Structural, electronic, and luminescence investigation of strain‐relaxation induced electrical conductivity type conversion in GeSi/Si heterostructures

Autor:	Eugene A. Fitzgerald, Steven A. Ringel, J. Michel, P. N. Grillot
Rok vydání:	1996
Předmět:	Photoluminescence Materials science Spreading resistance profiling Electrical resistivity and conductivity Electron beam-induced current Analytical chemistry General Physics and Astronomy Heterojunction Conductivity Dislocation Crystallographic defect
Zdroj:	Journal of Applied Physics. 80:2823-2832
ISSN:	1089-7550 0021-8979
DOI:	10.1063/1.363200
Popis:	Strain‐relaxed, compositionally graded Ge0.3Si0.7/Si heterostructures grown by ultrahigh vacuum chemical vapor deposition at 650 °C are shown to display a consistent change from p‐type to n‐type conductivity as a function of rapid thermal annealing (RTA) temperature in the range 700–850 °C. Cross‐sectional transmission electron microscopy, spreading resistance, and electron beam induced current (EBIC) studies eliminate the dislocations themselves as a possible source of this type conversion, by demonstrating that the spatially invariant hole concentration of 2×1014 cm−3 is not correlated to the dislocation density, which decreases from ∼108 cm−2 in the graded region to 7×105 cm−2 in the 30% Ge cap. To identify the source of type conversion, a systematic investigation was performed on 650 °C as‐grown and annealed samples with deep‐level transient spectroscopy (DLTS), photoluminescence (PL) and capacitance–temperature (C–T) measurements. DLTS measurements on as‐grown samples reveal a complex spectrum of dee...
Databáze:	OpenAIRE
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