Abstract: Disclosed are minority carrier based mercury-cadmium telluride (HgCdTe) infrared detectors and arrays, and methods of making, are disclosed. The constructions provided by the invention enable the detectors to be used at higher temperatures, and/or be implemented on less expensive semiconductor substrates to lower manufacturing costs. An exemplary embodiment a substrate, a bottom contact layer disposed on the substrate, a first mercury-cadmium telluride layer having a first bandgap energy value disposed on the bottom contact layer, a second mercury-cadmium telluride layer having a second bandgap energy value that is greater than the first bandgap energy value disposed on the first mercury-cadmium telluride layer, and a collector layer disposed on the second mercury-cadmium telluride layer, wherein the first and second mercury-cadmium telluride layers are each doped with an n-type dopant.

Abstract: Disclosed are minority carrier based mercury-cadmium telluride (HgCdTe) infrared detectors and arrays, and methods of making, are disclosed. The constructions provided by the invention enable the detectors to be used at higher temperatures, and/or be implemented on less expensive semiconductor substrates to lower manufacturing costs. An exemplary embodiment a substrate, a bottom contact layer disposed on the substrate, a first mercury-cadmium telluride layer having a first bandgap energy value disposed on the bottom contact layer, a second mercury-cadmium telluride layer having a second bandgap energy value that is greater than the first bandgap energy value disposed on the first mercury-cadmium telluride layer, and a collector layer disposed on the second mercury-cadmium telluride layer, wherein the first and second mercury-cadmium telluride layers are each doped with an n-type dopant.

Abstract: Disclosed are minority carrier based mercury-cadmium telluride (HgCdTe) infrared detectors and arrays, and methods of making, are disclosed. The constructions provided by the invention enable the detectors to be used at higher temperatures, and/or be implemented on less expensive semiconductor substrates to lower manufacturing costs. An exemplary embodiment a substrate, a bottom contact layer disposed on the substrate, a first mercury-cadmium telluride layer having a first bandgap energy value disposed on the bottom contact layer, a second mercury-cadmium telluride layer having a second bandgap energy value that is greater than the first bandgap energy value disposed on the first mercury-cadmium telluride layer, and a collector layer disposed on the second mercury-cadmium telluride layer, wherein the first and second mercury-cadmium telluride layers are each doped with an n-type dopant.

Abstract: Disclosed are minority carrier based mercury-cadmium telluride (HgCdTe) infrared detectors and arrays, and methods of making, are disclosed. The constructions provided by the invention enable the detectors to be used at higher temperatures, and/or be implemented on less expensive semiconductor substrates to lower manufacturing costs. An exemplary embodiment a substrate, a bottom contact layer disposed on the substrate, a first mercury-cadmium telluride layer having a first bandgap energy value disposed on the bottom contact layer, a second mercury-cadmium telluride layer having a second bandgap energy value that is greater than the first bandgap energy value disposed on the first mercury-cadmium telluride layer, and a collector layer disposed on the second mercury-cadmium telluride layer, wherein the first and second mercury-cadmium telluride layers are each doped with an n-type dopant.

Abstract: Disclosed are minority carrier based mercury-cadmium telluride (HgCdTe) infrared detectors and arrays, and methods of making, are disclosed. The constructions provided by the invention enable the detectors to be used at higher temperatures, and/or be implemented on less expensive semiconductor substrates to lower manufacturing costs. An exemplary embodiment a substrate, a bottom contact layer disposed on the substrate, a first mercury-cadmium telluride layer having a first bandgap energy value disposed on the bottom contact layer, a second mercury-cadmium telluride layer having a second bandgap energy value that is greater than the first bandgap energy value disposed on the first mercury-cadmium telluride layer, and a collector layer disposed on the second mercury-cadmium telluride layer, wherein the first and second mercury-cadmium telluride layers are each doped with an n-type dopant.

