Sidewall-implanted dual-axis piezoresistive cantilever for AFM data storage readback and tracking

We have developed a novel technique for fabricating high-aspect-ratio sidewall-implanted microstructures, and have used it to fabricate a dual-axis piezoresistive cantilever for atomic force microscope (AFM) data storage. The device allows simultaneous, independent detection of vertical and lateral forces without complex signal-separation circuitry. The vertical force sensor of the cantilever can be used for data readback and load servo, while the lateral force sensor can be used for data groove edge detection and track servo. The dual-axis cantilever consists of a flat, triangular probe with a sharp tip, connected to the support by four parallel high-aspect-ratio ribs. Piezoresistors are fabricated on the horizontal surface of the triangular probe and the vertical sidewalls of the ribs for orthogonal deflection sensing. A special oblique ion implant at approximately 45/spl deg/ to the normal is used to form the piezoresistors. Groove tracking on a spinning disk has been demonstrated using a custom servo controller for load and track servo.