Fabrication of Cantilever with Ultrasharp and High-Aspect-Ratio Stylus for Scanning Maxwell-Stress Microscopy

Abstract

A cantilever with an ultrasharp and high-aspect-ratio stylus was made by using a directly bonded silicon-on-insulator (SOI) wafer. The stylus and cantilever were made of 8-µ m-thick Si film and 2-µ m-thick SiO₂ film of SOI with sufficient reproducibility. The cantilever is 100 µ m in length, 20 µ m in width and 1.6 µ m in thickness, and the stylus, 7 µ m in height with an aspect ratio exceeding 2. The apex of the stylus is about 5 nm in radius of curvature. The present cantilever was applied to scanning Maxwell-stress microscopy (SMM), and spatial resolution of about 10 nm was achieved in surface potential images of the metal surface, which was significantly better than that obtained with a commercially available conventional cantilever. The fabrication sequence, mechanical properties of the cantilever and results of SMM measurements are discussed.