Evaluation of the diffusion length of minority carriers in bulk GaAs

https://doi.org/10.1016/0169-4332(91)90223-7Get rights and content

Abstract

The diffusion length of minority charge carriers has been investigated in LEC GaAs, silicon-doped with doping density ND - NA ranging from 1016 to 1018 cm-3, by surface photovoltage (SPV) and electron-beam-induced current (EBIC) of scanning electron microscopy (SEM) measurements. Au Schottky diodes have been evaporated along the diameter of wafers cut from different doping density ingots to determine the variation of minority carrier diffusion length with both the radial position on the slice and the carrier concentration. The diffusion length values obtained by optical and electron excitation enhance systematic differences, which can be explained by the different surface recombination weight in the carrier generation volume and by the injection level, too. In all the examined samples an M-shaped radial variation of the diffusion length has been observed; on the other hand, the mean value of Lp increases from 0.5 to 7 μm when the doping concentration increases. The authors correlate this distribution to the electrical inhomogeneity induced by native defects and associated recombination centres. The role of the dislocations, which induce two competitive effects, i.e. an enhanced recombination probability and a precipitate condensation, is here discussed.

References (15)

  • L.J. Giling et al.

    J. Cryst. Growth

    (1986)
  • F. Berz et al.

    Solid State Electron.

    (1976)
  • M.L. Young et al.

    Semicond. Sci. Technol.

    (1988)
  • D.J. Stirland

    Inst. Phys. Conf. Ser. No. 104

  • A.G. Cullis et al.

    J. Appl. Phys.

    (1980)
  • L. Bingwen et al.

    J. Electron Mater.

    (1987)
  • B.T. Lee et al.

    J. Appl. Phys.

    (1988)
There are more references available in the full text version of this article.

Cited by (0)

View full text