Specular and diffuse reflectivity from thin films containing misfit dislocations

X-ray study of antiphase domains and their stability in MBE grown GaP on Si

“…1 represents the (0 0 2) and (0 0 4) RC scans in angular units normalized to the same intensity maximum to highlight the similarity of the thin contributions. They are also similar to the Si(0 0 4) substrate-RC with a slightly larger integral breadth (IB) suggesting that this contribution is resolution-limited [12] and attests for high overall crystalline quality of the GaP epitaxial layer highly coherently linked to the substrate (due to the epitaxy). For the main graph, the (0 0 2) and (0 0 4) peaks are normalized to the same integrated intensity of the thin peak.…”

“…The relative intensity of the broad contribution is clearly much higher for the (0 0 2) than for the (0 0 4). The thin contribution vanishes on (0 0 6) due to an exponential damping versus the lattice plane displacement [12]. The relative importance of broadening on (0 0 2) cannot be explained either by a resolution effect when converting the scans into reciprocal space units, or by a pollution of the GaP(0 0 4) by a contribution from the Si reflection.…”

“…Indeed, lattice strain field should induce a rapid decrease in the quality factor with an increase in l coordinate as observed for dynamic displacement (thermal diffuse scattering) [7] and [13] or for static strain [14]. The effect of mosaicity alone should induce a linear increase in the IB with l [12] and [15]. The actual observed effect is thus interpreted by the presence of coherently linked APD (that does not break the long-range lateral order shown by (0 0 4) intense sharp peak) as already shown by Blaschko et al for RbSCN using neutron scattering [16].…”

Structural study of GaP layers on misoriented silicon (001) substrates by transverse scan analysis

“…In addition, the width of the broad component is constant in units of S x . 11 Thus, IB stays constant as a function of increasing l. On the other hand, strong disorder created by crystal mosaicity may make the higher order reflection Bragg peaks invisible. Furthermore, the angular width of diffuse scattering is then typically constant and independent of S z (Ref.…”

“…However, strain in crystals can also create rotational disorder (i.e., mosaicity) which is observed at the strong disorder limit. 10,11 The relation between the line shape of (00l)-reflection and index l can be used to define what is causing the disorder. Typically, weak disorder is manifested as a prominent Bragg component.…”