AAO, anodic aluminium oxide, is a well-ordered
anoporous template, which is prepared by use
of an electrochemical technique and a thin piece
of Al as the anode. AAO-templates are widely used
for nanomaterials and nanotechnology.
The aspect ratio of the holes can be up 1000!
(hole diameter from 50-100nm and thickness of
template 70 micrometer) The figure above
presents a typical AAO before and
after ALD deposition.
ALD-ZnO, SiO2 and SiN can go through
the holes and form nano-tubes.

70 nm wide tube
100 µm long

highly conformal ZnO growth
with optimised process conditions

precursor: DEZ
di ethyl zinc
non metal precursor: H2O

temperature controlled vapour draw

dose control by fast pulse ALD valve

deposition temperature: 50° - 200° C

cycle time 4 sec
thickness per cycle 1.9 A
(saturated dose)

resistivity 5 x E-3 ohm cm

C impurity < 2 at % at 150° C

uniformity: ± 1% (100 mm)

repeatability: ± 1%

refractive index: 1.90 - 1.95

Zn:O 1:1

GRC vs deposition (table) temperature

Growth rate per cycle and refractive index
vs DEZ dose time at 150° C

ALD schematic
valve between remote ICP source
and chamber,
spectroscopic ellipsometry optional

AES analysis shows Zn:O 1:1 and C < 2 at %

"Flex AL" for
Atomic Layer Deposition based on the
Plasmalab System 100

"OpAL" for
Atomic Layer Deposition based on the
Plasmalab 80 Plus