Focused Ion Beam Milling 2D: Understanding Material Removal at Nanoscale

What is Focused Ion Beam Milling?

Focused ion beam (FIB) milling is a nanoscale material removal technique that uses an ion beam to etch away material from a sample. The process involves directing a focused beam of ions, typically gallium atoms, at the surface of a specimen and removing material layer by layer. This method allows for precise control over the depth and shape of the etched features, making it invaluable in nanotechnology applications such as semiconductor fabrication, microfabrication, and materials science research.

The 2D top-down height-field view provided in this simulation offers a real-time visualization of the milling process, allowing users to observe how different parameters affect the material removal rate and the resulting geometry.

Yamamura Sputter-Yield Law

The Yamamura sputter-yield law is a fundamental principle governing the interaction between the ion beam and the sample surface during FIB milling. This empirical relationship describes how much material is removed (sputtered) from the surface as a function of the incident angle and energy of the ions. The law states that the number of atoms ejected per incident ion, known as the sputter yield, increases with increasing incident angle up to a certain critical angle beyond which it decreases.

This relationship is crucial for understanding and optimizing the milling process, as it directly influences the rate at which material is removed and the shape of the etched features.

Sidewall Taper and Redeposition Effects

During FIB milling, redeposition of sputtered atoms can occur, leading to the formation of ridges on the sidewalls of the etched features. This phenomenon is known as redeposition and can significantly affect the final geometry of the etched structures. The angle-dependent nature of the Yamamura law means that the redeposition rate varies with the incident angle, resulting in different taper angles for different parts of the feature.

Understanding these effects is essential for designing and optimizing FIB milling processes to achieve desired geometries and surface finishes.

Real-World Applications

FIB milling finds extensive use in various nanotechnology applications, including the fabrication of semiconductor devices, microelectromechanical systems (MEMS), and other nanostructured materials. The ability to create precise and complex features at submicron scales makes FIB milling indispensable for research and development in these fields.

In addition, FIB milling is also used for preparing samples for transmission electron microscopy (TEM) by creating thin sections or removing material from specific regions of interest.

Frequently asked questions

Try it live

Everything above runs in your browser — open Focused Ion Beam Milling 2D: Sputter-Yield Height Map and change the parameters while it is running. Nothing is installed, nothing is uploaded, the whole model lives in one tab.