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NANO EXPRESS Open Access
Characteristics of the Energetic Micro-
initiator Through Integrating Al/Ni Nano-
multilayers with Cu Film Bridge
Yuxin Zhang, Hongchuan Jiang*, Xiaohui Zhao, Yichao Yan, Wanli Zhang and Yanrong Li
Abstract
An energetic micro-initiator through integrating Al/Ni nano-multilayers with Cu film bridge was investigated in this study.
The Cu film bridge was initially fabricated with wet etching, and Al/Ni nano-multilayers were alternately deposited on the
surface of Cu film bridge by magnetron sputtering. The periodic layer structure of Al/Ni nano-multilayers was verified by
scanning electron microscopy. The exothermic reaction in Al/Ni nano-multilayers can be initiated with onset reaction
temperature as low as 503 K, and the total reaction heat is about 774.6 J/g. This energetic micro-initiator exhibited
improved performances with lower threshold voltage, smaller initiation energy, and higher explosion temperature
compared with Cu film bridge. An extra violent explosion phenomenon with longer duration time and larger quantities
of ejected product particles was detected on this energetic micro-initiator by high-speed camera. Overall, the electric
explosion performances of Cu film bridge can be improved evidently with the integration of Al/Ni nano-multilayers.
Keywords: Al/Ni multilayers, Micro-initiator, Nano-energetic, Electric explosion
Background
Metal-based nano-energetic materials have attracted a
lot of interests in recent years for their superior perfor-
mances in terms of fast energy release rate, large amount
of reaction heat, and more elements to choose [1–7].
Different nano-energetic materials based on intermetal-
lic reaction or thermic reaction were used in various ap-
plications including initiation of secondary reactions [8],
micro-initiator [9], welding and soldering [10], and air-
bags [11]. Many methods such as powder mixing, peri-
odically deposition of multilayers, sol-gel, and arrested
reactive milling have been introduced to fabricate nano-
energetic materials [12]. Among these methods, periodic
deposition of intermetallic multilayers provides a fascin-
ating structure by integrating the energetic layers with
microelectronic and mechanical systems (MEMS) to im-
prove the performances with compact size, and the per-
formances can be tuned easily by changing the number
of layers and bilayer thickness period.
The requirements of electric ignition devices with
miniaturization, low-energy initiation, and high perform-
ance have increased significantly in recent years; many ef-
forts have been devoted on integrating nano-energetic
materials with a film bridge initiator to improve ignition
process and enhance energy output [13–18]. Currently,
Al/Ni nano-multilayers are widely regarded as a type of
promising nano-energetic material to integrate with
MEMS for extremely high heating rates (105–106 K/S),
fast combustion propagation velocities up to 10 m/s, and
low onset reaction temperature (400–500 K) [19–22].
In this work, Al/Ni nano-multilayers were integrated
with Cu film bridge to form an energetic micro-initiator.
The structure and thermal properties of Al/Ni nano-
multilayers were characterized by scanning electron mi-
croscopy (SEM), different scanning calorimetry (DSC),
and X-ray diffraction (XRD). The effects of the presence
of Al/Ni nano-multilayers on the electric explosion per-
formances were systematically investigated.
Methods
The fabrication process flow of Cu/Al/Ni-integrated film
bridge is shown in Fig. 1. An alumina plate (0.5 mm
thick) was used as the substrate, and first, it was
* Correspondence: hcjiang@uestc.edu.cn
State Key Laboratory of Electronic Thin Films and Integrated Devices,
University of Electronic Science and Technology of China, Chengdu 610054,
China
© The Author(s). 2017 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0
International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and
reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to
the Creative Commons license, and indicate if changes were made.
Zhang et al. Nanoscale Research Letters  (2017) 12:38 
DOI 10.1186/s11671-016-1812-z
ultrasonic-cleaned sequentially by using acetone, alcohol,
and deionized water for 10 min. Then, the cleaned sub-
strate was blow-dried by nitrogen gas and treated at
383 K for 40 min for further drying.
A pure Cu target foil (99.995 wt%) with the size of
100 mm was applied as target for sputtering. 2-μm-thick
Cu layer was deposited on the alumina substrate with
sputtering temperature, pressure, and power of 373 K,
0.55 Pa, and 100 W, respectively. Afterwards, positive
photoresist was spin-coated onto the as-deposited Cu
film and patterned with photolithography through a de-
signed mask. Subsequently, FeCl3 solution was used to
wet etching the exposed Cu film at room temperature.
The dimension of the substrate is 10 mm (length) by
5 mm (width) by 0.5 mm (thickness). The dimension of
the Cu film bridge is 0.6 mm (length) by 0.6 mm (width)
by 2 μm (thickness).
