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Spatial distribution of carbon and native defects in large-diameter bulk grown GaAs

Conference ·
OSTI ID:5555096
Different spectroscopic techniques have been combined to measure concentrations of carbon on arsenic sites and of neutral EL2. Utilizing the recently found dependence of the high resolution local vibrational mode spectrum on the charge state of the carbon acceptors we have been able to separately determine concentrations of neutral and ionized carbon after EL2 has been optically quenched. The concentration of ionized carbon shows a very distinct W-shaped variation across the wafer whereas the total carbon concentration is close to constant. The variations are caused by the nonuniform distribution of donors which are shallower than EL2. The account for the commonly observed variations of the near infrared absorption. Radiotracer experiments with GaAs crystals intentionally doped with /sup 14/C showed that carbon is very homogeneously distributed in GaAs grown by horizontal Bridgman method. No correlation between the distribution of carbon and dislocations has been found. 17 refs., 5 figs.
Research Organization:
Lawrence Berkeley Lab., CA (USA)
DOE Contract Number:
AC03-76SF00098
OSTI ID:
5555096
Report Number(s):
LBL-22751; CONF-8704248-2; ON: DE88003870
Country of Publication:
United States
Language:
English