High-resolution topographs of long-wave multi-element HgCdTe PC detector arrays were taken with synchrotron radiation white-beam topography. A number of crystal defects were revealed in the detecting elements of the multi-element detector arrays, such as lattice distortion zones, subgrain boundaries and slip planes. The experimental results show that there is a correlation between the performances of multi-element detector arrays and the defects in their active areas; that the stress state of HgCdTe device chips is greatly affected by device technologies; and that the lattice perfection of the detecting elements of multi-element detector arrays reflects the effect of device technologies on the stress state of HgCdTe device chips.