Electrically Controlled Lenses based on GaN/AlN/SiC/GaN and Their
Capabilities of Being Used in High-Temperature and Aggressive
Environments
E. A. Panyutin
a
Ioffe Institute, Polytechnicheskaya 29, St-Petersburg, Russia
Keywords: Black Smokers; AlN/SiC-Structures, Electrically Controlled Lenses, Aspherization.
Abstract: Possible application of the GaN/AlN/SiC/GaN-structures for manufacturing of active optical elements
designed for operation in extreme conditions and, in particular, for investigation of oceanic hydrothermal
sources (the "black smokers") is considered in the research. Advances in epitaxial III-nitride technologies in
terms of obtaining "thick" AlN-layers and multilayer heterostructures make it possible to formulate a new
approach to creating electrically controlled lenses, in which the longitudinal piezo effect (in the direction of
the optical axis) is assumed to be implemented. In contrast to the radial-oriented transverse piezo effect
previously applied by scientists in order to create bending deformations in bimorph membrane-type
microlenses, the proposed design uses thin transparent conducting GaN-layers as control electrodes. As a part
of the stated concept, an algorithm is also developed, and simulations are performed in order to study changes
in the magnitude and nature of the curvature of the outer GaN surface, depending both on changes in
temperature and changes in control voltage. It is assumed that this design solution of the lens will allow for
adaptive thermal compensation of its optical parameters with a possible change of ambient temperature in a
wide range (up to 1000 ºC).
1 INTRODUCTION
Underwater geothermal sources, formed as a result of
the hot mantle interaction with ocean water
penetrating the crust through cracks, and known as
"black smokers", are of exceptional interest, and not
only from a geological point of view. Superheated
geothermal water with a temperature of up to 400OC,
under high pressure, enriched with sulfides of many
metals and volcanic gases (hydrogen sulfide,
ammonia, methane), is a favorable environment for
the emergence of unique biocenoses without
photosynthesis, where sulfides are consumed by
chemosynthesizing bacteria and which, in turn, serve
as the basis for unique ecosystems (mollusks, crabs,
worms)
(Zeppilli, et al., 2018; Zeng, et al., 2021;
Yamamoto, et al., 2018).
Studies of such ecosystems are
largely based on the analysis of images delivered by
underwater vehicles, so it is important to develop new
optical systems for operation in high-temperature and
aggressive environments.
a
https://orcid.org/0000-0002-6414-2927
At the same time, recent advances in epitaxial
technologies for wide-gap materials (SiC, GaN, AlN)
have stimulated research focused on creating
autonomous robotic devices, including underwater
ones, for operation under extreme temperature
conditions.
Many years of work in the field of creating the
element base of high-temperature SiC electronics led,
as a result, to the creation of the first simple
microcircuits, which, nevertheless, are operational at
temperatures of up to 500ºC
(Tian, et al., 2017;
Kargarrazi, et al., 2018; Kargarrazi, et al., 2016; Spry, et al.,
2018)
and even up to 800ºC (Neudeck, et al., 2017) to
the formulation of new approaches in the technology
of obtaining integrated power devices
(Ilicheva, et al.,
2018).
At the same time, work in the field of wide-gap
III-nitrides made it possible to make significant
progress in the field of building high-temperature
functional electronics, which combines numerous and
diverse sensors and micromechanical devices
(Dong,
et al., 2019; Gavrilov, et al., 2018; Umeda, et al., 2013),
and research is also underway in the field of single-
272
Panyutin, E.
Electrically Controlled Lenses Based on GaN/AlN/SiC/GaN and Their Capabilities of Being Used in High-Temperature and Aggressive Environments.
DOI: 10.5220/0012008700003536
In Proceedings of the 3rd International Symposium on Water, Ecology and Environment (ISWEE 2022), pages 272-275
ISBN: 978-989-758-639-2; ISSN: 2975-9439
Copyright
c
 2023 by SCITEPRESS – Science and Technology Publications, Lda. Under CC license (CC BY-NC-ND 4.0)

crystal integration of AlN sensors with matrix SiC
structures
(Panyutin, et al., 2020).
A natural continuation of this series could be
creation of an element base for high-temperature
optics (including those for operation in aggressive
environments), which would be based on transparent
functional materials to perform compensatory
functions under thermal cycling conditions.
2 MATERIALS AND
TECHNOLOGY
Taking into account that not only the exceptional
thermal stability (>1500ºC), chemical indifference
and high mechanical strength, but also the
piezoelectric activity of AlN along the polar direction
(Akiyama, et al., 2009), makes this material, along with
SiC, extremely attractive for high temperature
applications
(Fraga, et al., 2014).
