Scanning Probe with Tuning Fork Sensor, Microfabricated Silicon Cantilever and Conductive Tip for Microscopy at Cryogenic Temperature

Abstract

A quartz tuning-fork (TF)-based scanning probe is presented for local electrical transport measurements on quantum devices below the liquid 4He temperature. The TF is utilized to drive and sense the mechanical oscillation of an attached, microfabricated cantilever featuring a conductive tip made of platinum silicide. The microfabricated structure allows the application of an external voltage to the tip, while the cantilever is electrically grounded. The probe was characterized at room temperature, 70 K, and 2 K. It was found that spatial sensitivity decreased with temperature. Imaging a gold surface at 2 K was successfully performed. A number of probes can be batch-fabricated, thus shortening the lead time for conducting experiments in cryogenic scanning force microscopy. © 2006 The Japan Society of Applied Physics.