<s>
A	O
piezoelectric	O
microelectromechanical	B-Architecture
system	I-Architecture
(	O
piezoMEMS	B-Algorithm
)	O
is	O
a	O
miniature	O
or	O
microscopic	O
device	O
that	O
uses	O
piezoelectricity	O
to	O
generate	O
motion	O
and	O
carry	O
out	O
its	O
tasks	O
.	O
</s>
<s>
It	O
is	O
a	O
microelectromechanical	B-Architecture
system	I-Architecture
that	O
takes	O
advantage	O
of	O
an	O
electrical	O
potential	O
that	O
appears	O
under	O
mechanical	O
stress	O
.	O
</s>
<s>
PiezoMEMS	B-Algorithm
can	O
be	O
found	O
in	O
a	O
variety	O
of	O
applications	O
,	O
such	O
as	O
switches	O
,	O
inkjet	O
printer	O
heads	O
,	O
sensors	O
,	O
micropumps	O
,	O
and	O
energy	O
harvesters	O
.	O
</s>
<s>
Interest	O
in	O
piezoMEMS	B-Algorithm
technology	O
began	O
around	O
the	O
early	O
1990s	O
as	O
scientists	O
explored	O
alternatives	O
to	O
electrostatic	O
actuation	O
in	O
radio	O
frequency	O
(	O
RF	O
)	O
microelectromechanical	B-Architecture
systems	I-Architecture
(	O
MEMS	B-Architecture
)	O
.	O
</s>
<s>
For	O
RF	B-Algorithm
MEMS	I-Algorithm
,	O
electrostatic	O
actuation	O
specialized	O
high	O
voltage	O
charge	O
pump	O
circuits	O
due	O
to	O
small	O
electrode	O
gap	O
spacing	O
and	O
large	O
driving	O
voltages	O
.	O
</s>
<s>
PiezoMEMS	B-Algorithm
have	O
been	O
applied	O
to	O
various	O
different	O
technologies	O
from	O
switches	O
to	O
sensors	O
,	O
and	O
further	O
research	O
have	O
led	O
to	O
the	O
creation	O
of	O
piezoelectric	O
thin	O
films	O
,	O
which	O
aided	O
in	O
the	O
realization	O
of	O
highly	O
integrated	O
piezoMEMS	B-Algorithm
devices	O
.	O
</s>
<s>
The	O
first	O
reported	O
piezoelectrically	O
actuated	O
RF	B-Algorithm
MEMS	I-Algorithm
switch	O
was	O
developed	O
by	O
scientists	O
at	O
the	O
LG	O
Electronics	O
Institute	O
of	O
Technology	O
in	O
Seoul	O
,	O
South	O
Korea	O
in	O
2005	O
.	O
</s>
<s>
The	O
researchers	O
designed	O
and	O
actualized	O
a	O
RF	B-Algorithm
MEMS	I-Algorithm
switch	O
with	O
a	O
piezoelectric	O
cantilever	O
actuator	O
that	O
had	O
an	O
operation	O
voltage	O
of	O
2.5	O
volts	O
.	O
</s>
<s>
This	O
experiment	O
was	O
part	O
of	O
a	O
decades-long	O
research	O
investment	O
effort	O
at	O
ARL	O
to	O
improve	O
the	O
use	O
of	O
PZT	O
thin	O
film	O
technology	O
for	O
piezoMEMS	B-Algorithm
.	O
</s>
<s>
Other	O
piezoMEMS-related	O
work	O
included	O
developing	O
a	O
piezoelectric	O
microphone	O
based	O
on	O
PZT	O
thin	O
films	O
,	O
creating	O
new	O
integrated	O
surface	O
micromachining	O
processes	O
for	O
RF	B-Algorithm
MEMS	I-Algorithm
to	O
incorporate	O
thin	O
film	O
PZT	O
actuators	O
,	O
providing	O
the	O
first	O
experimental	O
demonstration	O
of	O
monolithically	O
integrated	O
piezoMEMS	B-Algorithm
RF	O
switches	O
with	O
contour	O
mode	O
filters	O
,	O
and	O
demonstrating	O
the	O
feasibility	O
of	O
vibrational	O
energy	O
harvesting	O
using	O
thin	O
film	O
PZT	O
MEMS	B-Architecture
.	O
</s>
<s>
There	O
exists	O
three	O
primary	O
approaches	O
to	O
realizing	O
PiezoMEMS	B-Algorithm
devices	O
:	O
</s>
<s>
PiezoMEMS	B-Algorithm
use	O
two	O
principal	O
crystal	O
structures	O
,	O
the	O
wurtzite	O
and	O
perovskite	O
structures	O
.	O
</s>
<s>
PiezoMEMS	B-Algorithm
still	O
face	O
many	O
difficulties	O
that	O
impede	O
its	O
ability	O
to	O
be	O
successfully	O
commercialized	O
.	O
</s>
<s>
For	O
instance	O
,	O
the	O
success	O
of	O
depositing	O
uniform	O
films	O
of	O
piezoelectrics	O
still	O
depend	O
heavily	O
on	O
the	O
use	O
of	O
appropriate	O
layers	O
of	O
proper	O
nucleation	B-Algorithm
and	O
film	O
growth	O
.	O
</s>
