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

Paper SS1+EM-TuM3
Increase of Electrical Conductivity in p-GaN by Immersion in H@sub2@O@sub2@ Solution*

Tuesday, October 26, 1999, 9:00 am, Room 606

Session: Nitrides and Compound Semiconductors
Presenter: B. Liu, University of Florida
Authors: B. Liu, University of Florida
M.H. Ahonen, University of Florida
P.H. Holloway, University of Florida
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Immersion in a peroxide solution was found to increase electrical conductivity in p-GaN films. Auger electron spectroscopy (AES), current-voltage and Hall measurements were used for characterization. All samples in this study were grown on the c-plane of sapphire substrates by metallorganic vapor phase epitaxy (MOVPE) with a carrier concentration of 1.1x10@super 17@ cm@super -3@. The samples were first cleaned in boiling aqua regia (3HCl+3HNO@sub 3@) for 10min, rinsed in DI water, and blown dry with N@sub 2@. Metal contacts (10nmNi/100nmTi/100nmAu) were deposited with an electron beam evaporator (~10@super -6@ Torr). After metal deposition, samples were immersed in a H@sub 2@O@sub 2@ solution (1H@sub 2@O@sub 2@ : 5H@sub 2@O or 1H@sub 2@O@sub 2@ : 1H@sub 2@O, in volume) for different time (30sec to 300sec). This was followed by DI water rinse and N@sub 2@ blowing dry. Surface composition analysis using AES showed differences in N concentration versus treatments with the highest increase of N (5.67at%) found after immersion in 1H@sub 2@O@sub 2@ : 1H@sub 2@O for 300sec. Corresponding to this increase in N, improved electrical conductivity was confirmed by current-voltage data. The highest (a factor of two) increase of conductivity was measured for the sample with the highest increase of N concentration. No increase of carrier concentration was found in these samples with Hall measurement. The increase of N atoms at the sample surface and improvement of electrical conductivity will be discussed based on the chemical reaction of H@sub 2@O@sub 2@ with GaN and the effects of N vacancies in p-GaN. * This work is supported by EPRI and DARPA under agreement W08069-07.