[solid with low vapour pressure]
plasma gas: O2
(does not react thermally with H2O)
dose control by fast pulse ALD valve
bubbled at 190° C
deposition temperature: 250° - 300° C
0.18 A/ cycle (saturated dose at 300° C)
refractive index 1.72 - 1.74
valve between remote ICP source
spectroscopic ellipsometry optional
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
efficient plasma preclean/ conditioning of the
substrates, lead to cleaner films and lower
the deposition temperature.
In Oxford systems it is possible to
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.
Self limiting behaviour and linear growth
regime with nucleation delay, Thickness
measured by spectroscopic ellipsometry