Growth of high quality Ge∕Si1−xGex on nano-scale patterned Si structures

Abstract

Heteroepitaxial growth of thick (∼6μm) Ge∕3μm SixGe1−x layers on nano-scale patterned Si substrates has been investigated. These nm scale structures are fabricated using interferometric lithography with reactive ion and wet-chemical etching techniques. The quality of the growth on the nanopatterned substrates was compared to growth on planar substrates. The quality of the epitaxial layers was characterized using scanning electron microscopy, transmission electron microscopy, high-resolution x-ray diffraction and etch pit density measurements. We demonstrated the nanopatterned structures produce significantly superior quality heteroepitaxial epilayers in comparison with unpatterned Si surfaces. The dislocation density of Ge epilayers on the nanopatterned Si was ∼ three orders magnitude lower than on planar Si. Growth on nanopatterned surfaces also reduced surface roughness and eliminated crosshatch patterns characterstic of planar surfaces.

High-quality heteroepitaxial Ge growth on nano-patterned Si templates using diblock copolymer patterning

“…Threading dislocation density was also lowered by one order of magnitude (to 10 6 cm À2 ) by using two-dimensional oxide pillar arrays [7]. Vanamu et al [8] demonstrated three-order reduction in the dislocation density for the Ge grown on a several hundredths nanometer-scale patterned Si substrate in comparison with the growth on a nonpatterned substrate.…”

Growth of high-quality GaAs on Ge∕Si1−xGex on nanostructured silicon substrates

“…7 Therefore, a buffer layer is necessary to integrate these two materials. 7,10- 13 We have used the graded buffer approach to integrate GaAs with Si. The most promising scheme is the linearly graded buffer layer ͑Si 1−x Ge x ͒.…”

“…By comparing TEM images in Figs. 13 Also the probability of dislocation interaction and multiplication is reduced. The Nomarski optical microscope images of the etched surfaces of the GaAs on Ge on the planar and submicrostructured samples are shown in Figs.…”