Middle-East Journal of Scientific Research 18 (9): 1281-1285, 2013 ISSN 1990-9233 © IDOSI Publications, 2013 DOI: 10.5829/idosi.mejsr.2013.18.9.12085 Corresponding Author: M.R. Zakaria, School of Microelectronic Engineering, Uni MAP. 1281 Design and Fabrication of IDT SAW by Using Conventional Lithography Technique M.R. Zakaria, U. Hashim, R. Mat Ayub and Tijjani Adam 1 1,2 2 2 School of Microelectronic Engineering, Uni MAP 1 Institute of Nano Electronic Engineering (INEE) 2 Abstract: The Surface Acoustic Wave (SAW) devices, using interdigital electrodes, play a key role in today’s telecommunication systems and are widelyused as electronic filters, resonators, delay lines, convolvers or wireless identification systems (ID tags). The geometry of the device play greater role in determing its optimum performance. Hence.The purpose of this study is to investigate the behavior of fingers various for surface acoustic waveinterdigital transduction which could be subsequently used in biosensor application. Two groups of miniature SAW biosensor IDT fingers are successfully designed and fabricated using conventional lithography method. The combination of ZnO as a piezoelectric substrate and aluminium as an IDT show a good result in term of electrical characterization and frequency response. From the result, shows that increasing number of SAW IDT has higher 2.40 MHz center frequency and hence can improve the sensitivity. It shows that these designs are suitable to apply in the SAW biosensor application. Key words: IDT SAW design SAW device Biosensor INTRODUCTION generate and detecting the SAW. IDT structure was For decade, many types of Biosensor have been used photolithography steps. It is typically designed as developed.These sensors had been developed using a thin-film layer is placed on the surface of the different methods and technique, mostly based on piezoelectric substrate [4]. When the signal voltage is radiochemical, enzymatic, fluorescence, electrochemical, applied, an IDT will generate acoustic waves in a optical and acoustic wave [1]. However, the result of some piezoelectric substrate. Acoustic waves generated vary biosensor had been reported that there is a lack using depending on the applied voltage signal and the the sensor in term of high complexity, separate labelling deformation of the piezoelectric substrate. The process, equipment to simulate the transducer and thus wavelength of the wave excited by the IDT is equal higher cost to conduct analysis [2]. In Biosensor device, to the periodicity of the IDT pattern. The interdigital it's very important to have a sensor with high sensitivity transducer (IDT) can be developed in different structure and have good accuracy detection. When comparing to according to the different characteristics that needed [5]. other method, sensor based acoustic wave had many This paper focused on designing the IDT for more advantages such as high sensitivity, reusable, achievinghigher center frequency. versatile, reliable and easy designed for responding to various measurement. It’s also reported the acoustic Theoretical Background: In SAW device, the center wave proven powerful and sensitive devices for the frequency is the most important specification. When detection of Biomolecule interaction [3]. center frequency is high, the sensitivity also will be The surface Acoustic Wave (SAW) is generated from improved [6]. In order to design a SAW device with a device that know as interdigital transducer (IDT) higher center frequency, parameter such as number of that's been fabricated on a piezoelectric substrate. In IDT finger (N), finger width and spacing between developing SAW sensors, IDT is an important part of IDT,aperture length (W), and wave length ( ) are very generating SAW. It functions by converting electric important. Center frequency can be obtainedby using energy into mechanical energy and vice versa in order to Equation 1.1. developed using a common fabrication method, which is