Effect of growth rate on the spatial distributions of dome-shaped Ge islands on Si(001)

Abstract

Ge/Si͑001͒ layers are grown by gas-source molecular beam epitaxy at 600°C to probe island self-ordering phenomena. We vary the Ge growth rate by a factor of 40, 1.2-47 monolayers ͑ML͒ min Ϫ1 , and adjust the Ge coverage, 5.9-8.9 ML, to produce films consisting primarily of dome-shaped Ge islands. Measurements of the radial and nearest-neighbor distributions are compared to calculated distributions for random arrangements of circular islands. At low growth rates, island formation is inhibited at small separation. At high growth rates, the angular distributions of nearest-neighbor islands show pronounced island ordering along ͗100͘ directions.

Morphological evolution of self-assembled SiGe islands based on a mixed-phase pre-SiGe island layer grown by ion beam sputtering deposition

“…The diameters of the islands are smaller than that grown by depositing SiGe layer on Si observed above. Note that the critical thickness (1.8 nm) of the islands fabricated by IBSD technique is larger than that fabricated by MBE and CVD techniques [24,25,26]. Our previous results indicated that the μc-Si buffer layer and the higher kinetic energy of the sputtered Si and Ge atoms may explain this phenomenon [10,12].…”

Buffer layer-assisted growth of Ge nanoclusters on Si

“…9, reveal sublinear (~0.50) power exponents for both P1 and P2 bands. Sublinear power exponentfs with a power exponent of~0.78 have previously been attributed to a type-II band alignment with a limited density of localized states for excitons [4,15]. An increase of localization of the radiative centers would lead to a smaller power exponent.…”

“…As already mentioned foremost, without the presence of a Xe buffer layer, Ge growth on Si(100) is well known to form SK clusters [13][14][15] in the absence of a Xe buffer layer. Strain-driven SK growth proceeds in two steps.…”

DOE A9024 Final Report Functional and Nanoscale Materials Systems: Frontier Programs of Science at the Frederick Seitz Materials Research Laboratory

“…To explore the possibilities, Cahill and Greene employ laser processing to modify surfaces and films [53,54,55,56] . A recent experiment on the controlled pulsed illumination of thin thermally-grown oxide layers on Si has shed light on the process of delamination by thermal stress due to differential expansion [57] .…”