Versatile buffer layer architectures based on Ge1−xSnx alloys

Abstract

We describe methodologies for integration of compound semiconductors with Si via buffer layers and templates based on the GeSn system. These layers exhibit atomically flat surface morphologies, low defect densities, tunable thermal expansion coefficients, and unique ductile properties, which enable them to readily absorb differential stresses produced by mismatched overlayers. They also provide a continuous selection of lattice parameters higher than that of Ge, which allows lattice matching with technologically useful III-V compounds. Using this approach we have demonstrated growth of GaAs, GeSiSn, and pure Ge layers at low temperatures on Si(100). These materials display extremely high-quality structural, morphological, and optical properties opening the possibility of versatile integration schemes directly on silicon.

Vacancy-oxygen defects in p-type Si1−xGex

“…The increase of FWHM has been attributed to additional contributions to the shape of the VO band originating from (VO-Ge) structures with the Ge atoms in adjustment positions to a VO core. In particular, Lorenztian profiling 17,23,26 of the band has attributed two bands at ~ 834 and 839 cm -1 to a (VO-Ge) 1 and (VO-Ge) 2 structures with the Ge atom in the first and second neighbour position in relation with VO, correspondingly. On the other hand, a reduction in the amplitude of the VO band was also verified 21,22,27 by deep level transient spectroscopy (DLTS) and Laplace DLTS spectroscopy studies.…”

“…As a result, the binding energy of self-interstitials in the large self-interstitial clusters 30 As we succinctly mentioned in the results section the shape of the VO 2 band is disturbed and Lorentzian profiling has shown the existence of two additional contributed bands at 892 and 896 cm -1 .These bands are similar to those observed in our previous work 23 in n-type Si 1-x Ge x . They were attributed to (VO 2 -Ge) 1 and (VO 2 -Ge) 2 defects originating from structures with the Ge atoms in the first and the second neighbour position in relation with a VO 2 core.…”

“…[1][2][3][4][5] An enabling factor is the advent of high dielectric constant (high-k) dielectrics that allow the departure from the prerequisite to use native oxides such as SiO 2 in Si-based devices. [6][7][8] Si 1-x Ge x is a random alloy with the diamond structure that has one lattice site that can be occupied by either Si or Ge.…”

Defect interactions in Sn1−xGex random alloys

“…Sn 1−x Ge x alloys possess advantageous optical properties and offers a range of strain options and can therefore be used as buffer layers to lattice match Si or Ge substrates with most III-V and II-VI technologically relevant compounds. 1,3 Although the structure and defect processes in diamondtype random alloys such as Si 1−x Ge x have received considerable attention, the structure of Sn 1−x Ge x has not, so far, been investigated in detail. [4][5][6][7][8] Previous density functional theory ͑DFT͒ studies were confined to predicting the structure of ordered Sn 1−x Ge x alloys.…”

Effect of adsorbed Sn on Ge diffusivity on Si(111) surface

“…The effects of a Sn adlayer on the initial stages of Ge growth on Si are described in Refs. [7,[9][10][11][12][13].…”