Reduced Dislocation Introduction in III–V/Si Heterostructures with Glide-Enhancing Compressively Strained Superlattices
- The Ohio State Univ., Columbus, OH (United States)
The novel use of a GaAsyP1-y/GaP compressively-strained superlattice (CSS) to provide enhanced control over misfit dislocation (MD) evolution and threading dislocation density (TDD) during GaP/Si metamorphic heteroepitaxy is demonstrated. Here, the insertion of the CSS just after critical thickness, and thus prior to substantial dislocation introduction, is found to yield significantly reduced TDD in relaxed, 500 nm thick, n-type GaP/Si versus comparable control samples. The impact of CSS period count on average TDD and the overall dislocation network morphology was examined, supported by quantitative microstructural characterization, revealing a nearly 20× relative TDD reduction (to 2.4 ± 0.4×106 cm-2) with a 3-period CSS structure. A similarly low TDD (3.0 ± 0.6×106 cm-2) is maintained when the resultant n-GaP/Si virtual substrate is used for the growth of a subsequent n-type GaAs0.75P0.25-terminal GaAsyP1-y step-graded metamorphic buffer. Although the physical mechanism for TDD reduction provided by these structures is not yet entirely understood, this initial work suggests that enhanced glide dynamics of MDs at or within the CSS placed early in the growth leads to a reduction in the total number of dislocations introduced overall, as opposed to annihilation-based reduction that occurs in conventional strained-layer superlattice dislocation filter approaches.
- Research Organization:
- The Ohio State Univ., Columbus, OH (United States)
- Sponsoring Organization:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE); National Science Foundation Graduate Research Fellowship; National Science Foundation (NSF)
- Grant/Contract Number:
- EE0007539; DGE-1343012; DGE-1650114; 1708957
- OSTI ID:
- 1784258
- Journal Information:
- Crystal Growth and Design, Vol. 20, Issue 10; ISSN 1528-7483
- Publisher:
- American Chemical SocietyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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