Site-controlled and size-homogeneous Ge islands on prepatterned Si (001) substrates

Abstract

We report on a combination of lithography and self-assembly techniques which results in long-range two-dimensionally ordered Ge islands. Island lattices with perpendicular but also with obliquely oriented unit vectors were realized. Quantitative analysis of the island topographies demonstrates that the size dispersion of these islands is smaller than that found on flat substrates. Furthermore, island formation on the patterned substrates is observed for a smaller amount of Ge deposition. However, with further Ge deposition an increasing amount is incorporated into the sidewalls.

SiGe growth on patterned Si(001) substrates: Surface evolution and evidence of modified island coarsening

“…A similar evolution has already been reported during Si buffer growth on holographically patterned Si͑001͒. 11 When the Si buffer layer is increased to 72 nm, the pit morphology is similar, except for a larger pit diameter. An AFM scan of such a pit is shown in Fig.…”

“…6 Long range ordering in two dimensions using either selective epitaxial growth through oxide masks 7 or direct growth on prepatterned substrates [8][9][10] was successfully demonstrated and excellent size homogeneities were reported. 11 However, the island formation and subsequent evolution on pit-patterned Si͑001͒ substrates are still not completely understood. While the initial stages of the twodimensional ͑2D͒ to 3D transition during Ge deposition on a pit-patterned Si͑001͒ surface have been recently studied, 12 a detailed investigation of the morphological changes occurring during island growth is still lacking.…”

Photodetection in Hybrid Single-Layer Graphene/Fully Coherent Germanium Island Nanostructures Selectively Grown on Silicon Nanotip Patterns

“…The latter four features are of particular importance if NHE is benchmarked against other deposition techniques used to achieve Ge nano-islands such as the Stranski-Krastanov growth of Ge on planar Si substrates, which leads to randomly distributed, highly intermixed, size inhomogeneous self-assembled islands [12][13] . Pit-patterned Si substrates have been utilized to improve ordering and size uniformity [14][15][16][17][18] but with this approach Si-Ge intermixing is not prevented owing to the rather high process temperature required to achieve selectivity and high crystal quality 15,17 .…”

Delayed Plastic Relaxation on Patterned Si Substrates: Coherent SiGe Pyramids with Dominant{111}Facets

“…Such f111g pyramids are the result of a shape transition from domes, accompanied by a substantial increase of the a=r. Molecular dynamics (MD) simulations and elasticity-theory calculations are used to explain the role played by the substrate pattern in altering the strain distribution and favoring coherence at high a=r.Patterned Si(001) substrates with two-dimensionally (2D) periodic pits along two orthogonal h110i directions were obtained by holographic lithography and reactive ion etching [16,17]. To create a well-defined starting surface, a 130 nm thick Si buffer layer was grown with 0:05 nm=s while ramping the temperature from 450 C to 600 C. On sample A only the Si buffer was deposited, whereas samples B and C received in addition 5 and 7 monolayers (ML) of Ge, respectively, which were deposited at 620 C with 0:005 nm=s and 7 s growth interruption after each ML [16].…”