Atomic force microscopy study of the growth and annealing of Ge islands on Si(100)

Abstract

Atomic force microscopy is used to study the growth and annealing of Ge islands on Si(100) by molecular beam epitaxy. The Ge island shape, size distribution, number density, and spatial distribution under various growth conditions, such as different substrate temperatures, Ge beam fluxes, and annealing times, are investigated. By limiting the growth to a low coverage of 6 ML of Ge, we find that either a low growth temperature (*£875 K) or a high beam flux can produce films dominated by pyramids of {105} facets. Domes of higher aspect ratios only appear at high growth temperatures or after a long time of annealing at low temperatures. This indicates that in the competition between the different kinetic processes responsible for the pyramid and dome formation, the domes require a higher activation energy and grow slower. We also demonstrate that appropriate annealing at low temperature can form locally ordered arrays of pyramids with a narrow size distribution.

Ultrathin films of Ge on the Si(100)2 × 1 surface

“…For example, the transition from layers to islands formation seems to depend on the growth substrate temperature . Also the size, density, uniformity, composition, and morphology of the islands depend not only on the growth temperature but also on the annealing time, the growth rate, and the environment . Especially the growth environment can suppress the Ge‐Si intermixing, developing islands richer in Ge .…”

Molecular beam epitaxy of InN dots on nitrided sapphire

“…Growth under nitrogen-rich conditions, i.e. In/N<1, results in small pyramidal islands, whereas In/N>1 provides large pillar shaped islands [8], which suggests a possible role of indium as a surfactant [12]. To explain the effects of the III/V ratio and substrate temperature, a physical model of InN growth was proposed [11].…”

“…Using MBE or metal-organic chemical vapor deposition (MOCVD), selforganized InN nanoislands are grown on different substrates, including GaN [6][7][8][9][10][11][12] or AlN [13,14] templates on sapphire or silicon, as well as directly on Si (111) [13,15].…”

Imaging of InGaN inhomogeneities using visible apertureless near-field scanning optical microscope

“…Details of the GaN growth are also reported previously. 28 InGaN is deposited on the GaN buffer layer at a temperature of 550 °C keeping the nitrogen pressure at 2×10 -3 Pa and the RF power at 300 W. In and Ga fluxes of 1.3 nm/min and 6.7 nm/min, respectively, are supplied to the MBE chamber. After 90 min of growth, the InGaN film thickness is about 0.5 µm.…”

“…28 A GaN buffer layer is grown after the nitridation of the substrate. A Ga/N flux ratio at (or slightly above) one is used to achieve smooth GaN surfaces.…”