A Vertical MOSFET for Charge Sensing in the Convex Corner of Si MicroChannels

摘要

A vertical MOSFET formed in the convex comer of silicon microchannels is presented, which might be useful for detecting charged biomolecules. The cross type microchannels have four MOSFETs and four pairs of source/drain electrodes at each crossing. The non-planar and non-rectangular vertical MOSFET has an effective channel length of 20μm and an effective channel width of 9μm. The measured I-V characteristics of the vertical MOSFET exhibits a typical MOSFET behavior with a threshold voltage of-1.6V. Variation of drain current with time was also measured when the MOSFET was dipped into the thiol DNA solution. The drain current decreased and was saturated after 5 minutes, which we believe might be due to the change of threshold voltage caused by charged biomolecules adsorbed on the Au gate.