Electric Field Distribution in SOI-Nanoribbon Biosensors with Dielectrophoretic Control

Dielectrophoresis (the phenomenon in which particles in fluid polarize and move in response to spatial variations of an electric field) is an attractive tool for address analyte delivery to a sensor element. One of the key factors that determine the bioparticle movement under dielectrophoretic (DEP) forces is the gradient of the electric field square. In this study, the distribution of the electric field strength square gradient for SOI (silicon-on-insulator) FET (field effect transistor) sensors with DEP control was analyzed to optimize the design of sensor with dielectrophoretic delivery of target particles. The distribution of the electric field strength gradient for sensors was investigated as a function of a) the distance between the sensor element and DEP-electrodes, b) the sensor operation mode, and c) the voltage at DEP electrodes using TCAD modeling. Results showed that for the address delivery of target particles to the sensors, the following conditions are preferable: negative dielectrophoresis, subthreshold sensor mode, and distance to the DEP-electrode less than 1.2 µm.