Plasma Technology  


AES of a 65 nm ALD film


X-Ray Diffraction (XRD) analysis shows a
small peak attributable to GaN [0002].

 

GaN ALD (radical assisted by remote plasma)


metal precursors:
triethyl gallium (TEGa)

non metal precursor: N2/H2 remote plasma

temperature controlled vapour draw

dose control by fast pulse ALD valve

deposition temperature: 150° - 350° C

A long plasma exposure is necessary to achieve a low oxygen
content and therefore a high refractive index. Although the
process saturates with a 5 second plasma, longer times
are needed to drive off the impurities to reach the impurity
levels quoted herein.

uniformity: < ± 0.5 - 2 %
(depending on substrate size)

C < 3% , O < 3%

refractive index 2.27

Up to 1.75 A/ min, > 10 nm/ hr (for 100 mm wafer)
(faster for smaller substrates)


 

 

 

 

 

 

 

 

 

 

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.

 


FlexAl

 


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

 

 

OpAl

 

 

 

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