Piezoresistive cantilever probes for simultaneous nanoscale topography and conductivity imaging

In this paper, we present the design and fabrication of piezoresistive Microwave Impedance Microscopy (MIM) cantilever probes integrated with low impedance, electrically-shielded sharp tips to enable simultaneous topographical and electrical scanning probe microscopy. The fabricated probes show a piezoresistive resolution of 2 nm in 1 Hz to 10 kHz bandwidth, which ensures high quality topographic sensing. The resistance of the center conductor is measured less than 5 Ω and the capacitance between the conductor and shield is 1.7 pF. These parameters are critical for high sensitivity MIM imaging. Piezoresistive topography and MIM images are simultaneously obtained with the fabricated probes at room temperature and cryogenic temperature. These new piezoresistive probes improve MIM capabilities and therefore broaden MIM application in scientific and engineering areas.