Real-time, in situ monitoring of surface reactions during plasma passivation of GaAs

Eray S. Aydil, Zhen Zhou, Konstantinos P. Giapis, Yves Chabal, Jeffrey A. Gregus, Richard A. Gottscho

Research output: Contribution to journalArticlepeer-review


Real-time, in situ observations of surface chemistry during the remote plasma passivation of GaAs is reported herein. Using attenuated total reflection Fourier transform infrared spectroscopy, the relative concentrations of -As-O, -As-H, -H2O, and -CH2 bonds are measured as a function of exposure to the effluent from a microwave discharge through NH3, ND3, H2, and D2. The photoluminescence intensity (PL) from the GaAs substrate is monitored simultaneously and used qualitatively to estimate the extent of surface state reduction. It was found that, while the -CHx(x = 2,3) and -As-O concentrations are reduced rapidly, the rates at which the -As-H concentration and the PL intensity increase are relatively slow. The concentration of -H2O on the GaAs surface increases throughout the process as surface arsenic oxides and the silica reactor walls are reduced by atomic hydrogen. These observations suggest that removal of elemental As by reaction with H at the GaAs-oxide interface limits the passivation rate.

Original languageEnglish (US)
Pages (from-to)3156-3158
Number of pages3
JournalApplied Physics Letters
Issue number24
StatePublished - 1993

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)


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