Onset of vertical threading dislocations in Si1−xGex/Si (001) at a critical Ge concentration


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Date

2013-11-18

Publication Type

Journal Article

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Abstract

We show that the Ge concentration in Si1−xGex alloys grown under strong out-of-equilibrium conditions determines the character of the population of threading dislocations (TDs). Above a critical value x ∼ 0.25 vertical TDs dominate over the common slanted ones. This is demonstrated by exploiting a statistically relevant analysis of TD orientation in micrometer-sized Si1−xGex crystals, deposited on deeply patterned Si(001) substrates. Experiments involving an abrupt change of composition in the middle of the crystals clarify the role of misfit-strain versus chemical composition in favoring the vertical orientation of TDs. A scheme invoking vacancy-mediated climb mechanism is proposed to rationalize the observed behavior.

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published

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Volume

1 (5)

Pages / Article No.

52109

Publisher

American Institute of Physics

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03569 - Batlogg, Bertram (emeritus) check_circle

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