The Journey BeginsDesign of Experiment and APT

Preparation for Success1ST PRE-MEETING CONGRESS ON ATOM PROBE TOMOGRAPHY (APT)

Richard L. MartensCentral Analytical Facility

The University of Alabama

M&M 2016 JULY 24TH

Alternate Titles• DOE&APT, Yup. You Know Me• Trial by Fire• DAMN My Ambition• What the Hell was I Thinking?

https://www.isixsigma.com/tools-templates/design-of-experiments-doe/design-experiments-%E2%90%93-primer/

Design of experiments (DOE) is a systematic method to determine the relationship between factors affecting a process and the output of that process. In other words, it is used to find cause-and-effect relationships. This information is needed to manage process inputs in order to optimize the output

Material (Sample)

Specimen Preparation &

Instrument Parameters

Data/No Data

Microstructure & Environment

Better Check Yourself

• “Who” is my material? – Evaporation fields– Mechanical Properties?

• What are the questions? – Composition? Microstructure? Clustering?

• WHEN? How much time do I plan to invest?• WHERE is my ROI?• Why APT?

UA-CAF Research Instrumentation

FEI Quanta 200 3D Dual-beam

FIB

JEOL 7000 FEG SEMOxford Aztec EDS,

EBSD, WDS E-beam litho

Chemical mapping

EBSD camera

Electron probe

2 theta

(110)(100)

Specimen

(111)OIM

Site-specific sample prep

Bruker GADDS XRD

FEI TECNAI F20 TEM

2 nm2 nm

High-res imaging

Local Electrode Atom Probe

atom map

Rapid phase ID

Chemical bonding

1-, 2- and 3-D characterization capability from the atomic scale to hundreds of microns – >106

orders of magnitude in imaging capability!

KRATOS AXIS 165 XPS

TESCAN LYRA XMU FIB-FESEM

atom probe preparation

TEM preparation

Qualitative phase ID

Precession Electron Diffraction of Atom Probe Specimens

JEOL 8600 EPMA

WDS –Qualitative Analysis

CAMECA LEAP 5000

EDAX TEAM EBSD, EDS

Bruker EDS & GATAN CL

Four Main Components of an APT Specimen

SAMPLESPECIMEN

“Wedge” or “Lift-Out”

PLATINUM (Pt-weld, Pt-dep) SHARPENING

(Tip Radius/Geometry)

Environmental Factors:Specimen Preparation

• Ion beam damage and “re-deposition”• Quality of platinum weld• Tip shape/geometry

– Apex– Post

• DOCUMENT!!! Record images• Be careful about e-beam contamination

Platinum Deposition (Weld, Brazing)

Sharpening

Edges or No Edges?

Document!

Measure & Record!

The GOOD

The BAD

The UGLY

Show Me the Data

Specimen “Yield” Rate

LEAP Instrument Parameters

• Laser vs. Voltage mode• Temperature• Pulse Rate• Pulse Fraction• Laser Energy

Less Stress, More Resolution, Please

“Improving Data Quality in APT” D.J. Larson, et al, M&M 2014 proc

Specimen vs. Electrode

POST MORTEM ANALYSIS

50 nm

100 nm

100 nm

PED Orientation Image

TEMLEAP raw data

With FeCr density isosurface

TEM BF image before

PED scanning

TEM BF image after

PED scanning

Correlative Analysis

Xuyang ZhouUA-Graduate student

Greg Thompson Group

CORRELATE & COLLABORATE

“Influence of Fe(Cr) miscibility on thin film grain size and stress” Xuynag Zhou, et al, Thin Solid Films 2016

FOLLOW THE SOP’s

• “Specimens will either run or not run”– Mike Miller

• “When specimens work, it is good. When they do not work, things are very difficult”– Kazuhiro Hono

Summary