Supplemental Information
Evaluating Tantalum Oxide Stoichiometry and
Oxidation States for Optimal Memristor Performance
Michael T. Brumbach1*, Patrick R. Mickel2, Andrew J. Lohn2, Alex Mirabal1, Michael Kalan1,
James E. Stevens3, Matthew J. Marinella2
1
2
Materials Characterization and Performance
Radiation Hard CMOS Technology and Advanced Device Development
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MESAFab Operations 2
Sandia National Laboratories, Albuquerque, NM 87185, U.S.A.
*mtbrumb@sandia.gov
NOTES ON PEAK FITTING.
Some conditions of the fitting require explanation. The Ta 4f 7/2 and 5/2 peaks of Ta5+ were not held
to 4:3 area intensity ratio. This was performed since these peaks often dominated the spectral envelope.
Constraints placed on the area ratio of these two intense peaks overwhelmed the fitting of the substoichiometric species at lower binding energy. Consequently, the intensity ratios for these two peaks
were not fixed, but were often close to the theoretical 4:3 ratio. Sub-stoichiometric peaks were given a
Gaussian/Lorenztian (70/30) lineshape with fixed FWHM.
1
Carbon Atomic Concentration (%)
30
27
24
21
18
15
12
9
6
3
35
30
25
20
15
10
5
0
0
1
2
3
4
5
6
7
Wafer Number
31
27
25
wafer 1
23
21
19
29
27
25
wafer 2
23
21
19
0
6
12
18
24
Diced Sample # Across Wafer
30
6
12
18
24
Diced Sample # Across Wafer
wafer 4
23
21
19
6
12
18
24
Diced Sample # Across Wafer
30
wafer 3
23
21
6
12
18
24
Diced Sample # Across Wafer
30
31
29
27
25
wafer 5
23
21
19
0
25
0
Carbon Atomic Concentration (%)
25
Carbon Atomic Concentration (%)
27
27
30
31
29
29
19
0
31
Carbon Atomic Concentration (%)
31
Carbon Atomic Concentration (%)
29
Carbon Atomic Concentration (%)
Carbon Atomic Concentration (%)
31
29
27
25
wafer 6
23
21
19
0
6
12
18
24
Diced Sample # Across Wafer
30
0
6
12
18
24
Diced Sample # Across Wafer
30
Figure SI.1. Carbon concentration is shown for Wafers 1 through Wafer 6. The more oxidized TaOx
thin films tended to show lower carbon levels than the more metallic-like thin films. Also shown is the
carbon concentration across each respective wafer. There did not appear to be any systematic trends in
carbon content across a given wafer.
2
Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia
Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of
Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.
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