M. R. Zakaria

Preparation of zinc oxide piezoelectric substrate for saw biosensor device

To develop the SAW device, piezoelectric substrate is one of important factor that improve performance device. The material used such as ITO (Indium Thin Oxide) or LiTaO3 (Lithium Tantalate) extremely affect the cost as well as the preparation methods. To overcome this problem, the material known as ZnO (Zinc Oxide) has been chosen as the thin film layer of piezoelectric in developing the biosensor. These ZnO thin film acts as piezoelectric layer that made contact with the sensing element before the signal convert from a biological signal to an electrical signal by the transducer. Solgel deposition technique was used and zinc acetate as precursor compound and 2-Methoxyethanol as solvent to form the sol-gel. This sol-gel then be spin coat on the SiO2/Si substrate which will later to be anneal with oxygen to make the thin film more dense, thinner and has smoother surface quality and higher resistivity. The surface morphology, electrical and optical characterization of the thin films will be studied using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM), Four Point Probe and UV-Visible Spectropohotometer.

Fabrication of SONOS flash memory device by using engineered tunnel barrier technique

Flash memory is a device that used as a tool to store data electrically without external power supply. The charge-trap such as SONOS structure is the most widely used in flash memory technology fabrication due to the advantages of this device in term of scaling and performance characteristic. Conventional Flash memory with thickness 5nm single oxide shows good performance, but suffer leakage current and data retention. To overcome this problem, a SONOS flash memory was fabricated by using techniques that known as Engineered Tunnel Barrier to replace the conventional single oxide used in conventional flash memory. In this project, the total equivalent thickness oxide for all experiments is set at the 8nm to compare the performances. Thus, it will result in a faster write and erase speed. The analysis results will determine the most preferred structure that improved the programming characteristic.

Electrical properties of titanium dioxide nanoparticle on microelectrode: Gap size effect

TiO2 nanoparticle based interdigitated microelectrode was fabricated by spin-coating and conventional photolithography approaches. Aluminum metal was deposited by thermal evaporator on silicon dioxide substrate. The effect of aluminum microelectrode gap sizes (4, 5 and 6 µm) on the electrical performance was investigated using picoammeter. Extremely small output current values of three different gap sizes were acquired. A characteristic electrical behavior was observed for the studied geometry. The configuration demonstrated a reduction in the output current from 2.28E-10, 1.32E-9 and 2.38E-9 A with increasing gap size.TiO2 nanoparticle based interdigitated microelectrode was fabricated by spin-coating and conventional photolithography approaches. Aluminum metal was deposited by thermal evaporator on silicon dioxide substrate. The effect of aluminum microelectrode gap sizes (4, 5 and 6 µm) on the electrical performance was investigated using picoammeter. Extremely small output current values of three different gap sizes were acquired. A characteristic electrical behavior was observed for the studied geometry. The configuration demonstrated a reduction in the output current from 2.28E-10, 1.32E-9 and 2.38E-9 A with increasing gap size.

Review on Preparation and Properties of High-K Dielectric Material Based on Lanthanum Doped Barium Titanate

Lanthanum doped barium titanate (BaTiO3) were studied for high-K dielectric and exhibit a relaxor ferroelectric properties and it can be prepared by using various method. Relaxor ferroelectric offers a wide temperature and frequency range of application for materials with high dielectric constant for microelectronic application. This paper reviews the preparation methods, the important features, advantages and limitation for the lanthanum doped barium titanate. Thus, the phase purity and mixture selected also been review on the second part of the article. The article concludes with a brief discussion of the methods with good dielectric behavior. The objectives of this paper are to determine the selection of suitable preparation methods and the properties of the high-K dielectric based on pure barium titanate and lanthanum doped barium titanate.

Fabrication and characterization of SAW IDT biosensor for biomolecule detection

Surface Acoustic Wave (SAW) device uses piezoelectric effect to generate acoustic wave on the piezoelectric substrate by using Interdigital Transducers (IDT). Early application was in telecommunication field as filter and resonators. However, due its sensitivity to mass, viscosity and velocity changes on the path between two IDTs, it is used as biosensors. In this project, the focus will be on fabrication and characterization of the IDTs parameter of the SAW device using conventional photolithography and lift-off technique. Finger width, acoustic aperture and number of IDT finger pairs were varied to analyze its effect on the resistance, coupling capacitance, and frequency response. After the lift-off technique, the completed SAW devices were characterized with respect to its parameter for its current-voltage, capacitance-voltage and frequency response. SAW device with more IDT fingers, higher finger width and acoustic aperture produce lower lead resistance and higher capacitance.

