Optimization on Conventional Photolithography Process of 0.98 μm Gap Design for Micro Gap Biosensor Application

.Pattern design transfer is the most crucial step in fabrication. Even a small mistake in fabrication can result in device damage or poor performance. To ensure the device performs perfectly, exact design and dimension pattern should be perfectly transferred onto wafer substrate. In this paper, optimization of conventional photolithography process of 0.98μm gap design for micro gap biosensor application is presented. The micro gap pattern on chrome mask is used and the effect of coating profile, UV light, and Post Exposure Bake (PEB) process are investigated. The conventional photolithography process (using a micro gap mask) starts after the silicon oxide, polysilicon and aluminium have been deposited on top of the substrate. Each set of experiment conducted by pairing the element investigated coating profile, UV light, and PEB, with the normal specification of photolithography process. It was observed that 0.98μm gap size can be achieved by choosing suitable process parameters i.e. thickness of coating profile, time and temperature used for UV light and PEB.</jats:p

Impact of nanogap thickness on dielectric-modulated field-effect transistor biosensor performance for uncharged biomolecules detection

Uncharged biomolecules sensing performance of dielectric-modulated field-effect transistor (DMFET) biosensor at various nanogap thickness via semiconductor device simulation tool was assessed in this work. The device structures with 10 nm-, 15 nm-, and 20 nm-thick nanogap were constructed for this investigation. Each device structure was applied with dielectric constant ranging from 2 to 7 at the nanogap representing the presence of various biomolecules. These device structures were electrically simulated by supplying gate voltage from 0 V to 2 V and biased with drain voltage of 0.05 V for linear region of operation. Based on the extracted drain current, the reduction of nanogap thickness increase capacitance at the nanogap region. In additional, increase in nanogap's dielectric constant causing an increase of its capacitance, and translated into higher output drain current. Sensitivity calculation and analysis shows DMFET biosensor with 10 nm-thick nanogap demonstrated the highest sensitivity with 6.896 μA/dec, which possibly permit enhanced sensing of uncharged biomolecule