Inductively coupled plasma (ICP) sources were developed for use in the semiconductor industry decades ago, at a time when mainly silicon oxide and silicon nitride were being deposited by plasma sources. Today new materials have more exacting demands, especially for plasma assisted atomic layer deposition. The older sources have problems with oxygen contamination from sputtered dielectric windows (typically quartz or alumina). However, apart from that, the idea of using a high density power source generated in a small area tube and then diluting the activated species over a larger deposition area may be an idea that’s had its day. Small area sources are used so that back flow of metalorganic into the dielectric tube is minimised, since such deposition can block RF transmission to the plasma gas, and potentially cause damage to the dielectric liner.
Enter the hollow cathode plasma source, free of oxygen contamination problems (see our company white paper on this issue) and able to cope with both metallic and insulating deposition on the cathode. Now a high density plasma source can be made to the same dimensions as a substrate – there is no need to dilute the plasma species over a larger area. The plasma source can also be brought closer in. The OkyayTech P100 (shown above) utilizes Meaglow’s large area high density hollow cathode source. Below is a useful table showing some results from the University of Connecticut group of Dr. Necmi Biyikli (pictured above). These demonstrate the advantage of breaking away from the old ICP plasma delivery paradigm.
Check out the Meaglow website at www.meaglow.com or contact us at firstname.lastname@example.org or +1 807 252 4391, for more information on our plasma products. Meaglow and OkyayTech collaborate to build ALD tools with new generation plasma sources. You can check out the OkyayTech website at www.okyaytech.com or contact them at email@example.com or +1 818 318 9616, for more information on their ALD and ALE tools.