Physical properties of hydrothermal growth nanostructure metal titanium dioxide

Growth of titanium dioxide (TiO2) nanowires was studied on the seed layer of TiO2 through hydrothermal growth method. Here, the growth of nanowires TiO2 on Si (100) substrates by using the two steps method. Different seed layers of TiO2 were prepared by using sol-gel method, deposited by spin coating and annealing, followed by the growth of TiO2 nanowires by using the hydrothermal method. Acetic acid was used as a stabilizer to synthesize a TiO2 seed layer. The aim of this study was to understand the role of polycrystalline size on thin film towards the diameter of nanowires grown as a sensing area in Surface Acoustic Wave (SAW) Biosensor. The morphology and microstructure of the thin film seed layer and TiO2 nanowires were characterized using X-Ray diffraction (XRD), scanning electron microscope (SEM), field emission scanning electron microscope (FESEM) and atomic force microscopy (AFM).

Design and simulation study of high frequency response for surface acoustic wave device by using CST software

This paper focuses on the enhancement and improvement of the Surface Acoustic Wave (SAW) device performance. Due to increased demand in the international market for biosensor product, the product must be emphasized in terms of quality. However, within the technological advances, demand for device with low cost, high efficiency and friendly-user preferred. Surface Acoustic Wave (SAW) device with the combination of pair electrode know as Interdigital Transducer (IDT) was fabricated on a piezoelectric substrate. The design of Interdigital Transducer (IDT) parameter is changes in several sizes and values for which it is able to provide greater efficiency in sensing sensitivity by using process simulation with CST STUDIO Suite software. In addition, Interdigital Transducer (IDT) parameters also changed to be created the products with a smaller size and easy to handle where it also reduces the cost of this product. Parameter values of an Interdigital Transducer (IDT) will be changed in the design is the total n...

Simulation based study of poly-silicon nanowire surface for DNA interaction

Simulation is one of the most important approaches in engineering and science, currently most researchers have not waged proper attention that makes it easy to correlate between physical parameters and simulated result. Hence, in this paper, COMSOL Multiphysics simulation is used to design and simulate poly-silicon nanowire surface properties and using electrostatic model, the geometry effect were studied and the different dimension yield different space charge and the partial charge at interactive site were also investigated and the study demonstrate steps wise identification of all critical parameters for (DNA) attachment with surface nanowires.

Effect the functional charge on the conductance poly-silicon nanowire

In this paper investigated into the effect of a bio-interface charge field effect biosensor on the conductance of the nanowire through finite element calculations. The biosensor under thought consisted of a poly-silicon nanowire of radius 100 nm surrounded by a 120 nm oxide layer, and the oxide layer was surrounded by a 160 nm thick functional bio-interface layer. This whole system was immerged in an electrode was 500 nm and every one of the layers was treated as a range medium characterized by the corresponding dielectric constant. First, the distribution of the electrostatic potential in the nanowire due to the surface charge was computed using Poisson equation with Boltzmann statistics. Then, the conductance of the nanowire was affected with interaction with functional layer.

Design and Fabrication of IDT Surface Acoustic Wave Device for Biosensor Application

The Surface Acoustic Wave (SAW) is one of sensor types that can be used in multifunction in the sensing field. Hence, the purpose of this project is to study and investigate the design of SAW device for biosensor application. Several parameters and design has been varied and proposed to investigate the effect to the SAW Biosensor performance. The parameter such as total SAW IDT fingers and Split IDT design has successfully designed using AutoCAD software and fabricated using conventional lithography method. The Aluminum IDT was fabricated on ZnO/Si piezoelectric substrate and show a good result in term of electrical characterization and frequency response. From result, the proposed design with many fingers can increase the center frequency response while the split design control the insertion loss. It shows that these designs are suitable to apply in the SAW biosensor application.