After that, reversal photoresist was spin-coated onto
the Cu film bridge, which was patterned using photolith-
ography technology. The photoresist was exposed twice
to generate a reentrant profile. Then, 2-μm-thick Al/Ni
nano-multilayers with bilayer thickness of 200 nm (Al,
120 nm; Ni, 80 nm) were alternately deposited on the
Cu film bridge by magnetron sputtering. The deposition
parameters for Al layer and Ni layer were both set at
303 K, 0.4 Pa, and 100 W. The total thickness of Al/Ni
nano-multilayers was determined by the number of
layers. After removing the developed photoresist, two
Cu bound pads were stacked on both sides of the Al/Ni
nano-multilayers and lead wires were soldered for the
connection to the voltage source.
The cross-sectional morphology of the Al/Ni nano-
multilayers was characterized by SEM. The properties of
Al/Ni nano-multilayers on the heat energy generation
were measured by DSC, and the tests were carried out
at a temperature range from 323 to 973 K with the heat-
ing rate of 10 K/min in flowing nitrogen. The phase in-
formation of the Al/Ni nano-multilayers before and after
DSC experiments was determined by XRD.
The electric explosion properties of the samples were
tested by an electric ignition measurement system, as
shown in Fig. 2. The discharge capacitor (0.22 μF) was
used to apply voltage crossing micro-initiator. The
temperature characteristics were determined by an elec-
tric explosion temperature diagnosis mode based on the
“double-line atomic emission spectroscopy of a copper
element” [23, 24]. The electric explosion performance
and the reaction dynamic processes were recorded by
high-speed camera with 20,000 frames per second.
Results and Discussion
Figure 3 shows the cross-sectional image of the Al/Ni
nano-multilayers with bilayer thickness of 200 nm (Al,
Fig. 1 Fabrication process flow of Cu/Al/Ni-integrated film bridge
Fig. 2 Schematic diagram of electric ignition measurement system
Fig. 3 The cross-sectional image of the Al/Ni nano-multilayers with
bilayer thickness of 200 nm
Zhang et al. Nanoscale Research Letters  (2017) 12:38 Page 2 of 6
120 nm; Ni, 80 nm). We can see the well-aligned and
periodic layer structure of Al layers and Ni layers. The
planar layers remain continuous and homogenous,
which are beneficial for the intermetallic reaction be-
tween Al layers and Ni layers to release energy.
The thermal properties of Al/Ni nano-multilayers were
investigated by DSC, as shown in Fig. 4. Three exother-
mic peaks can be identified during the heating process.
The onset reaction temperature for the first exothermic
peak is 503 K, which is less than the melting point of
both Al and Ni. The reaction heat of Al/Ni nano-
multilayers was calculated through integrating the
positive exothermic heat flow which is about 774.6 J/g
and almost no mass loss during the test. The low onset
reaction temperature and high exothermic heat is con-
ductive to improve the electric explosion process of Cu
film bridge. Note that the exothermic heat is well below
the maximum theoretical value 1390 J/g [25] and this
might be caused by the deviation from the optimum
mass ratio and the inevitable surface contamination dur-
ing the transfer of samples. The phase information of
Al/Ni multilayers before and after DSC experiment is
detected by XRD, as shown in Fig. 5. Before the reaction,
Al and Ni in Al/Ni nano-multilayers are both present in
Fig. 4 TG/DSC curves of Al/Ni nano-multilayers at the heating rate of 10 K/min in flowing nitrogen
Fig. 5 XRD results of the Al/Ni nano-multilayers with bilayer thickness of 200 nm before and after reaction
Zhang et al. Nanoscale Research Letters  (2017) 12:38 Page 3 of 6
crystalline form. While after the DSC test, all major
peaks correspond to AlNi compound, indicating that
AlNi is the dominant product of the intermetallic reac-
tion between Al layers and Ni layers.
When the voltage is applied crossing the bridge area,
instantly increasing current density causes the
temperature and resistance of bridge to rise rapidly, and
the voltage keeps on increasing and reaches the maximal
value when the bridge begin to vaporize. Thus, the max-
imal voltage is defined as the threshold voltage. The typ-
ical experimental results of the firing data obtained in
the electric explosion tests are shown in Fig. 6. The
threshold voltage is measured to be 1580 V for Cu film
bridge and 1100 V for Cu/Al/Ni-integrated film bridge.
The threshold voltage is reduced around 30% when 2-
μm-thick Al/Ni nano-multilayers are integrated with Cu
film bridge. The required energy to initiate the Cu film
bridge and Cu/Al/Ni-integrated film bridge can be cal-
culated by integrating the product of voltage and current
during the electric explosion process. Thus, the initiation
energy is about 358.1 mJ for Cu film bridge and about
103.9 mJ for Cu/Al/Ni-integrated film bridge. These re-
sults indicate that the energy released by the intermetal-
lic reaction in Al/Ni nano-multilayers can decrease the
Fig. 6 Voltage-current histories for Cu film bridge (a) and Cu/Al/Ni-integrated film bridge (b) during the explosion processes
Zhang et al. Nanoscale Research Letters  (2017) 12:38 Page 4 of 6
threshold voltage and initiation energy of Cu film bridge
significantly. Specifically, the generated energy of Al/Ni
nano-multilayers can be easily tuned by altering the
number of layers, which provide a simple method to
tailor the electric explosion performances of energetic
micro-initiator.
