Design and Simulation of InP and Silicon Nanowires With Different Channel Characteristic as Biosensors to Improve Output Sensitivity

Abstract

This research contains a good comparison among technologies of SiNW-FET/InPNW-FET depending on the size of channel and dopants in channel for biosensing application based on the width and dopants for two types of silicon and InP materials in the nanowire channel. A device numerical modelling tool, Silvaco ATLAS is used in step one to design three p-type SiNW-FET/InPNW-FET biosensors with a channel width of 40­­­ nm, 60 nm and 70 nm for these two types of materials and in step two to design three p-type SiNW-FET/InPNW-FET biosensors with different dopants of 0.1×1014 cm-3, 1×1014 cm-3 and 10×1014 cm-3 for these two types of materials. Their sensing process is depended on the alteration in charge density that causes changing in the electric field at the surface of the SiNW-FET/InPNW-FET. The resistivity of the device is changed when a negatively charged biomolecules species has a chemical reaction with the external surface of a P-type SiNW-FET/InPNW-FET. To investigate the effect of different channel width and dopants on the performance of the SiNW-FET/InPNW-FET biosensor, several negatively interface charge densities, QF (-0.1×1012 cm-2, -0.5×1012 cm-2, and -1×1012 cm-2) are introduced on the surface of the SiNW-FET/InPNW-FET channel to represent as the actual target analytics (DNA) captured by the bioreceptor of the biosensor. Based on the results, these negatively QF attract the hole carriers below the surface of p-type nanowire causes to collect carriers in the channel, and make an increase in the device output ID. Increase of the applied negative charge density has allowed for more ID to flow across the channel between drain and source region. The changes of ID with the applied QF are utilized to determine the sensitivities for all designed biosensor with different channel width and channel dopants. The minimum nanowire width of 40 nm with the minimum nanowire dopants of 0.1×1014 cm-3 for the high sensitivity silicon state of 3.6 μA/cm-2 compared to the indium phosphide state of 2.8 μA/cm-2. So the best performance for detecting the desired analyte in the silicon state with the lowest width and dopant to be seen.