Thermally induced crystallization in NbO2thin films.
Niobium dioxide can exhibit negative differential resistance (NDR) in metal-insulator-metal (MIM) devices, which has recently attracted significant interest for its potential applications as a highly non-linear selector element in emerging nonvolatile memory (NVM) and as a locally-active element in neuromorphic circuits. In order to further understand the processing of this material system, we studied the effect of thermal annealing on a 15 nm thick NbO2thin film sandwiched inside a nanoscale MIM device and compared it with 180 nm thick blanket NbOx(x = 2 and 2.5) films deposited on a silicon dioxide surface as references. A systematic transmission electron microscope (TEM) study revealed a similar structural transition from amorphous to a distorted rutile structure in both cases, with a transition temperature of 700 °C for the NbO2inside the MIM device and a slightly higher transition temperature of 750 °C for the reference NbO2film. Quantitative composition analysis from electron energy loss spectroscopy (EELS) showed the stoichiometry of the nominal 15 nm NbO2layer in the as-fabricated MIM device deviated from the target 1:2 ratio because of an interaction with the electrode materials, which was more prominent at elevated annealing temperature.
Hewlett Packard Labs, 1501 Page Mill Rd, Palo Alto, CA 94304, USA.
Jiaming
J
Zhang
Hewlett Packard Labs, 1501 Page Mill Rd, Palo Alto, CA 94304, USA.
Kate J
KJ
Norris
Hewlett Packard Labs, 1501 Page Mill Rd, Palo Alto, CA 94304, USA.
Gary
G
Gibson
Hewlett Packard Labs, 1501 Page Mill Rd, Palo Alto, CA 94304, USA.
Dongxue
D
Zhao
Hewlett Packard Labs, 1501 Page Mill Rd, Palo Alto, CA 94304, USA.
Katy
K
Samuels
Hewlett Packard Labs, 1501 Page Mill Rd, Palo Alto, CA 94304, USA.
Minxian Max
MM
Zhang
Department of Electrical and Computer Engineering, University of Massachusetts, Amherst, Massachusetts 01003, USA.
J Joshua
JJ
Yang
Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA.
Joonsuk
J
Park
Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA.
Robert
R
Sinclair
Hewlett Packard Labs, 1501 Page Mill Rd, Palo Alto, CA 94304, USA.
Yoocharn
Y
Jeon
Hewlett Packard Labs, 1501 Page Mill Rd, Palo Alto, CA 94304, USA.
Zhiyong
Z
Li
Hewlett Packard Labs, 1501 Page Mill Rd, Palo Alto, CA 94304, USA.
R Stanley
RS
Williams
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