Plasma Technology  

With the addition of an O2 plasma step (lower graph) the
C content of the Pd films is decreased below measuring
limits. A dual step process using the precursor and a
H2 plasma only (upper graph) leads to > 10 % C in the film.
(Pd grown on ALD Al2O3, plasma precleaned)

The O2 radicals in step 3 help to remove C.


TEM images of the Pd growth for the H2 only process (upper part)
and with the additional O2 step (lower part)
By the O2 plasma step a continous layer forms after fewer cycles.
The Pd Nanoparticles growth also got applicationss
(growth on 3 nm Al2O3, plasma precleaned)

GRC, C content and resisitivity
for the H2 plasma only (blue) and the H2 plus O2
plasma process (red).
The 3 step process is slower and leads to better films.

Pd growth by remote plasma ALD


Pd precursor: Pd(hfac)2


Pd hexafluoro acetylat acetonate



Why remote plasma ALD ?

A "remote plasma" makes sure, the substrates
are NOT in contact with the plasma !

The remote plasma just cracks molecules,
so that very reactive species can be used for
the growth process.

Such reactive species often enable a very
efficient plasma preclean/ conditioning of the
substrates, lead to cleaner films and lower
the deposition temperature.

In Oxford systems it is possible to run
ALD processes using
- the thermal only method
- ozone assisted processes
- remote plasma assisted processes
together without any hardware change.
Multiple step processes using all technologies
can be chosen from the software.

for the 3 step process @ 100 °C

GPC 0.13 Å/cycle

growth rate 0.3 Å/min - 1.8 nm/ hr
(not yet optimised for rate)

Density 11.7 g/ cm3

Resistivity ~24 µ ohm cm

C content < 2% (detection limit for XPS)

roughness for a 30 nm film < 1.4 nm (RMS)


with kind permission of TU Eindhoven
M J Weber et al
J. Phys. Chem. C, 2014, 118 (16), pp 8702–8711


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

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