Influence of biological element permittivity on BE (Back Enhanced) SOI MOSFETs

In this work, the BE SOI MOSFET was studied for the first time as a biological material detector. This device is a planar undoped reconfigurable (i.e., it can act as an n-type or ptype) transistor, with a simple fabrication process. Numerical simulations of the drain current as a function of the front gate voltage were performed based on previous experimental results. The biological material was modeled by changing the permittivity of the dielectric on the gate underlap regions. Due to its unique operation principle, a shift on the threshold voltage was observed depending on the biological element, transistor type and charges in both oxides, front gate and buried ones. In addition, the drain current increased, mainly due to the front interface conduction. The linear behavior of the drain current as a function of the permittivity of the material indicates that the BE SOI MOSFET is a promising alternative as a biosensor.