A nitrogen-beam source has been developed to significantly improve the synthesis of wide-band-gap nitrides.
In experiments supported by the Department of Defense and NASA, thin nitride films have been grown by use of a unique neutralizer for atomic-beam source (NABS). The NABS is a simple device - a hollow metal cone. When the NABS is attached to a broad-beam ion source that emits dinitrogen ions, these ions become neutralized, focused, and dissociated through collisions on the inside conical surface.
Although it is extremely simple to construct, this device made it possible to grow some of the first thin films of cubic boron nitride. The NABS was subsequently used in creating buffer gallium nitride layer structures on which high-mobility thin films of gallium nitride were grown by use of an electron cyclotron resonance source.
The potential use of an ion source with a high flux of atomic neutral species from an end-Hall system could be very important to the growth of compounds of (1) nitrogen and other elements from period V and (2) elements from period III of the periodic table. The promising initial growths in the boron nitride system indicate that these materials may be better suited to ion-beam deposition methods and less sensitive to damage than when grown by conventional (non-ion-beam) deposition methods.
This work was done by J. Albert Schultz, of Ionwerks, for Marshall Space Flight Center. For further information, access the Technical Support Package (TSP) free on-line at www.techbriefs.com under the Materials category, or circle no. 154 on the TSPOrder Card in this issue to receive a copy by mail ($5 charge).