure onto poly-silicon layer. The poly-silicon nanowires process flow were developed which includes all the fabrication process such as growth, deposition, lithography and etching process. In order to prove the effectiveness of the fabricated devices as a biologically sensor (Biosensor), the poly-silicon nanowires is modified chemically to allow the integration with biological element. The drain (Id) was found to increase after the DNA immobilization and hybridization. These results demonstrate that the in-house fabricated poly-silison nanobiosensor is capable as a platform for label-free biosensing. The morphological characterizations were carried out using a Scanning Electron Microscope (SEM) and Atomic Force Microscope (AFM). Besides that, the electrical measurement of the poly-silicon biosensor were carried out using a KEITHLEY 6487 picoampmeter/voltage source.

Fabrication of Aluminum Interdigitated Electrode for Biosensor Application Using Conventional Lithography

A simple technique for the fabrication of interdigitated electrode (IDEs) using conventional lithography was presented. A top-down simple lithography approach was used to fabricate a set of Interdigitated electrodes were patterned with aluminum metal. Silicon dioxide serves to isolate the electrode from the substrate. A chrome mask was proposed to complete this work. In this work, the proposed method was experimentally demonstrated by fabricating the IDEs structure 4-5μm, approximately. The dimensions of structure were determined by using scanning electron microscopy (SEM). It is a simple, easy-to-use and cost effective method and does not require complicated micro-lithography process for fabricating desired microelectrode in reproducible approach.

Characterization of Micro-Gap Electrodes Initial Pattern on Resist by Employing High Sensitive and Selective Chrome Mask

The detection of most serious diseases at early stages is one of the challenging tasks for researchers of nanotechnology. Therefore the current research article is one of the attempts to fabricate highly sensitive and selective micro-gap electrodes at initial level; such micro-gap electrodes will be used in future for inserting biomolecule in between the gap spacing. To transfer the micro-gap design pattern to sample wafer accurately and preciously, micro-gap was initially designed by using AutoCAD software and the design was finally transferred to high sensitive and selective chrome mask. The article demonstrates experimentally an initial strategy for fabrication of micro-gap electrodes at resisting using conventional photolithography technique coupled with the wet etching process. The structure morphology was characterized using high power and scanning electron microscope namely (HPM and SEM).

Micro-Gap Electrodes Fabrication by Low Cost Conventional Photo Lithography Technique and Surface Characterization by Nanoprofiler

The fabrication of sensitive and selective nanodevices is one of the important challenges for future detection of low concentration single bio molecule. The current research article is one of the attempts to achieve such sensitive and selective micro-gap electrodes by simple, low cost controllable process. Therefore high sensitive chrome mask was designed for micro-gap design transformation to wafer samples. At first the positive photoresist namely PR-1 2000A was spin coated on the samples wafer at different rotation speed. Then by implementation of low cost conventional photolithography technique an initial structure of micro-gap was patterned on wafer sample. Finally by using surface Nanoprofiler the thickness of resist coated wafer samples were investigated. The obtained results show that the thickness of the resist is directly related with spin coating speed of spin coater.

Mask Design Platform for Zinc Oxide Nanowire Growth

This paper mainly represent the simple and effective method to design the chrome mask for patterning theplatformfor zinc oxide nanowire growth. The most essential aspect that need to be considered in designing the chrome mask is the critical dimension of the mask. Hence, the mask is design by usingAutoCADsoftware to design the desired size and length dimension of the mask. Fabrication and development of zinc oxide consist of a series of major steps. The silicon sample will be initially cleaned, followed by zinc oxide deposition and the zinc oxide nanowire will be growth in vertical direction by using VLS (Vapor-Liquid-Solid) mechanism. The nanowire will be patterned by using the chrome mask which design the platform of the nanowire formation. The initial design of the chrome mask is measured and compared to the fabricated chrome mask to detect the efficiency and the accuracy of the pattern transfer process. Our aim is to develop a comprehensive platform for prominent zinc oxide nanowire growth leading to novel and efficient functional of zinc oxide nanowire devices.

Chrome Mask Design for Microfluidic Fabrication

This paper presents a simple and effective method to design chrome mask for microfludic fabrication. Microfluidic fabrication involves 9 major step and mainly depends on the master mold template formation by SU-8 photoresists using conventional photolithography process The chrome mask was design using AutoCAD software. Essentially, mask is a crucial element in a microfluidic fabrication in which resolution requirements and precise alignment are vital, each mask needs to be precisely aligned with original alignment mark. Otherwise, it cant successfully transfer the original pattern to the wafer surface causing microchannel formation failure. Thus, the initial design is compared with the fabricated chrome mask to achieved a better result during device fabrication.

Nanoelectrode Chrome Photomask Design and Specification for Biosensor Fabrication

This paper explains the most crucial part of any microchip fabrication, which is the mask design for photolithography process. The design is initially sketched roughly to meet the design specification and later on designed using AutoCAD software. Therefore, to meet the required criteria, the overall width and length of the device is optimized at 12mm and 20.21mm respectively. Optimization of the size is done based on the chip behavior as a disposable chip and adding an economical value when it is commercialized. The nanoelectrode mask layout comprises of four sets of design which are single gaps for size reduction, single gaps for size expansion, multiple gaps for size reduction and multiple gaps for size expansion. While, the second chrome mask is fabricated for gold contact padding with two types of design sets, one is for single gaps and another is for multiple gaps. Both mask designs were sent for chrome mask fabrication for future use in biosensor fabrication.

Parametric Study and Thickness Evaluation of Photoresist Development for the Formation of Microgap Electrodes Using Surface Nanoprofiler

A compact nanolaboratory on single chip is one of the challenging tasks for future reproductively of sensitive and selective lab-on-chip. This paper reports a simple and controllable technique for patterning microgap structures on (PR-1 2000A) positive photoresist. For the pattern transformation conventional lithography technique was used integrated with precise resolution mask namely chrome mask. This technique provides an especially simple method for the formation of micro features sizes of gaps onto the photoresist. The thickness of developed microgap structures on photoresist directly relates with the coating speed of spin coater.