BULK LIFETIME DETERMINATION OF ETCH-THINNED INSB WAFERS FOR 2-DIMENSIONAL INFRARED FOCAL PLANE ARRAY

The bulk lifetime of etch-thinned InSb wafers, with lithography on both sides, has been determined. A device was specially designed to directly measure the diffusion length of the etch-thinned layer. The diffusion length was found to be approximately 35-mu-m at 77 K, which yields a lifetime of approximately 250 ns. No degradation to the semiconductor due to the thinning process, the passivation on both sides, possible defects or mechanical stress in the thinned layer, or due to other fabrication processes was found. The reported measurements characterize the fabrication technology of the etch-thinned and processed InSb wafers, designed for backside-illuminated two-dimensional detector arrays for an infrared hybrid focal plane.