Transition from “dome” to “pyramid” shape of self-assembled GeSi islands

Self-assembled SiGe islands with uniform shape and size by controlling Si concentration in islands

“…[5,6] (annealing or exposure in SiH 4 ), Si concentration in islands increases. Increase of the total energy of pyramid islands is smaller than that of domes.…”

“…Recently, reverse shape evolution under certain situation was reported, such as annealing or exposure in SiH 4 after growth, where islands may change from domes to pyramids [6,7]. Some researchers have studied the shape evolution of Ge islands [8,9], but these works drew conclusions under special experimental conditions and cannot provide mechanisms for evolutions under different situations.…”

Effect of Si content in SiGe islands on the critical size for shape evolution

“…Abnormal shape evolution of Ge islands with phosphorus dopant was first reported by Kamins et al [6]. Recently, similar shape transitions were reported under other situations, such as annealing or exposure in SiH 4 after growth, where islands may change from domes to pyramids [7,8]. Some researchers have studied the shape evolution of pure Ge islands [9,10], but general mechanism for shape evolutions of SiGe islands was not yet clear.…”

“…[7,8] can be explained as follow. Increasing of Si content in islands is expected after processes described in both reports (annealing or exposure in SiH 4 ).…”

Effect of growth temperature on photoluminescence of Ge(Si) self-assembled islands embedded in a tensile-strained Si layer

“…The surface density of the islands increases and their sizes decrease with a decrease of T g . At the same time the average Ge content in uncapped Ge(Si)/ε-Si dome islands defined by the X-ray analysis with using of uniform strained layer approximation [15,16] increases from~70% to~82% with a decrease of T g from 700°C to 630°C. According to the AFM studies a sharp change in the islands morphology occurs in the range of T g = 600-630°C [8] -at T g ≤ 600°C the hut islands with much smaller average height than the dome islands dominate on the surface of the structures (Fig.…”