A New Field-Effect Transistor Based Sensor for Biosensing Applications

This paper presents a new field-effect based sensor for biosensing applications. The sensor composed of a new structure that is based on the junction field effect transistor or JFET that is a well-known electronic transistor. To prepare the JFET for biosensing and solution-based sensing, the p-type JFET is opened from one side (the n-type layer is removed) allowing applying a solution containing bio-chemical substances on top. The opened-gate area consists of silicon with a very thin layer of SiO
2
, which is naturally grown on silicon when exposed to the environment. The p-type channel length between a source and drain is about 100 μm and its thickness is 1.6 μm with 1000 μm wideness. A common source design is introduced containing seven channels that further improves the sensing area (≈ 0.7 mm
²
). To demonstrate the biomolecular sensing capability of the open-gate junction field-e ffect transistor (OG-JFET), dried-DNA is used. Experimental analysis showing a sensitivity of 30 μA/DNA-Concentration (ng/uL) for OG-JFET toward dry DNA.