Bo Wen Jia

Formation of periodic interfacial misfit dislocation array at the InSb/GaAs interface via surface anion exchange

The relationship between growth temperature and the formation of periodic interfacial misfit (IMF) dislocations via the anion exchange process in InSb/GaAs heteroepitaxy was systematically investigated. The microstructural and electrical properties of the epitaxial layer were characterized using atomic force microscope, high-resolution x-ray diffraction, transmission electron microscopy, and Hall resistance measurement. The formation of interfacial misfit (IMF) dislocation arrays depended on growth temperature. A uniformly distributed IMF array was found in a sample grown at 310 °C, which also exhibited the lowest threading dislocation density. The analysis suggested that an incomplete As-for-Sb anion exchange process impeded the formation of IMF on sample grown above 310 °C. At growth temperature below 310 °C, island coalescence led to the formation of 60° dislocations and the disruption of periodic IMF array. All samples showed higher electron mobility at 300 K than at 77 K.

Mid-infrared to ultraviolet optical properties of InSb grown on GaAs by molecular beam epitaxy

Spectroscopic ellipsometry was used to investigate the optical properties of an InSb film grown on a GaAs (100) substrate, and to compare the optical properties of InSb film with those of bulk InSb. The film was grown by molecular beam epitaxy under conditions intended to form 90° misfit dislocations at the InSb-GaAs interface. The complex dielectric function obtained in a wide spectroscopic range from 0.06–4.6 eV shows the critical point transitions E0, E1, E1 + Δ1, E0′, and E2. The amplitudes, energy transitions, broadenings, and phase angles have been determined using a derivative analysis. Comparing film and bulk critical point results reveal that the epitaxial film is nearly relaxed and has bulk-like optical characteristics.

Hetero-integration of GaSb channel on silicon with ultra-thin buffer utilizing interfacial misfit dislocations

III-V semiconductors have attracted considerable interest as channel material in the transistor applications due to their relatively high carrier mobility compared to silicon. Among III-V semiconductors, GaSb and InAs are particularly interested due to their high hole mobility (1000 cm2V-1s-1) and electron mobility (40000 cm2V-1s-1), respectively. Furthermore, small lattice mismatch between GaSb and InAs benefit the integration of both materials on a single platform for pFET and nFET applications, respectively. However, large lattice mismatch between both materials and silicon poses a great challenge to integrate both materials on silicon platform. The problem of large lattice mismatch could be overcome by hetero-integration of III-V semiconductors on silicon substrate. Several hetero-integration methods such as aspect ratio trapping and thick graded buffer have been reported. In this report, we report hetero-integration of GaSb directly on Si substrate using self-assembled interfacial misfit (IMF) dislocations to relieve large lattice strain between GaSb and Si.