Real-time monitoring of low-temperature hydrogen plasma passivation of GaAs
By monitoring photoluminescence (PL) in real time and in situ, hydrogen plasma operating conditions have been optimized for surface passivation of native-oxide-contaminated GaAs. PL enhancement is critically dependent on exposure time and pressure because of competition between plasma passivation and damage. Optimal exposure time and pressure are inversely related; thus, previous reports of ineffective passivation at room temperature result from overexposure at low pressure. Plasma treatment is effective in removing As to leave a Ga-rich oxide; removal of excess As increases the photoluminescence yield as the corresponding near-midgap-state density is reduced. Passivation is stable for more than a month. These results demonstrate the power of real time monitoring for optimizing plasma processing of optoelectronic materials.
Additional Information© 1990 American Institute of Physics. Received 26 January 1990; accepted for publication 27 March 1990. We are grateful to W. C. Dautremont-Smith, T. K. Hayes, and Y. H. Lee for helpful suggestions and stimulating discussions and to G. R. Scheller and F. Ren for experimental assistance. We are also grateful to T. Harris and M. Lamont-Schnoes for examining the low-temperature PL spectra of both passivated and unpassivated samples.
Published - GOTjap90.pdf