Ti-Star, (pentamethylcyclopentadienyl)trimethoxy-titanium, CpMe5 Ti(OMe)
with 1,2-dimethoxyethane adduct Sr(iPr3Cp)2 DME
non metal precursor: O radicals
controlled via bubbling
dose control by fast pulse ALD valve
deposition temperature: 150° - 350° C
The performance of Pt/STO/Pt capacitors could be varied between
high-k applications (CET ~ 0.7 nm) and integrated capacitor applications
(low quadratic voltage coefficient of capacitance alfa à 0 ppm
choosing tailored compositions and microstructures of the plasma-assisted
ALD STO films.
Crystal structure of SrTiO
Red: oxygen, blue: titanium,
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
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.
low temperature ALD down to 25° C
is enabled by the use of O radicals;
this is not practical using thermal
valve between remote ICP source
spectroscopic ellipsometry optional