A Novel Dual-Axial AFM Cantilever With Independent Piezoresistive Sensors for Simultaneous Detection of Lateral and Vertical Forces

Abstract

This paper describes a novel dual-axial AFM cantilever with independent piezoresistive sensors for simultaneous detection of lateral and vertical forces. The cantilever consists of a flat, triangular probe with a vertical direction of compliance, implanted with a piezoresistive layer to form a vertical deflection sensor. This probe is connected to the base by tall, narrow “ribs” that give the structure lateral compliance. Embedded on the side-walls of some of the ribs are a second set of piezoresistors that form a lateral deflection sensor. A special ion implant at approximately 45 degrees to the vertical is used to create the piezoresistive sensors and electrical connections. Both the vertical and the lateral deflection sensors exhibit measured piezoresistive sensitivities ΔR/R on the order of 5 × 10−7 per Å. The cantilever was successfully used to obtain AFM images of a known sample, yielding correlated z-signal and x-signal images of the sample topography.