Dresden 2003 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 14: Poster I

HL 14.10: Poster

Montag, 24. März 2003, 17:00–19:30, HSZ/P2

Electrical characterization of defect zones surrounding dislocations in semi-insulating GaAs. — •Andrei Sidelnicov, Winfried Siegel, and Günter Kühnel — Andrei.Sidelnicov@physik.tu-freiberg.de

Mesoscopic electrical non-uniformities existing in undoped bulk-grown semi-insulating GaAs (SI-GaAs) crystals correlate with distribution pattern of dislocations. Direct measurements of local resistivity variation in micro-environment of single dislocations were performed by means of improved point contact current topography (PCCT) technique with high local resolution ( < 5 µ m). In SI-GaAs wafers grown by different methods (LEC, VGF and VCz) nearly the same diameter for the defect zones with changed electrical properties was found. Moreover, resistivity patterns of dislocations’ arrangements (groups, cellular structures) were investigated and related to the elementary defect zones of single dislocations. Finally mechanisms of defect atmosphere formation during growing and subsequent annealing processes will be discussed.