Over the years, Fermionics has been supplying to the infrared industry with processed HgCdTe array wafers. These are high quality p-on-n hetrostructure wafers. The state-of-the-art linear as well as mosaic arrays have been fabricated and tested. In the recent successful Clementine I mission to the moon (January, 1994), the 128 x 128 HgCdTe mosaic array in the on-board long wavelength infrared camera was fabricated by Fermionics.
Typically, the customer has a special system application in mind which requires HgCdTe detector arrays in the focal plane. The engineering requirements are flowed down to Fermionics and detector specifications are determined. This translates into specific wafers needed to be processed. The photomasks are designed with the input from Fermionics to obtain mask level necessary to realize the arrays needed in the system. To accomplish the job, Fermionics will use home-grown cite substrate on which epitaxial heterostructure double-layers are grown. The diodes are delineated and passivated with a proprietary process.
Numerous processed wafers have been delivered with a variety of configuration and pixel dimensions. To qualify the processed wafers, the test structures on the sides of each wafer are evaluated which usually reflect the performance of the arrays in the center. The customer would process the wafers with In bumps and hybridize with its own signal processing chips.
Since Fermionics engineers are pioneers and experts in HgCdTe materials and detectors technologies, we are available as the consultant to assist in the development of HgCdTe epitaxy and detector processing technologies.