Microstructure of lateral epitaxial overgrown InAs on (100) GaAs substrates

Abstract

Substantial defect reduction was achieved in InAs/GaAs by lateral epitaxial overgrowth in which InAs was grown on mask-patterned ͑100͒ GaAs with stripe-shaped windows of various widths by metalorganic chemical vapor deposition. The InAs growth morphology, crystal quality, and microstructure were evaluated using double-crystal x-ray rocking curves and scanning and transmission electron microscopy. The microstructure of the InAs grown on mask-free control samples was comprised of micron-scale misoriented grains and dislocations at a density of 10 11 cm Ϫ2 . As the width of the mask openings decreased to 0.8 m, the rocking curves narrowed, grain boundaries disappeared and the dislocation density decreased to Ͻ10 7 cm Ϫ2 . The distribution of the remaining defects suggests substantial changes in microstructural development when the window width is Շ1 m.

Heterogeneous integration of InAs on W/GaAs by MOVPE

“…For this purpose, a sample with short growth time was grown and 10 nm of equivalent InAs layer thickness was deposited at 600ºC. Due to large lattice mismatch, Stranski Krastanow (SK) islands formed on the substrate [5] with nonuniform island sizes, ranging in diameter from less than 2 nm up to 20 nm. The islands show no prefential nucleation sites outside the grating, while the situation is different inside the grating, Fig.…”

Electrical characterization of thin InAs films grown on patterned W∕GaAs substrates

“…The InAs lateral overgrowth starts after 15 nm of InAs deposition ͑height of W͒ and a better structural quality of the overgrown layer is achieved as compared to the reported heteroepitaxial overgrowth of InAs. 8 Our samples are grown under a low V/III ratio and a low growth temperature to favor the growth on high energy facets that form along the overgrowth direction. We observe that dislocations are more frequent at the unpatterned InAs/ GaAs interface, whereas W patterns yield lower defect density in the overgrown layer.…”

InAs growth and development of defect microstructure on GaAs

“…InAs thin films were deposited on SI GaAs (1 0 0) substrates in a horizontal MOCVD reactor using trimethyl indium (TMIn) and arsine (AsH 3 ) as the growth precursors in H 2 carrier gas [11]. The substrates were annealed in arsine at 700 1C to desorb the native surface oxides and an initial 100 nm thick layer of GaAs was grown at 700 1C and a V/III ratio of 80.…”