Congratulations to Lawrence Berkeley National Laboratories (LBNL) who have recently published an ALD related article in Nature Communications (see link here). The article relates to work on bioelectrochemical systems. LBNL converted one of their thermal ALD systems to plasma with a Meaglow hollow cathode plasma source back in 2015, and for this paper the plasma source has been used to produce silicon oxide layers at 80 degrees C. A second paper published in ACS Nano (see link here) also reports on silicon oxide produced with the Meaglow plasma source.
A number of such conversions have been carried out by Meaglow. See http://www.meaglow.com/hollow-cathode-sources-for-thermal-ald/
Other publications by our customers can be viewed at http://www.meaglow.com/publications/
Recognising that our customers would like more information, Meaglow has released a new company white paper describing the operation and advantages of our hollow cathode plasma sources. Our hollow cathode designs are well known for greatly reduced oxygen contamination issues, but there are other advantages, such as low plasma damage, scalability, high radial flux and high electron density. Our company white papers are available here. The new white paper can also be viewed at this link: Hollow Cathode Plasma Sources for Plasma Enhanced ALD and PECVD.
Mr James Thorn, a happy customer, after the installation of a Meaglow hollow cathode plasma source on one of the group’s thermal ALD systems at Boston College.
In December of 2017, Dr Necmi Biyikli of the University of Connecticut received a new hollow cathode plasma source for his Okyay Tech thermal ALD. The source has it’s own sample entry port, and ellipsometer ports. Additionally, this is one of Meaglow’s new large area sources, capable of very high electron density of 10^13 cm^-3 over the full deposition area. The system has been working well!
The answer is, yes.
Of course hidden away in someone’s lab, somewhere, there might be something comparable, but that wouldn’t be ‘available’. Certainly there’s nothing else like this that we’re aware of. So let’s have a look at what makes Meaglow’s latest hollow cathode design so special.
The plasma source shown was developed for the conversion of OkyayTech’s thermal ALD systems. This model is for 4″ wafers, it has a separate loading port for samples; doesn’t need cooling water, and it really doesn’t care about getting deposits on the cathode.
Using nitrogen gas we’ve measured the electron density to greater than 10^13 cm^-3 at 300 watts of RF power. That’s a formidable value for any plasma source, about an order of magnitude higher than other commonly available 300 watt products, but here’s the thing, that plasma density is being generated over an area equal to the substrate.
Other solutions generate high density plasma in a small volume and then disperse it to a larger area. Not so the new Meaglow source, it has an extremely high plasma density over the full substrate area. This design has already been successfully implemented in 4″ and 8″ systems, and there are plans to go to 12″.
“This is the way that ALD should be done,” says Meaglow’s Chief Scientist, Dr Scott Butcher. “We’re developing plasma sources specifically for ALD, not trying to adapt old legacy sources that are less than optimum for the technique.”
Many of our hollow cathode customers had started asking: ‘What’s the best new system to buy if I want to convert to hollow cathode?’ But recently a past customer came and asked us to build a full ALD/ALE system for him. The system was commissioned in June and July and is for 8″ wafers. It is UHV compatible and includes an 8″ diameter hollow cathode source, compatible with chlorine plasma operation.
Meaglow has begun building a second smaller 4″ system, though this one will see a substantial increase in plasma power. Meaglow has published and has patent applications for methods that could allow some real leaps forward in ALD and other plasma technology.
Six new journal publications from three groups can be found on our website, with links to the publishers for downloading the articles. See http://www.meaglow.com/publications/ The titles are::
“Low-temperature self-limiting atomic layer deposition of wurtzite InN on Si(100)”
“Comparison of trimethylgallium and triethylgallium as “Ga” source materials for the
growth of ultrathin GaN films on Si (100) substrates via hollow-cathode plasma assisted
atomic layer deposition”
“Substrate temperature influence on the properties of GaN thin films grown by hollow cathode plasma-assisted atomic layer deposition”
“Low-temperature sequential pulsed chemical vapor deposition of ternary BxGa1-xN
and BxIn1-xN thin film alloys”
“Self-Catalytic Growth of InN Nanowires”
“Optoelectronic and structural properties of InGaN grown by Migration-Enhanced, Plasma-Assisted MOCVD”
A big thanks to our customers and collaborators for being so productive, we’re glad our hollow cathode plasma sources have given you that technology edge!
Meaglow’s Chief Scientist, Dr Butcher, and our Korean agents from Paultec will be there.
Meaglow will have table 28 of the exhibits. We are extremely pleased that representatives of our Korean agency, Paultec, will also be present, including Mr. Dong-Hyun Kim. A series 50 plasma source, one of our most popular sources, will be brought to the exhibition. Come and talk to us about reducing oxygen levels in nitride films. We hope to see you in Dublin on the 24th-27th of July.
The NASA Jet Propulsion Laboratory (JPL) have converted one of their ALD systems to a custom made Meaglow hollow cathode plasma source. This is an 8″ diametre plasma source, one of our biggest in recent years. The source was delivered early this year and has apparently been running extremely well. Results may be presented later this year.