Abstract: Disclosed are minority carrier based mercury-cadmium telluride (HgCdTe) infrared detectors and arrays, and methods of making, are disclosed. The constructions provided by the invention enable the detectors to be used at higher temperatures, and/or be implemented on less expensive semiconductor substrates to lower manufacturing costs. An exemplary embodiment a substrate, a bottom contact layer disposed on the substrate, a first mercury-cadmium telluride layer having a first bandgap energy value disposed on the bottom contact layer, a second mercury-cadmium telluride layer having a second bandgap energy value that is greater than the first bandgap energy value disposed on the first mercury-cadmium telluride layer, and a collector layer disposed on the second mercury-cadmium telluride layer, wherein the first and second mercury-cadmium telluride layers are each doped with an n-type dopant.

Abstract: An avalanche photodiode is operated in avalanche mode at a selected reverse bias that achieves high gain and a reduced gain normalized dark current.

Abstract: A photodiode for detection of preferably infrared radiation capable of detecting two different wavelengths wherein photons are absorbed in one region and detected in another. In one example embodiment, an absorbing P region is abutted with an N region of lower doping such that the depletion region is substantially (preferably completely) confined to the N region. The N region is also chosen with a larger bandgap than the P region, with compositional grading of a region of the N region near the P region. This compositional grading mitigates the potential barrier between the respective bandgaps. Under first voltage conditions a potential barrier prevents minority carriers from moving from the P region to the N region, but photons of energy large enough to generate minority carriers within the N region are detected. Under reverse bias, the barrier is substantially reduced or disappears, allowing charge carriers to move from the absorbing P region into the N region (and beyond) where they are detected.

Abstract: A photodiode for detection of preferably infrared radiation wherein photons are absorbed in one region and detected in another. In one example embodiment, an absorbing P region is abutted with an N region of lower doping such that the depletion region is substantially (preferably completely) confined to the N region. The N region is also chosen with a larger bandgap than the P region, with compositional grading of a region of the N region near the P region. This compositional grading mitigates the barrier between the respective bandgaps. Under reverse bias, the barrier is substantially reduced or disappears, allowing charge carriers to move from the absorbing P region into the N region (and beyond) where they are detected. The N region bandgap is chosen to be large enough that the dark current is limited by thermal generation from the field-free p-type absorbing volume, and also large enough to eliminate tunnel currents in the wide gap region of the diode.

Abstract: A photodiode for detection of preferably very long wavelength infrared radiation wherein low energy photons are absorbed in one region and detected in another. In one example embodiment, an absorbing P region is abutted with an N region of lower doping such that the depletion region is substantially (preferably completely) confined to the N region. The N region is also chosen with a larger bandgap than the P region, with compositional grading of a region of the N region near the P region. This compositional grading mitigates the barrier between the respective bandgaps. Under reverse bias, the barrier is substantially reduced or disappears, allowing charge carriers to move from the absorbing P region into the N region (and beyond) where they are detected. The N region bandgap is chosen to be large enough that the dark current is limited by thermal generation from the field-free p-type absorbing volume, and also large enough to eliminate tunnel currents in the wide bandgap region of the diode.

Abstract: Group II-VI thin film transistors, a method of making same and a monolithic device containing a detector array as well as transistors coupled thereto wherein, according to a first embodiment, there is provided a group II-VI insulating substrate, a doped layer of a group II-VI semiconductor material disposed over the substrate, an insulating gate region disposed over the doped layer, a pair of spaced contacts on the doped layer providing source and drain contacts, a gate contact disposed over the insulating gate region, an insulating layer disposed over exposed regions of the substrate, doped layer, insulating gate region and contacts and metallization disposed on the insulating layer and extending through the insulating layer to the contacts. The thickness of the doped layer is less than the maximum depletion region thickness thereof.

Abstract: Group II-VI thin film transistors, a method of making same and a monolithic device containing a detector array as well as transistors coupled thereto wherein, according to a first embodiment, there is provided a group II-VI insulating substrate, a doped layer of a group II-VI semiconductor material disposed over the substrate, an insulating gate region disposed over the doped layer, a pair of spaced contacts on the doped layer providing source and drain contacts, a gate contact disposed over the insulating gate region, an insulating layer disposed over exposed regions of the substrate, doped layer, insulating gate region and contacts and metallization disposed on the insulating layer and extending through the insulating layer to the contacts. The thickness of the doped layer is less than the maximum depletion region thickness thereof.

