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We have demonstrated a simple and low-cost method to fabricate poly-silicon microwire by conventional photolithography technique. There are two different steps process flow were involved in the conventional photolithography technique which are employed the positive resist as a mask and aluminium (Al) as hard mask. Low pressure chemical vapour deposition (LPCVD) was used to deposit 50 nm poly-silicon layer on the Si-SiO 2 -Si 3 N 4 layer. Wire mask must be first designed using AutoCAD before patterning onto chrome mask. Initially the 300 nm thick layer of positive resist is coated on the sample. Subsequently, the coated sample were exposed to UV light for 10 seconds and followed by development process. The critical part in this development process is to control the development time and resist profile. There are three types of resist profile problems such as underdevelopment, incomplete development and overdevelopment resist profile. These resist profiles problems can negatively affect in the subsequent etch process. Next process is an etching process. For positive resist as a mask process flow, the developed sample was loaded into SAMCO Inductively Coupled Plasma Reactive Ion Etching (ICP-RIE) 10iP to anisotropic etching of poly-silicon for 7 seconds. Meanwhile, for Al as a hard mask, the developed sample was dipped into Aluminium (Al) etchant for 3 minutes then followed by resist stripping and anisotropic etching of poly-silicon as similar to the resist mask process flow. Finally, the dimensions and etch profiles of < 1um poly-silicon microwire were morphologically characterized using optical microscopy.

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This paper presents the method of preparation and characterization of titanium dioxide (TiO2) thin film before deposition on the channel of field-effect transistor (FET) biosensor devices. The TiO2 is prepared using sol-gel technique and is deposited onto the silicon dioxide (SiO2) surface using spin coater. Three different numbers of coating layers (5, 7, and 9 coating layer) of TiO2 are deposited on three SiO2 layer grown on top of Si substrate for investigation. The samples are baked and annealed before being characterized electrically and morphologically. All these results give a helpful indication for the deposition process of the TiO2 thin film as the FET biosensor device on the silicon-on-insulator (SOI) wafer.

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In this work, we report the geometrical characteristics and the electrical performance of silicon nanowires array for pH level detection. The smallest silicon nanowires structure is 40 nm width and 400 μm length. The Silicon Nanowires Array is tested with pH buffer solutions of pH4, pH7 amd pH10. Direct current (DC) measurement is the most common method of detecting the electrical signals of silicon nanowires sensor. The results show that the IV characteristic is directly proportional and the pH sensitivity calculated from linear relation between the drain-source current vs the pH value was 1.4nA/pH. These results are important for future biosensing experiments and data analysis using Silicon Nanowires Array devices.