Spatial Detection of Submicron Particles with Integrated Circuit Charge Sensors

Using a standard MOSIS 0.35 micron Integrated Circuit process, we have built a position sensor for use in all-electrical feedback traps for submicron particles. The device has four transistors in a square, with floating gates that capacitively detect a charged particle in a microfluidic chamber above. The four transistors form the front ends of two independent differential amplifiers that report the x and y position of the particle. Future work towards integration of dielectrophoretic feedback forces for an all-electrical ``Anti-Brownian motion'' trap will be discussed.