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Abstract

A variable bandgap infrared absorbing material, Hg.sub.1-x Cd.sub.x Te, is manufactured by use of the process termed MOCVD-IMP (Metalorganic Chemical Vapor Deposition-Interdifffused Multilayer Process). A substantial reduction in the dislocation defect density can be achieved through this method by use of CdZnTe layers which have a zinc mole fraction selected to produce a lattice constant which is substantially similar to the lattice constant of HgTe. After the multilayer pairs of HgTe and Cd.sub.0.944 Zn.sub.0.056 Te are produced by epitaxial growth, the structure is annealed to interdiffuse the alternating layers to produce a homogeneous alloy of mercury cadmium zinc telluride. The mole fraction x in Hg.sub.1-x (Cd.sub.0.944 Zn.sub.0.056).sub.x Te can be varied to produce a structure responsive to multiple wavelength bands of infrared radiation, but without changing the lattice constant. The alloy composition is varied by changing the relative thicknesses of HgTe and Cd.sub.0.944 Zn.sub.0.056 Te. A similar structure can also be fabricated using HgTe and lattice matched CdTe.sub.1-y Se.sub.y. Thus, a multi-band infrared absorbing material structure can be fabricated which has reduced dislocation defects, and thereby produce detectors with improved performance.

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