Researchers at the California Institute of Technology (Caltech) have joined a growing number of institutes that have upgraded their plasma assisted ALD system with a hollow cathode plasma source. Meaglow’s plasma sources are well known for improving nitride layers by lowering oxygen content.
One such upgrade enabled low temperature GaN thin film transistors to be deposited at 200 degrees C (see the related Applied Physics Letter). While more recent work has allowed the demonstration of superior silicon nitride layers grown for device purposes (see our earlier article).
Meaglow is committed to enabling the next generation of materials development by providing deposition solutions that meet the stringent requirements of today’s researchers. See our product lines at www.meaglow.com.
Dr Eran Edri of Ben-Gurion University of the Negev has the first Meaglow hollow cathode source in Israel. Eran was formally from Lawrence Berkeley National Laboratories in the US, where he used one of our plasma sources there for the near room temperature ALD of silicon oxide. Several of Eran’s papers are listed on our website at our journal publication page.
Initial tests with the plasma source have gone well. A commercial ALD system was converted to use with the hollow cathode, the second of this particular brand. Meaglow has converted many of the popular ALD brands to use with its sources, including thermal systems. Among other advantages, the Meaglow sources offer lower oxygen contamination for nitride films. See our brochures page here.
While ALD2018 was going on in Incheon, South Korea, the first Meaglow hollow cathode plasma source in South Korea was being installed at Hanyang University in Ansan.
This is one of a number of firsts for Meaglow this year, we’ve also had our first sale to Israel (to Ben-Gurion University of the Negev), our first sale to Gerrmany (to Otto-von-Guericke University, Magdeburg) and our first sale to the United Kingdom (to the University of Liverpool). All of these sales have been for Meaglow’s popular Series 50 Plasma Source, which is used by many of our customers to upgrade from ICP to hollow cathode plasma operation.
Contact us at email@example.com to learn more about the benefits of Meaglow’s plasma technology.
In a recent IEEE advance publication, staff at UT Dallas have achieved high density (2.9 g/cubic cm) crystalline silicon nitride for SiN/GaN devices using hollow cathode plasma enhanced ALD. These films were deposited at 300 degrees C, but have other features akin to silicon nitride grown at much higher temperatures using LPCVD, including a low etch rate in 100:1 HF solution of 0.8 nm/min and excellent electrical device properties.
In a related paper the same UT Dallas group were able to measure low oxygen content for their silicon nitride grown with a Meaglow hollow cathode plasma source, and exceptionally low leakage currents of 1-2 nA/cm square, at 2 MV/cm with a breakdown field of about 12 MV/cm.
Says Dr. Antonio Lucero of UT Dallas, “The Meaglow hollow cathode plasma system has allowed our group to deposit SiN films using a variety of precursors. We consistently obtain excellent film properties and have observed a number of unique characteristics due to the hollow cathode plasma source.”
Meaglow’s hollow cathode plasma sources are well known for reducing the oxygen contamination known to occur with other plasma sources (see company white paper). Contact us at firstname.lastname@example.org to talk about upgrading your plasma source to a hollow cathode.
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.