Plasma Technology  

Varying O2 plasma exposure
shifts between Pt and PtO2.

Purely thermal Pt ALD growth is hard to achieve
as no Pt-O bonds will form. Remote plasma ALD
can be used to create a seed layer.
Once the Pt ALD process started, it can be continued
with either plasma or thermal ALD at similar rates.

Conformal coating of 20 nm Pt in
75 nm by 2.5 mm trench
(AR 33 to 71 after coating)
with kind permission of
Uni Michigan and NIST

Pt ALD (thermal and radical assisted by remote plasma)

Metal precursor: MeCpPtMe3

Delivery Method: bubbled with argon
Non-metal precursor: O2 thermal or plasma

The O2 plasma significantly reduces
the nucleation delay.

The initial thermal Pt nucleation process
is pressure dependent.
Radical assisted ALD results in a
much shorter nucleation delay.

H2 plasma can reduce PtO2 to Pt and
lowers temperature range of Pt deposition.

- 0.45 Å/cycle
- 7-8 sec cycle time
- Deposition rate ~ 0.3 - 0.4 nm /min
                             ~ 18 - 24 nm /h
- Resistivity ~13 µOhm cm

with kind permission of TU Eindhoven


DOWNLOAD white paper on Pt ALD (2011)



Pt grown on textiles




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.

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


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