Thick In_xGa_1-xAs metamorphic buffer layers (MBLs) were grown by hydride vapor phase epitaxy (HVPE). Relationships between MBL properties and grading rate, cap layer thickness, final x_InAs, and deposition temperature (T_D) were explored. The MBLs were characterized by measurement of in-plane residual strain (ε_ll) at the surface by reciprocal space mapping, threading dislocation density (TDD) by etch pit studies and cathodoluminescence, and root mean square (RMS) surface roughness by atomic force microscopy (AFM). ε_ll and surface roughness were not affected much by grading rate, as MBLs with thick grading regions had similar properties to those with thinner grades. The use of a thick capping layer led to higher levels of strain relaxation compared to MBLs with thin caps.  MBLs graded in discrete steps had similar properties to linearly graded MBLs indicating that strain was not trapped in the individual steps. TDD was generally correlated with ε_ll , with more relaxed samples containing higher levels of dislocations. ε_ll increased almost linearly with x_InAs, though total relaxation increased as well. Relaxation as a function of x_InAs could adequately be described by an equilibrium model, indicating that the MBLs reached a work hardened state where relaxation is controlled by dislocation interactions. TDD was constant from x = 0 to ~0.2, then increased exponentially. This behavior could not be described by theory, but was fit to an empirical model that previously described TDD in the In_xGa_1-xP system. The effect of T_D on ε_ll and TDD was somewhat unclear since it strongly affected growth rate and x_InAs. T_D did have a clear effect on RMS roughness, as samples grown with high T_D (~770°C) exhibited a significant increase in surface roughness. Tilting behavior in these layers was measured by omega-phi mapping. It was found that tilt magnitude typically increased with x_InAs and did not depend on grading style. The direction of the tilt was initially random on nominally (100) oriented substrates and changed as grading continued while exhibiting hysteresis. MBLs grown on 4° miscut substrates tilted in the almost exact opposite direction of the miscut, and the tilt magnitude for a given composition was greater. Defect structure of select samples was analyzed by TEM. It was found that threading dislocations serve as a source of misfit dislocations in subsequent layers, while no threading segments could be observed in the capping layers. The potential for device incorporation through use of chemical mechanical polishing will be demonstrated.

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