Multiple tip nano probe actuators with integrated JFETs

We report a nano-electromechanical scanning three-probe system with monolithically integrated JFETS. JFETS can be used to pre-amplify differential tunneling currents and atomic forces. The JFET is integrated directly into the probes to reduce parasitics and mismatches and provide enhanced signal transduction and low noise operation. Three probes are co-fabricated, with the center probe being able to move relative to the two fixed probes using electrostatic actuators. The middle probe can be displaced 200nm in both longitudinal and lateral directions in the plane of the wafer, and this motion is sensed through a capacitively coupled JFET preamplifier. The measured transconductance parameter and pinch-off voltage for the JFET were 4.1 nA/V² and -25V.