RF Atom Source for atomic oxygen
and atomic nitrogen
Neutral, atomic
species have been shown to be highly beneficial in the growth of
high-quality compound materials. Molecular gases such as oxygen
or nitrogen are many orders of magnitude less reactive than if
dissociated into atomic form. Consequently, oxide formation using
molecular oxygen commonly requires highly elevated temperatures
and/or extended oxidation periods, while molecular nitrogen shows
negligible reactivity for most materials. Using dissociated
species increases the reactivity by many orders of magnitude and
therefore allows oxides or nitrides to be grown at low pressure
and at reasonable substrate temperatures. However, ionic species
generated in plasma processes tend to be energetic, and will
create point defects on impact with the growing film, rendering
many films useless for their intended purpose. Atomic species, on
the other hand, carry negligible kinetic energy and therefore allow
rapid film growth without generating defects.
RF atom sources
have been used with great success in many semiconductor
film-growth applications, such as GaN, GaInNAs, ultra-thin Al2O3,
high-K dielectrics and are being employed in a range of other
applications such as data storage, catalytic films, and surface
cleaning with atomic hydrogen.
The discharge zone
is manufactured from high-quality materials ensuring minimal
contamination of the beam. The source incorporates a zero-ion
current configuration as standard and can be fitted with a unique
beam-thermaliser to reduce the energy of the small fraction of
energetic neutrals which commonly emerge from all plasma-based atom
sources.
The end-user can
define the optimum gas flow by selecting from a range of different
end-plates. These plates can be further customized to give maximum
uniformity for a given sample size, distance and angle to the source.
