SEM/FIB: TFS Hydra PFIB

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Hydra Plasma Focused Ion Beam

Overview

The Hydra is a high energy, high current Plasma Focused Ion Beam Scanning Electron Microscope (PFIB-SEM) located in Room 007 of the Spilker Engineering & Applied Sciences Building. The PFIB features a gas ion source for high ion beam currents and the ability to generate beams from four ion species. The Hydra enables large volume milling, provides an alternative for gallium-sensitive materials, and has two attachments for elemental analysis: Energy Dispersive X-ray Spectroscopy (EDS) and Secondary Ion Mass Spectrometry (FIB-SIMS).

Additional Capabilities:

Up to 2500nA of Xe⁺ beam current @ 30keV to remove large volumes of material.
Milling rate 20-50x greater than Ga⁺ to allow patterns in excess of 50 µm x 50 µm to be completed within minutes rather than hours or days.
Choice of xenon, argon, oxygen or nitrogen ion species to optimize milling performance and minimize FIB artifacts.
Gallium-free for sensitive materials such as III-V semiconductors or aluminum containing materials.
Energy Dispersive X-ray Spectroscopy (EDS) is paired with Secondary Ion Mass Spectrometry (FIB-SIMS) for semi-quantitative elemental and isotope analysis with surface-sensitive detection of light elements, including lithium.

Principles of Operation

Inductively Coupled Plasma (ICP) source

The Hydra PFIB is equipped with an Inductively Coupled Plasma (ICP) source for generation of positive ions of xenon, argon, oxygen and nitrogen.

Ion selection

Advantages of a Xe⁺ PFIB

Maximum ion beam current for Xe⁺ at 30keV is 2500 nA exceeds the 65 nA available with a Gallium Liquid Metal Ion Source (LMIS).
Xe¹³¹ has a higher atomic weight and size than Ga⁶⁹ which further increases the atoms sputtered per primary ion (sputter yield) for many materials and reduces the depth of ion implantation.
"Gallium-free" as Ga⁺ doping by implantation can change the physical and electronic properties of a sample. For III-V semiconductors or aluminum containing materials, a PFIB can avoid some interactions that cause embrittlement and structural changes.

Advantages of an Ar⁺ PFIB

A further increase in milling speed can be obtained for some samples with argon if the same sample quality can be obtained with higher currents. Spin Milling Application Note

Reactive Ion Sources (O⁺ and N⁺)

Switching to O⁺ or N⁺ ions can minimize FIB artifacts which can be especially pronounced in carbon systems like diamond, polymers, and biological samples.

Elemental and Isotope Analysis

FIB-SIMS Secondary Ion Mass Spectrometry

Secondary ions contain information about the composition and structure of a sample. The FIB-SIMS attracts ions from the sample to a mass analyzer optimized for qualitative imaging.

Adding FIB-SIMS to the Hydra PFIB allows:

High current to explore composition and chemistry of large volumes (> 100 µm deep).
Excavation by ion milling of regions of interest for elemental and isotope analyses.
- Air sensitive materials can be encapsulated for loading and uncovered by ion milling for analysis.
Light element detection and isotope analysis that is not provided by EDS.
Flexibility of ion source gas (Xe, Ar, O, N) and energy (1-30 keV) allows for optimization of selectivity and resolution.

Comparison of Selected SIMS Techniques

Advanced Techniques and Capabilities

Charge neutralizer for patterning insulating samples.
Energy Dispersive Spectroscopy (EDS) for elemental analysis.
Maps 3 for SEM with Correlative Workflow for image acquisition over large areas.
Secondary Ion Mass Spectrometry (FIB-SIMS) for chemical imaging.
Auto Slice & View 5 for sequential milling and viewing images for 3D reconstruction.
EasyLift Nanomanipulator.
Large area serial PFIB imaging for biological samples.

Contact Information

Paul Wallace
Hydra Staff
Message: (650) 785-3336

Spilker 007 (Hydra)
Spilker Engineering & Applied Sciences Building
348 Via Pueblo
Stanford, CA 94305

Getting Started

Complete the process to become a lab member of SNSF and follow the instructions to activate a Badger account.
Complete the Hydra Consultation Request Form.
Subscribe to the hydra-users@lists.stanford.edu for details and updates.