US Government As Represented by the Secretary of the Army

John H Dinan

William A Gutierrez

Phillip R Boyd

Michael Martinka

Andrew J Stoltz, Jr

Andrew W Kaleczyc

J David Benson

Leo Anthony Almeida

A lithographic imaging method of the present invention includes the initial step of providing a substrate made from Mercury, Cadmium and Telluride materials (HgCdTe). The HgCdTe substrate is coated with a diazonaphthoquinone (DNQ) Novolak photoresist material to establish an imaging medium. The imaging medium is exposed to an image pattern and then developed in a tetra-methyl ammonium hydroxide (TMAH) solution. The TMAH solution includes a fullerene (C) material dissolved therein to retard the subsequent etching of the imaging medium. The incorporation of fullerene into the photoresist material indirectly via the developing solution avoids the solubility and ultraviolet (UV) absorbance disadvantages inherent in adding fullerenes directly to the photoresist prior to placement on the substrate. After development, the imaging medium is etched to transfer the recorded image pattern to the substrate. The fullerene cooperates with the photoresist material to slow the etching process, which allows for a highly reticulated HgCdTe detectors and IR images having greatly enhanced resolution.

Fullerene addition in photoresist via incorporation in the developer

Successive layers of a II-VI ternary buffer layer and a II-VI ternary nar-bandpass infrared-absorbing layer are grown by MBE on a III-V binary substrate with low surface defect density. The composition of the buffer layer is chosen to lattice match with the infrared-absorbing layer.

Infrared epitaxial detector structure and method of making same

A method of making infrared detectors on a substrate of mercury cadmium turide (HgCdTe) or mercury zinc telluride (HgZnTe). The steps include those of preparing the substrate, etching and passivating it, and placing it in the ultra-high vaccuum environment of a molecular beam epitaxy apparatus. While in the apparatus, one or more layers of zinc cadmium telluride (ZnCdTe) are deposited. When the ZnCdTe deposition is finished, the substrate is removed from the apparatus and the detectors are delineated lithographically.

Hybrid epitaxial growth process

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Alexandria, VA, United States of America

John H Dinan