C-V - and DLTS-Investigations of Pyramid-Shaped Ge Quantum Dots Embedded in N-Type Silicon

Abstract:

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We investigate self-assembled pyramid-shaped Ge Quantum Dots (QDs) with lateral dimensions of 15 nm, and heights of 2.5-3 nm. These Ge QDs were grown by Molecular Beam Epitaxy (MBE) on n-type Si(100) substrates using the Sb-mediated growth mode. The resistivity of the substrates was about 5 Ωcm. The Si buffer layer below the QDs and the Si capping layer above them were doped up to 1018 cm-3 by Sb. Cross-section transmission electron microscopy shows the QDs and the Sb delta-doped layers. Using standard photolithographic techniques, a 0.3 mm2 Au Schottky contact was applied to the epilayer, while an Ohmic contact was formed on the back side of the substrate. Plotting C-2 vs. V plot reveals the nominal doping of 1018 cm-3. DLTS studies revealed two levels with fitted activation energies of 49 meV and 360-390 meV. They are related to the Sb doping and the Pb interface states, respectively. The simulation suggests a deep level with a volumetric concentration of 2.55×1015 cm-3. Multiplying this value by the thickness of the depletion region obtained from the CV measurements, we find that the deep level capture about 5.8×109 electrons per cm2.

Info:

Periodical:

Solid State Phenomena (Volumes 178-179)

Edited by:

W. Jantsch and F. Schäffler

Pages:

72-75

DOI:

10.4028/www.scientific.net/SSP.178-179.72

Citation:

V. T. Rangel-Kuoppa et al., "C-V - and DLTS-Investigations of Pyramid-Shaped Ge Quantum Dots Embedded in N-Type Silicon", Solid State Phenomena, Vols. 178-179, pp. 72-75, 2011

Online since:

August 2011

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$35.00

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