Epitaxial growth of dissimilar materials on patterned substrates is a promising technique for defect-free, monolithic integration of various optoelectronic devices on a single chip. In this work we investigate the structural quality of Ge microcrystal arrays monolithically grown at temperatures ranging from 450 to 575 degrees C on patterned Si substrates. Using high resolution X-ray diffraction with reciprocal space mapping, we obtain the lattice parameters, strain and degree of relaxation. This structural analysis gives us insight in dislocation formation together with quantitative information about thermal relaxation and lattice bending.