The recently developed HVPE (hydride-chloride
vapor phase epitaxy) technologies make it possible to
obtain sufficiently thick (>300 mcm) AlN layers
(Kukushkin, 2019), which provides ample
opportunities for their use in the manufacturing of flat
optical elements, while the use of laser or ion
micromachining technologies makes it possible to
form curvilinear surfaces necessary to obtain various
microlenses. Moreover, it is obvious that the
possibilities of heteroepitaxy also make it possible to
create bimorph elements for which only one of the
materials is a piezoelectric, for example, SiC/AlN
structures. At the same time, it is also obviously
desirable to use lenses and multi-lens systems with
electrically controlled characteristics, which would
make it possible to level the negative effect of
temperature changes on the quality of the formed
image.
The technological implementation of such a
structure (Figure 1) is possible, for example, using the
epitaxial production of an AlN layer on a preformed
curved surface of an insulating hexagonal SiC
substrate, and the production of doped thin (<1 mcm)
conductive GaN layers as external transparent
electrodes (for more details, see
(Panyutin, et al., 2019).
Thus, the control voltage U0 applied to these GaN
electrodes causes, in accordance with the inverse
piezoelectric effect, a change in the local thickness of
the bimorph SiC/AlN lens AlN layer and can be used
to compensate for the size due to possible thermal
expansion. However, a side effect of the AlN
piezodeformation may cause the outer surface to
deviate from the original sphericity. In this work, the
main emphasis will be placed on the study of possible
aspherization in the process of changing the control
voltage, which is of undoubted interest for the
development of tunable aspherical.
Figure 1: AlN/SiC lens profile for different variants
of curvature of the internal heterointerface.
3 COMPUTER SIMULATION
AND CALCULATION DETAILS
It is known that the equation of the sphere surface
geodesic line in Cartesian coordinates for the section
corresponding to y=0 can be represented as:
22 2 2
()
oo
zx z R r R x=−±− 
(1)
Here z is the coordinate of the lens surface, 2r
o
is its
diameter, R is the radius of the surface curvature,
uniquely related to its focal length. Based on this
formula, it is easy to obtain the dependence of the lens
piezocomponent thickness w
2
for y=0 on the x
coordinate:
22 22
22 2
() ...
o
wx R x R r=−−−+
22 22
11o
Rx Rr+− −
(2)
In accordance with Figure 1, here R
1
is the
technologically specified sphere radius of the
SiC/AlN heterointerface; R
2
is the radius of the
AlN/GaN surface, which depends both on the
external temperature T and on the external control
voltage U
0
. Then the thickness w
1
(x) of the composite
lens “piezo-indifferent” component can be
represented as
Electrically Controlled Lenses Based on GaN/AlN/SiC/GaN and Their Capabilities of Being Used in High-Temperature and Aggressive
Environments
273

22 22
111
()
oo
wx d R x R r=− − −
, (3)
where d
o
is the thickness of the composite lens at |x|=
r
o
.
The voltage U
0
supplied from an external source
to the GaN electrodes will be redistributed between
the SiC and AlN dielectric layers
011 21
(, ) (, )
ww
UUxRUxR=+
(4)
and
21
2( ) 0
11 21
(, )
(, ) (, )
wx
wxR
UU
wxR w xR
=⋅
+
(5)
where |x| = r, and R
1
is included as a parameter. It can
be shown that the change in the z-coordinate of the
AlN surface with a change in the control voltage
22
233 0
12
1()
()
4()()
AlN
wx
zx d U
wx wx
ε−
Δ=⋅ ⋅ ⋅Δ
π+
(6)
where d
33
AlN
= 3.9 ·10
-9
mm/V [14] is the component
of the AlN piezoelectric coefficient tensor and ε
2
is
the permittivity.
The degree of surface aspherization (i.e., its
deviation from a spherical profile) can also be
estimated by introducing the local curvature of the
outer surface,
()
()
3
2
22
0
2
(, )
1
dzdx
Kx U
dz dx
Δ=
+
(7)
The family of curves demonstrating the deviation of
the AlN surface from the sphere for different values
of the radii of the AlN/SiC interface is shown in
Figure 2.
The local radius of curvature of an aspherical surface is
obviously not a constant and is defined as the reciprocal of
the local curvature, i.e.
1
0
(, )
asp
R
xU K
−
Δ=
(8)
The deviation of the surface from spherical can also
be characterized by introducing the coefficient of
relative asphericity
0
(, )
A
sp Asp Sp
KxU R RΔ=
(9)
Its dependence on the radius of curvature of the
AlN/SiC interface (the case of positive values of the
radius) is shown in Figure 3.
All calculations were made in the MATLAB.
Figure 2: Radial dependence of the local curvature of the
outer AlN surface for different curvature radii of the
AlN/SiC boundary.
