Figure 3
Cross sectional HR-STEM and AFM analysis of epitaxial InAs layers grown in a wide-field of micrometer size on Si substrate. (a,b) HR-STEM image illustrating the crystallographic quality beyond a few atomic layers from the Si substrate and lattice parameter of both Si substrate and InAs epitaxial layer and AFM surface scan with a root-mean-square roughness = 0.13 nm over a scan area of 1 μm × 0.5 μm of a 7 nm InAs layer grown in a 2 μm × 2.5 μm STI defined area on Si(111). The inset shows 9 InAs atoms for 10 Si atoms at the interface. The vertical (111) lattice constant correspond to the values of relaxed InAs and Si. (c) HR-STEM image of the interfacial region of a 40 nm InAs epitaxial layer grown in a 1 μm × 50 nm STI defined area on Si(100). The vertical (100) and horizontal (110) lattice parameters correspond to the values of relaxed InAs and Si. A periodic array of misfit dislocations at the Si-InAs interface accommodate the lattice mismatch (see inset) with 10 Si atoms accommodating 9 InAs atoms.