Abstract: Photocapacitive detectors with varying bandgap Hg.sub.1-x Cd.sub.x Te (604) for two color detection and one color detection with increased potential well capacity. Preferred embodiments include a transparent insulated gate (608) on a top layer (632) of Hg.sub.0.8 Cd.sub.0.2 Te over a lower layer (634) of Hg.sub.0.83 Cd.sub.0.27 Te for detection of two infrared colors by varying gate potential to either confine the potential well to the top layer or to extend the potential well to both layers. Also, methods of compositionally grading the Hg.sub.1-x Cd.sub.x Te by fluid transport plus diffusion.

Abstract: The disclosure relates to oxide-semiconductor interfaces which are grown with varying amounts of fixed positive (or negative) charge. The invention utilizes these different values to form a channel stop for a charge transfer device. For HgCdTe two different oxides are used, namely, those produced by wet anodization (having large values of fixed positive charge) and plasma oxidation (having low values of fixed charge). The voltage range of operation of the active gate is determined by the difference in fixed positive charge for these regions and the insulator thicknesses.

Abstract: The disclosure relates to a stepped insulator process for HgCdTe infared focal plane devices, the insulator being a combination of two insulator materials, ZnS and SiO, which differ in dielectric constant and chemical reactivity. The structure is patterned on HgCdTe which has an accumulated surface region. The resulting configuration significantly reduces pin hole short circuits introduced during via etching and improves the operating range (channel stopping action) for a given step height over that of ZnS alone.

Abstract: The disclosure relates to a method for reducing impurity concentration in mercury cadmium telluride alloys wherein impurities are attracted to a region saturated with second phase tellurium during annealing in a saturated mercury atmosphere where the second phase tellurium and the impurities attracted thereto can be removed by polishing, etching, grinding, or the like.

Abstract: The disclosure relates to a method for making extrinsically doped HgCdTe alloys containing Cu, Ag, or Au or other dopant impurity whereby the excess tellurium in the core is annihilated (stoichiometrically compensated by excess in-diffusing Hg) and the dopant impurities are then permitted to randomly move through the slab to provide for homogeneity thereof. A post-annealing step of much greater than normal temperature-time length than was provided in the prior art is used. A standard post-annealing step in a saturated mercury vapor atomosphere leaves second phase tellurium (and gettered impurities) at the center of the slab, and longer term post-annealing negates this situation by annihilating the second phase tellurium in the slab and thus permitting the impurities to randomly travel by solid state diffusion throughout the slab to ultimately be distributed therein in a homogeneous manner.

Abstract: A monolithic charge-coupled infrared imaging device (CCIRID) is fabricated on N-type HgCdTe. A native oxide layer on the semiconductor is used, in combination with ZnS to provide first level insulation. An opaque field plate over first level insulation is provided for signal channel definition. Second level insulation (ZnS) is substantially thicker than the first level, and is provided with a stepped or sloped geometry under the first level gates. Input and output diodes are provided with MIS guard rings to increase breakdown voltages.

Abstract: An infrared charge transfer device (CTD) imaging system is disclosed which includes an optic system for focusing infrared energy emanating from a scene, a detector matrix for receiving the focused infrared energy and converting it to electrical signals representative of the intensity of the infrared energy, and a video processor for processing the electrical signals into video signals. The detector matrix of the system is a plurality of IR detector cells arranged in rows and columns. Each detector cell includes a substrate of semiconductor material, an integrating electrode, a drain electrode, a transfer electrode and insulating layers. The integrating electrode is centrally disposed with respect to the drain and transfer electrodes with the integrating electrode in a spaced relationship with the drain electrode. The integrating and drain electrodes form first level MIS electrodes on the semiconductor substrate.

Abstract: An infrared charge transfer device (CTD) imager system is disclosed which includes an optic system, a charge transfer device detector matrix and a signal processor. The optic system focuses infrared energy from a scene onto the detector matrix. The detector matrix produces electrical signals representative of the impinging energy and the signal processor processes the electrical signals into video signals. The CTD detector matrix comprises a plurality of charge injection devices (CID). Each CID has an IR sensitive area, and two metal/insulator/semiconductor gate electrodes surrounded by a field plate. One, a column gate electrode, is centrally located within the IR sensitive area and the other, a row gate electrode, surrounds the column gate electrode.