INSTRUMENTS

FEI Helios NanoLab 660 Extreme High Resolution Dual Beam FIB

Image of Hilos Dual Beam FIB

University of Hawai‘i’s Helios 660 NanoLab 660 Dual Beam Focused Ion Beam instrument (FIB).

Image of interior of the FIB:

Interior of the FIB: Pole pieces of the electron and ion columns and gas injection needles all aim at the same position on the sample.

Image of graduate student Caroline Caplan at work

Graduate student Caroline Caplan mounts her sample in the FIB.

Click on all images to open a larger version in a new window.

Overview

The FIB, or focused ion beam, is a dual beam instrument.  It combines an electron column and an ion column, mounted at an angle to each other so that both focus on the sample at the same location. This permits highly site-specific analysis, deposition and ion ablation of materials. The electron beam is focused and scanned over the region of interest and typically acts as the “eyes” that allow the operator to image and direct the focused ion beam in “cutting” and “pasting” processes.

“Pasting” is carried out by using either the electron beam or the ion beam to break down gases delivered locally by a small injection needle near the sample surface to leave behind platinum (Pt) or tungsten (W) or carbon (C), depending on the type of gas used. In addition to “pasting”, localized deposition can be used in “growing” nanostructures.

“Cutting” is performed using operator-defined patterns followed by the focused beam of Ga+ ions.

Image of deposition

Deposition of a conductive and mechanically supportive Pt strap and platform underneath a comet dust particle from NASA’s Stardust mission (on reverse side) in preparation for NanoSIMS analysis.

Image of interior of the FIB:

The focused beam of Ga+ ions can be used to mill away material in a highly controlled manner. Here, minerals that would interfere with radioisotope measurements were selectively removed.

An in situ micromanipulator needle can also be inserted to move microscopic objects around. These capabilities translate into an extremely powerful and flexible tool that can be used for nano-engineering and nano-surgery on samples that are sufficiently conductive.

With its heritage in the semiconductor industry, a common application for the FIB is the preparation of electron-transparent samples for the (scanning) transmission electron microscope (S)TEM, referred to as FIB sections. FIB is particularly useful because sections can be removed from precise sites of interest, often discovered by other prior analyses. A protective strap is first deposited over the region of interest. We commonly use Pt for the protective strap, but C or W can also be used. On either side of the protective strap, trenches are milled. Then, the sample is stilled to allow the ion beam to cut the section, still a micron or so thick, nearly free from the bulk sample. The in situ micromanipulator needle is guided over to one corner of the section and “welded” in place by ion-assisted deposition (usually of Pt), and the remaining connection between the section and the bulk sample is milled away to free the section. It is carefully lifted away from the bulk and then moved over to a specially designed FIB grid where it is “welded” to a finger on the grid. The ion beam is used to thin the section down to electron transparency (~100 nm, typically). The FIB section is then ready for examination in the Titan (S)TEM.

Image of section preparation

FIB preparation of an electron-transparent thin section of a meteorite sample.

Image of FIB section is mounted on grid

A FIB section is mounted on the “B” finger of this FIB grid.

Image of FIB grid loaded into the double-tilt holder

FIB grid loaded into the double-tilt holder for Titan (S)TEM analysis.

In general, samples need to be conductive for FIB preparation. Please discuss appropriate sample preparation with staff.

Capabilities and characteristics of the UH Helios 660 dual beam FIB:

[ Top of this page ]