Figure 7 shows the electric explosion temperature
variation of Cu film bridge and Cu/Al/Ni-integrated
film bridge under 1800 V discharge voltage. After
applying voltage, the explosion temperature reaches
the maximum at 4465 K for Cu film bridge and
5300 K for Cu/Al/Ni-integrated film bridge. This in-
crement of the maximum explosion temperature of
Cu/Al/Ni-integrated film bridge confirms that the
presence of Al/Ni nano-multilayers can increase the
total heat energy generated on the Cu film bridge. It
is believe that high explosion temperature is benefi-
cial for the expansion of Cu plasma and the
consequent improvement of electric explosion per-
formances [14].
The electric explosion performances and reaction dy-
namic processes of Cu film bridge and Cu/Al/Ni-inte-
grated film bridge were recorded simultaneously by
high-speed camera, as shown in Fig. 8. The time interval
between adjacent pictures is 50 μs, and the specific
flame structures in different electric explosion stages
have been observed. After triggering, an electric explo-
sion phenomenon accompanied with a bright flash was
observed on Cu film bridge, and the duration time of Cu
film bridge is about 300 μs. While for Cu/Al/Ni-inte-
grated film bridge, a more fierce combustion process
with larger quantities of ejected product particles is ob-
served. The light duration time is over 1 ms, which is
much longer than that of Cu film bridge. These results
indicate that the intermetallic reaction in Al/Ni nano-
multilayers is triggered during the electric explosion
Fig. 7 Temperature variation histories for Cu film bridge and Cu/Al/Ni-integrated film bridge during the explosion processes
Fig. 8 High-speed camera observation of electric explosion processes for Cu film bridge (a) and integrated film bridge (b)
Zhang et al. Nanoscale Research Letters  (2017) 12:38 Page 5 of 6
process, and the electric explosion performances of Cu
film bridge can be improved substantially. The more vio-
lent explosion phenomenon of Cu/Al/Ni-integrated film
bridge is corresponded well with those results of electric
explosion temperature tests.
Conclusions
In this work, Al/Ni nano-multilayers were integrated
with Cu film bridge as nano-energetic material and the
electric explosion performances of energetic micro-
initiator were investigated. The exothermic reaction in
Al/Ni nano-multilayers could be initiated with a quite
low onset reaction temperature of 503 K, and the total
reaction heat was calculated to be 774.6 J/g. The pres-
ence of Al/Ni nano-multilayers on Cu film bridge can
improve the maximum of electric explosion temperature
as well as decrease the threshold voltage and initiation
energy. Compared to Cu film bridge, more fierce com-
bustion process with larger quantities of ejected product
particles and longer duration time was observed on Cu/
Al/Ni-integrated film bridge. In general, the integration
of Al/Ni nano-multilayers with Cu film bridge can im-
prove the electric explosion performances evidently, and
the small size of energetic micro-initiator is also benefi-
cial to realize reliable and compact ignition.
Abbreviations
MEMS: Microelectronic and mechanical systems; SEM: Scanning electron
microscopy; TG/DSC: Thermogravimetric analysis/different scanning
calorimetry; XRD: X-ray diffraction
Acknowledgements
This work was supported by the military support project fund (no. JPPT-125-
5-161) and science and technology innovation foundation of Sichuan (no.
2014-083).
Authors’ Contributions
ZYX carried out the experimental work and characterization measurement
and wrote the paper. YYC assisted in the measurement and data analysis.
JHC and ZXH made corrections to the manuscript. ZWL and LYR supervised
the whole work. All authors read and approved the final manuscript.
Competing Interests
The authors declare that they have no competing interests.
