A 3-Dof Mems Motion Stage for Scanning Tunneling Microscopy

Piezoelectric tube scanners used in most conventional scanning tunneling microscopes (STM) are highly resonant mechanisms that require a low-bandwidth controller (< 1 kHz) to minimize ringing, which prohibitively limits scan speed. In addition, hysteresis and creep can dramatically limit positioning precision. We report on a microelectromechanical (MEMS)-based three degree-of-freedom (3-DOF) nanopositioner that can replace piezoelectric tube scanners for STM. The presented MEMS nanopositioner has fundamental resonance frequencies of 8.4 kHz in the Z-axis, 27.0 kHz in the Y-axis, and 79.0 kHz in the X-axis, and has sufficient motion range along all three axes for STM operation. This device will enable high-speed atomic-scale imaging and patterning and can be used for parallel STM operation, with multiple integrated tips on a single chip, to increase imaging throughput.