Plasma Technology  

thickness and refractive index (measured
by spectroscopic ellipsometrry) vs cycle number

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


SiNx ALD (radical assisted by remote plasma)

precursor: 3DMAS*
N2/ H2 plasma

vapour draw at 40° C

dose control by fast pulse ALD valve

deposition temperature: 350° C

near stochiometric film
refractive index up to 1.95

0.35 A/ cycle (saturated dose at 350° C)

O content < 3 %

BHF wet etch rate < 8 nm/ min

* We currently use another precurosr
for further improvements.


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.

substrate plasma preclean
plasma cleaning of the chamber
(SF6, typ 1 hour cleaning per month
of operation)


AES shows Si3N3.4 with < 3% O in the bulk

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