AVS 46th International Symposium
    Surface Science Division Tuesday Sessions
       Session SS1+EM-TuM

Paper SS1+EM-TuM6
The Reaction of Oxygen with GaN(0001)

Tuesday, October 26, 1999, 10:00 am, Room 606

Session: Nitrides and Compound Semiconductors
Presenter: B.D. Thoms, Georgia State University
Authors: B.D. Thoms, Georgia State University
V.J. Bellitto, Georgia State University
Y. Yang, Georgia State University
D.D. Koleske, Naval Research Laboratory
A.E. Wickenden, Naval Research Laboratory
R.L. Henry, Naval Research Laboratory
Correspondent: Click to Email
In addition to optoelectronic applications, Group III Nitrides also exhibit properties appropriate for their use in high power and high temperature transistors. Oxidation of the surface influences several aspects of device fabrication including surface passivation and the production of metal contacts. We have characterized the reaction of oxygen with MOCVD-grown GaN(0001) using low energy electron diffraction (LEED), Auger electron spectroscopy (AES), energy loss spectroscopy (ELS), high resolution electron energy loss spectroscopy (HREELS), and temperature programmed desorption (TPD). AES of GaN(0001) following exposure to O2 at room temperature results in an increased O(KLL) Auger intensity which saturates after approximately 200 L. AES following heating shows that oxygen is present to temperatures of 900 C. No surface reconstruction is observed by LEED, but rather a reduction in contrast between diffraction spots and background with increasing oxygen exposure. The reaction with oxygen produces a reduction in the ELS intensity at loss energies of 3.5 and 6 eV. A similar reduction is observed after exposure to atomic hydrogen, consistent with the reaction of both oxygen and hydrogen with surface dangling bonds. Oxygen exposure also produces an increase in ELS intensity at 10 eV. In HREEL spectra acquired following oxygen exposures up to 200 L, no adsorbate vibrational features are resolved from Fuchs-Kliewer phonon losses at integer multiples of 700 cm-1. These data are consistent with the chemisorption of oxygen on Ga sites.