Figure 3: Dependence of the aspherization coefficient of the
AlN surface on the radius of curvature of the
heterointerface.
4 CONCLUSION
New opportunities that open up in connection with
the further improvement of technologies for obtaining
high-transparency epitaxial quasi-bulk aluminum
nitride and “thick” AlN/SiC heterostructures make it
possible to develop new types of heat-resistant optical
lenses with a controlled aspherization function, which
can be useful for the further development of multi-
lens aspherical objectives.
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274

REFERENCES
Akiyama, M., Kamohara, T., Kano, K., Teshigahara, A.,
Takeuchi, Y., and Kawahara N. (2009). Enhancement
of piezoelectric response in scandium aluminum nitride
alloy thin films. Adv. Mater, 21. [14]
Dong W., X Ji, W Wang, T Li, J Huang (2019).
Investigation of surface acoustic waves anisotropy on
high-quality AlN/Sapphire grown by hydride vapor
phase epitaxy
Mater. Res. Express, 6:095903. [10]
Gavrilov G.A., Kapralov A.F., Muratikov K.L., Panyutin
E.A., Sotnikov A.V., Sotnikova G.Yu., Sharofidinov
Sh.Sh. (2018). Standing the pyroelectric effect in AlN
epilayers.
Tech.Phys. Lett, 44(8):709-712. [11]
Fraga M.A., Furlan H., Pessoa R.S., Massi M., (2014).
Wide bandgap semiconductor thin films for
piezoelectric and piezoresistive MEMS sensors applied
at high temperatures: an overview.
Microsyst. Technol.,
20: 9-21. [15]
Ilicheva T. P., Panyutin, E. A. (2018). Integrated
technologies and the problem of creation of large-area
silicone carbide devices for high-power converters
MATEC Web of Conferences, 239:01019. [9]
Kargarrazi, S., Lanni, L., Zetterling, C.M. (2016). A study
on positive-feedback configuration of a bipolar SiC
high temperature operational amplifier Solid-State
Electron., 116:33-37. [6]
Kargarrazi, S., Elahipanah, H., Rodriguez S., and
Zetterling, C. (2018). 500 °C, High Current Linear
Voltage Regulator in 4H-SiC BJT Technology.
IEEE
Electron Device Letters
, 39(4):548-551. [5]
Kukushkin, S.A., Sharofidinov, Sh.Sh. (2019). A New
Method of Growing AlN, GaN, and AlGaN Bulk
Crystals Using Hybrid SiC/Si Substrates. Phys. Solid
St., 61(12):2342-2347. [16]
Neudeck, P.J., Spry, D.J., Chen, L., Prokop, N.F. (2017).
Demonstration of 4H-SiC digital integrated circuits
above above 800° C.
IEEE Electron Device Lett,
38(8):1082-1085. [8]
Panyutin, E.A., Shmatov M.L. (2019). Capabilities of
GaN/AlN/GaN structures as high-intensity pyroelectric
laser sensors. Quantum Electronics, 49(11):1078-1082.
[17]
Panyutin, E.A., Sharofidinov, S.S., Orlova, T.A., Snytkina,
S.A., Lebedev, A.A. (2020). Biplanar epitaxial
AlN/SiC/(n, p) SiC structures for high-temperatures
functional electronic devices.
Tech. Phys., 60(3):428-
433. [13]
Umeda K., Kavai H. (2013). Piezoelectric properties of
ScAlN thin films for piezo-MEMS devices.
Proc. IEEE
26
th
Int. Conf. Micro Electro Mech Syst (MEMS), pages
733-736. [12]
Spry, D.J., Neudeck, P.J., Lukco, D., Chen, L., Krasowski,
M.J., Prokop, N.F., Chang, K.W. (2018). Prolonged
500ºC operation of 100+ transistor silicon carbide
integrated circuits.
Material Science Forum, pages
949-952. [7]
Tian, Y., Zetterling, C.M. (2017). A fully integrated silicon-
carbide sigma-delta modulator operating up to 500ºC.
IEEE Trans. Electron Devices, 64(7):2782-2788. [4]
Yamamoto, M., Nakamura, R., Takai, K. (2018). Deep-Sea
Hydrothermal Fields as Natural Power Plants
ChemElectroChem., 5(16):2162-2166. [3]
Zeng, X., Alain, K. & Shao, Z. (2021). Microorganisms
from deep-sea hydrothermal vents.
Mar Life Sci
Technol
., 3:204–230. [2]
Zeppilli, D., Leduc, D., Fontanier, C.
et al. (2018).
Characteristics of meiofauna in extreme marine
ecosystems: a review.
Mar Biodiv., 48:35–71. [1]
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Environments
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