Studies of Gallium Nitride Surface
Victor Bellitto
In addition to their recent application to blue and UV LEDs and lasers,
Group III nitrides are under investigation for use in high temperature,
high-power, and high-frequency electronic devices. Hydrogen has been
reported to significantly affect growth, etching, and doping of GaN. Yet
many basic questions about the role hydrogen plays in GaN growth and processing
have not been answered. We have examined the reaction of molecular
and atomic hydrogen with GaN(0001) using low energy electron diffraction
(LEED), Auger electron spectroscopy (AES), energy loss spectroscopy (ELS),
and high resolution electron energy loss
spectroscopy (HREELS). The ELS spectrum of GaN is seen to be particularly
sensitive to exposure to atomic hydrogen, while the HREELS spectrum shows
vibrational losses which are attributed to GaH and NH stretching modes.
The ELS spectrum of atomic-hydrogen-exposed GaN is also observed
to be affected by low energy electron exposure. With repeated electron
exposure the ELS spectra appear identical to those taken with no atomic
hydrogen exposure. Further work will consist of the etching reactions
of chlorine with the GaN surface.