Received: 12 November 2016 Accepted: 23 December 2016
References
1. Kim SB, Kim KJ, Cho MH, Kim JH, Kim KT, Kim SH (2016) Micro- and
nanoscale energetic materials as effective heat energy sources for
enhanced gas generators. ACS Appl Mater Inter 8:9405–9412
2. Rogachev AS, Vadchenko SG, Baras F, Politano O, Rouvimov S, Sachkova NV,
Mukasyan AS (2014) Structure evolution and reaction mechanism in the Ni/
Al reactive multilayer nanofoils. Acta Mater 66:86–96
3. Glavier L, Taton G, Ducéré J, Baijot V, Pinon S, Calais T, Estève A et al (2015)
Nanoenergetics as pressure generator for nontoxic impact primers: comparison of Al/
Bi2O3, Al/CuO, Al/MoO3 nanothermites and Al/PTFE. Combust Flame 162:1813–1820
4. Shen J, Qiao Z, Wang J, Zhang K, Li R, Nie F, Yang G (2014) Pressure loss
and compensation in the combustion process of Al–CuO nanoenergetics
on a microheater chip. Combust Flame 161:2975–2981
5. Dreizin EL (2009) Metal-based reactive nanomaterials. Prog Energ Combust
35:141–167
6. Zhang D, Li X (2015) Fabrication and kinetics study of nano-Al/NiO thermite
film by electrophoretic deposition. J Phys Chem A 119:4688–4694
7. Xu D, Yang Y, Cheng H, Li YY, Zhang K (2012) Integration of nano-Al with
Co3O4 nanorods to realize high-exothermic core–shell nanoenergetic
materials on a silicon substrate. Combust Flame 159:2202–2209
8. Morris CJ, Mary B, Zakar E, Barron S, Fritz G, Knio O, Weihs TP et al (2010)
Rapid initiation of reactions in Al/Ni multilayers with nanoscale layering. J
Phys Chem Solids 71:84–89
9. Yan Y, Shi W, Jiang H, Cai X, Deng X, Xiong J, Zhang W (2015)
Characteristics of the energetic igniters through integrating B/Ti nano-
multilayers on TaN film bridge. Nanoscale Res Lett 10:1–6
10. Shen J, Chan YC (2009) Research advances in nano-composite solders.
Microelectron Reliab 49:223–234
11. Baginski TA, Taliaferro SL, Fahey WD (2001) Novel electroexplosive device
incorporating a reactive laminated metallic bridge. J Propuls Power 17:184–189
12. Zhou X, Torabi M, Lu J, Shen R, Zhang K (2014) Nanostructured energetic
composites: synthesis, ignition/combustion modeling, and applications. ACS
Appl Mater Inter 6:3058–3074
13. Qiu X, Tang R, Liu R, Huang H, Guo S, Yu H (2012) A micro initiator realized
by reactive Ni/Al nanolaminates. J Mater Sci Mater Electron 23:2140–2144
14. Zhou X, Shen R, Ye Y, Zhu P, Hu Y, Wu L (2011) Influence of Al/CuO reactive
multilayer films additives on exploding foil initiator. J Appl Phys 110:94505
15. Wang J, Jiang X, Zhang L, Qiao Z, Gao B, Yang G, Huang H (2015) Design and
fabrication of energetic superlattice like-PTFE/Al with superior performance
and application in functional micro-initiator. Nano Energy 12:597–605
16. Taton G, Lagrange D, Conedera V, Renaud L, Rossi C (2013) Micro-chip
initiator realized by integrating Al/CuO multilayer nanothermite on
polymeric membrane. J Micromech Microeng 23:3210–3216
17. Rossi C, Zhang K, Esteve D, Alphonse P, Tailhades P, Vahlas C (2007)
Nanoenergetic materials for MEMS: a review. J Microelectromech S 16:919–931
18. Tanaka S, Kondo K, Habu H, Itoh A, Watanabe M, Hori K, Esashi M (2008)
Test of B/Ti multilayer reactive igniters for a micro solid rocket array
thruster. Sensors Actuators A Phys 144:361–366
19. Gavens AJ, Van Heerden D, Mann AB, Reiss ME, Weihs TP (2000) Effect of
intermixing on self-propagating exothermic reactions in Al/Ni nanolaminate
foils. J Appl Phys 87:1255
20. Rogachev AS, Vadchenko SG, Baras F, Politano O, Rouvimov S, Sachkova NV,
Grapes MD et al (2016) Combustion in reactive multilayer Ni/Al nanofoils:
experiments and molecular dynamic simulation. Combust Flame 166:158–169
21. Rogachev AS, Mukasyan AS (2010) Combustion of heterogeneous nanostructural
systems (review). Combustion Explosion & Shock Waves 46:243–266
22. SR A (2008) Exothermic reaction waves in multilayer nanofilms. Russ Chem Rev 77:21
23. Guo R, Hu Y, Shen R, Ye Y, Wu L (2012) A micro initiator realized by
integrating KNO3@CNTs nanoenergetic materials with a Cu microbridge.
Chem Eng J 211–212:31–36
24. Zhu P, Shen R, Fiadosenka NN, Ye Y, Hu Y (2011) Dielectric structure
pyrotechnic initiator realized by integrating Ti/CuO-based reactive multilayer
films. J Appl Phys 109:84523
25. Fischer SH, Grubelich MC (1999) Theoretical energy release of thermites,
intermetallics, and combustible metals, Office of Scientific & Technical
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Characteristics of the Energetic Micro-initiator Through Integrating Al/Ni Nano-multilayers with Cu Film Bridge

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