REELS
Reflection Electron Energy Loss Spectroscopy
1
JAMP-9510F
Field Emission Auger Microprobe
Lithium Analysis Using Reflection EELS
A Joint Project with The National Institute of Advanced Industrial Science and Technology
On April 1, 2016, JEOL Ltd. (Gon’emon Kurihara, President) and the National Institute of Advanced
Industrial Science and Technology, a national research and development organization (Ryoji
Nakahachi, Director) officially announced a new joint project; Lithium Analysis using reflection EELS
(Electron Energy Loss Spectroscopy).
Reflection EELS is an analytical technique to measure kinetic energy change of electrons resulting
from inelastic scattering when a beam of electrons is projected at a few keV onto the sample
surface. Detailed analysis of the energy loss peaks of electrons provides chemical and structural
information on the sample surface (approximately 10 nm deep). The objective of the joint project
is to develop a scanning electron microscope designed for lithium analysis, which supports high
energy resolution spectrometry using a hemispherical detector, as well as analytical techniques
applicable to evaluation of lithium cell materials.
At the initial stage, JEOL will contribute to the joint project in the fields of microscopy and
metrology utilizing expertise in preliminary sample preparation and Auger spectrometry for lithium
analysis.
3
Field Emission Auger Microprobe
TFEG-SEM
For High Resolution
Imaging
High Current, High
Stability Field Emission
Electron Gun
Ar Ion Gun
For Surface Processing
(Cleaning & Depth Profiling)
and Charge Neutralization
Hemispherical Auger Electron
Detector (HSA)
For Surface Analysis
E/T Secondary
Electron Detector
5-Axis Mechanically
Eucentric Specimen Stage
(X, Y, Z, Tilt, Rotate)
to maintain a clean surface
Ultra High Vacuum
Specimen Chamber
(5×10-8 Pa or better)
to maintain a clean surface
θ
φ
HSA
(Electron Analyzer)
Sample
Some incident or back
scattered electrons can excite
electron shells of atoms at
the sample surface. Those
electrons are observed in an
Auger spectrum as energy
loss peaks. We can analyze
the energy positions of loss
peaks to investigate the
atomic chemical state of
atoms much like TEM EELS
but with much less sample
prep
Secondary Electron peak
Loss peaks
Auger elecron peaks
Secondary Electron
0
Auger can provide an EELS spectra of the top surface
8000
Counts (arb. unit)
7000
6000
[Reference Data]
TEM EELS spectrum of SiO2
[REELSspectrum (SiO2)]
1kV, 60nA, M1(Ep=10eV)
Si L2,3
5000
4000
3000
2000
1000
0
80
90
100
110
120
Energy (eV)
Ec
Electron energy (eV)
130
140
Back Scatter
Electron
Back Scatter Electron peak (BSE)
Incident
Electrons
Intensity of Electrons N(E)
Reflection Electron Energy Loss Spectroscopy (REELS)
Ep
Probe Electron
Energy
Li spectra ~Li metal and Li oxyde (Li2O)~
[Core loss peak of Li (metal)]
[Core loss peak of Li (Li2O)]
500
3000
2 kV, 80 nA, CAE (Ep=10 eV)
2 kV, 80 nA, CAE (Ep=10 eV)
2500
Intensity (Arb. unit)
Intensity (Arb. unit)
400
300
200
100
1000
0
50
55
60
65
Loss energy (eV)
1
1500
500
0
45
2000
70
75
45
50
55
60
65
Loss energy (eV)
70
75
Li spectra ~Li (LiF) and Li (LiCl)~
Core loss peaks
of Li (LiF) and Li (LiCl)
Auger peaks
of Li (LiF) and Li (LiCl)
2000
30000
LiCl
LiF
Li 1s : 62.4 eV
1000
Li 1s
: 60.8eV
20000
N(E)/N(E)
Intensity (sounts)
25000
LiCl
LiF
15000
0
-1000
10000
Li KLL(LiCl) : 41eV
-2000
5000
Li KLL(LiF) : 34eV
0
40
-3000
50
60
70
Loss Energy(eV)
2
80
90
20
30
40
50
60
70
Electron Energy (eV)
80
90
100