AVS 45th International Symposium
    Selected Energy Epitaxy Topical Conference Wednesday Sessions
       Session SE-WeA

Paper SE-WeA7
Inexpensive Corona Discharge Source for the Growth of III-N Semiconductors

Wednesday, November 4, 1998, 4:00 pm, Room 327

Session: Novel Sources for Selected Energy Growth
Presenter: D.C. Jordan, Arizona State University
Authors: D.C. Jordan, Arizona State University
C.T. Burns, Arizona State University
R.B. Doak, Arizona State University
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The III-N nitrides AlN, GaN and InN are under intense study due to their wide bandgap properties. It is thought that the ideal nitrogen species for GaN growth may be the metastable A@super 3@@SIGMA@@super +@@sub u@ state of molecular nitrogen@footnote 1@. We have developed a low cost supersonic free-jet corona discharge source that produces exclusively this nitrogen species. The source consists of a quartz tube drawn to an orifice diameter in the range of 100-250 µm enclosing a tungsten or rhenium wire. A high voltage ranging between 2-2.5 kV at 5-9 mA is applied to that wire, resulting in a readily discernible bright plume at the tip of the nozzle. A custom-made refractory graphite skimmer then extracts a beam of activated species as the free-jet expands into vacuum. The beam transits a differentially pumped section then enters the deposition chamber where controlled growth can take place under molecular beam epitaxy (MBE) conditions. We have performed optical spectroscopy at several different locations downstream of the nozzle for different tip polarity and different argon/nitrogen gas mixtures, characterizing the expansion as it unfolds. Overall nitrogen intensities range from the 5x10@super 17@-2x10@super 18@ molecules/sr/s. Our calculations indicate that an appreciable percentage (ca.10%) of the nitrogen molecules is in the desired metastable A@super 3@@SIGMA@@super +@@sub u@ state. Growth studies of AlN on Si(100) are currently under way. The low cost, the ease of operation and the ability to produce only a single excited species are in stark contrast to the broad spectrum of different species of any other commercially available plasma source, making the corona discharge source attractive for a broad range of future applications. Supported by ONR grant # N00014-95-1-0122 & N00014-96-1-0962 @FootnoteText@ @footnote 1@ R.P.Muller, B.L.Tsai and W.A.Goddard III, SEE-3 Workshop, Tempe 1998