Enhanced Model for Scanning Tunneling Microscope Tip Geometry Measured with Field Ion Microscopy

Published

March 10, 2004

Author(s)

P V. Rao, Carsten P. Jensen, Richard M. Silver

Abstract

Estimating the shape and size of a scanning tunneling microscope (STM) tip before scanning is often necessary for the correct interpretation of the STM data. This is particularly essential when using the STM as a metrology tool. It is common among researchers to idealize the tip shape as conical, spherical, or parabolic. By using a field ion microscope (FIM), the tip shape and size can be measured directly on an atomic scale. Based on FIM measurements, it has been realized that simple idealizations of the tip shape are not satisfactory in many cases, particularly for sharp tips. In the present work, we have developed an enhanced model of the shape of a STM tip measured with FIM using Lame's curves. The proposed model, which assumes an axisymmetric tip shape, is validated with comparisons between the theoretical simulations of FIM images and experimental FIM images from tips made of tungsten (110). For tips smaller than a limiting size, applications of the model may no longer be valid.

Citation

Journal of Vacuum Science and Technology B

Volume

22

Issue

2

Pub Type

Journals

Keywords

characterize SPM tips, detailed shape of the tip, field ion microscopy (FIM), scanning probe microscope, tip character

Citation

Rao, P. , Jensen, C. and Silver, R. (2004), Enhanced Model for Scanning Tunneling Microscope Tip Geometry Measured with Field Ion Microscopy, Journal of Vacuum Science and Technology B (Accessed April 25, 2024)