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The benefits of ALD
- Because the ALD process deposits precisely one atomic layer in each cycle, complete control over the deposition process is obtained at the nanometre scale
- Conformal coating can be achieved even in high aspect ratio and complex structures
- Pin-hole and particle free deposition is achieved
A very wide variety of materials is possible with ALD:
Oxides, including HfO2, HfSiO, Al2O3, Ta2O5, TiO2, La2O3, SiO2, ZnO
Nitrides, including TiN, TaN, AlN, SiNx, HfN
Metals, including Ru, Cu, W, Mo
The benefits of remote plasma ALD
In addition to the benefits of thermal ALD, remote plasma allows for a wider choice of precursor chemistry with enhanced film quality:
- Plasma enables low-temperature ALD processes and the remote source maintains low plasma damage
- Effective metal chemistry through use of hydrogen plasma rather than complex thermal precursors
- Eliminates the need for water as a precursor, reducing purge times between ALD cycles - especially for low temperatures.
- Higher quality films through improved removal of impurities, leading to lower resistivity, higher density, etc.
- Ability to control stoichiometry
- Plasma surface treatment
- Plasma cleaning of chamber is possible for some materials
ALD Applications
Including;
- High-k gate oxides
- Storage capacitor dielectrics
- Pinhole-free passivation layers for OLEDs
and polymers
- Passivation of crystal silicon solar cells
- High aspect ratio diffusion barriers for Cu interconnects
- Adhesion layers
- Organic semiconductors
- Highly conformal coatings for microfluidic and MEMS applications
- Other nanotechnology and nano-electronic applications
- Coating of nanoporous structures
- Fuel cells, e.g. single metal coating for catalyst layers
- Bio MEMS
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The ALD cycle
1. TMA dose
2. TMA purge
3. O2 plasma
4. Short post O2 plasma purge
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