Simultaneous two color IR detector having common middle layer metallic contact

Claim 1

An array comprised of a plurality of radiation detectors, individual ones of said radiation detectors comprising: a first layer comprised of Group II-VI semiconductor material, said first layer having a first type of electrical conductivity and a bandgap selected for absorbing radiation within a first spectral band; a second layer overlying said first layer, said second layer being comprised of Group II-VI semiconductor material, said second layer having a second type of electrical conductivity that is opposite the first type of electrical conductivity; and a third layer overlying said second layer, said third layer being comprised of Group II-VI semiconductor material, said third layer having the first type of electrical conductivity and a bandgap selected for absorbing radiation within a second spectral band; wherein said first, second and third layers are contained within at least one mesa structure supporting on a top surface thereof a first electrical contact to said first layer and a second electrical contact to said third layer, said at least one mesa structure further supporting on a sidewall thereof an electrical contact to said second layer, said sidewall electrical contact being coupled to an electrically conductive bus that is conductively coupled to mesa structure sidewall electrical contacts of said plurality of radiation detectors.

Claim 10

A method for fabricating an array of photodetector sites, individual ones of the photodetector sites being responsive to electromagnetic radiation having wavelengths within at least two spectral bands of wavelengths, comprising the steps of: providing a substrate; forming a first layer comprised of Group II-VI semiconductor material upon a first surface of the substrate, the first layer having a first type of electrical conductivity and a bandgap selected for absorbing radiation within a first spectral band; forming a second layer upon the first layer, the second layer being comprised of Group II-VI semiconductor material having a second type of electrical conductivity that is opposite the first type of electrical conductivity; forming a third layer upon the second layer, the third layer being comprised of Group II-VI semiconductor material having the first type of electrical conductivity and a bandgap selected for absorbing radiation within a second spectral band; forming a plurality of orthogonally disposed trenches through the third, second and first layers for defining a plurality of mesa structures, individual ones of said mesa structures having a top surface and sloping sidewall surfaces, wherein a given photodetector site of the array is comprised of at least one mesa structure; passivating exposed surfaces of said plurality of mesa structures with a passivation layer; for said at least one mesa structure of each of the photodetector sites, applying first and second electrical contacts over the top surface of the mesa structure for conductively coupling to the first and third layers within the mesa structure, and applying a third electrical contact to a sidewall of the mesa structure for conductively coupling through the passivation layer to the second layer; and applying an electrically conductive bus over the passivation layer for conductively coupling to the third electrical contacts of individual ones of the photodetector sites for conductively coupling together in common the second layers of a plurality of the photodetector sites.

Claim 11

A method for fabricating an array of photodetector sites, individual ones of the photodetector sites being responsive to electromagnetic radiation having wavelengths within at least two spectral bands of wavelengths, comprising the steps of: providing a substrate; forming a first layer comprised of Group II-VI semiconductor material upon a first surface of the substrate, the first layer having a first type of electrical conductivity and a bandgap selected for absorbing radiation within a first spectral band; forming a second layer upon the first layer, the second layer being comprised of Group II-VI semiconductor material having a second type of electrical conductivity that is opposite the first type of electrical conductivity; forming a third layer upon the second layer, the third layer being comprised of Group II-VI semiconductor material having the first type of electrical conductivity and a bandgap selected for absorbing radiation within a second spectral band; forming a plurality of orthogonally disposed trenches through the third, second and first layers for defining a plurality of mesa structures, individual ones of said mesa structures having a top surface and sloping sidewall surfaces, wherein a given photodetector site of the array is comprised of at least one mesa structure; passivating exposed surfaces of said plurality of mesa structures with a passivation layer; for said at least one mesa structure of each of the photodetector sites, applying first and second electrical contacts over the top surface of the mesa structure for conductively coupling to the first and third layers within the mesa structure, and applying a third electrical contact to a sidewall of the mesa structure for conductively coupling through the passivation layer to the second layer; and applying an electrically conductive bus over the passivation layer for conductively coupling to the third electrical contacts of individual ones of the photodetector sites for conductively coupling together in common the second layers of a plurality of the photodetector sites.