ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
We have used a combination of electron-beam-induced current (EBIC), etching, and optical measurements to show dramatic differences between the minority-carrier transport properties and defect structures in GaAs wafers from two different vendors. We found that the EBIC defects correspond to the traditional ones found with molten KOH etching and optical inspection. However, the EBIC micrographs give a great deal of additional information. The EBIC patterns from the first vendor's wafer showed diagonal striations and point defects that made the EBIC go to zero and were interconnected by wormlike lines. The second vendor's wafers showed EBIC point defects that only suppressed the response by 20% and gettered the surrounding material so that it had higher EBIC response. However, this second vendor's wafer had about a 15% overall lower EBIC response and a much higher density of surface polish defects identified by reflected light. Etching data showed that EBIC defects are bulk material properties and that electrochemical etching with a KOH electrolyte allows the wormlike defects to be seen optically in a Nomarski equipped microscope. Examination of epilayers showed that the wafer defects did not propagate up into a 4-μm-thick layer grown by vacuum chemical epitaxy or a 1.5-μm-thick layer grown by molecular-beam epitaxy.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.339098
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