Simultaneous two color ir detector having common middle layer metallic

Abstract

An array of dual-band HgCdTe radiation detectors (10) wherein individual detectors include a first layer (14) having a first type of electrical conductivity and a bandgap selected for absorbing radiation within a first spectral band. The radiation detectors also each include a second layer (16) overlying the first layer. The second layer has a second type of electrical conductivity that is opposite the first type of electrical conductivity. Each radiation detector further includes a third layer (18) overlying the second layer, the third layer having the first type of electrical conductivity and a bandgap selected for absorbing radiation within a second spectral band. The first and second spectral bands are selected from SWIR, MWIR, LWIR, and VLWIR. The first, second and third layers are contained within at least one mesa structure (10a, 10b) that supports on a top surface thereof a first electrical contact (24) to the first layer and a second electrical contact (28) to the third layer. The at least one mesa structure further supports on a sidewall region (10b') thereof an electrical contact (30) to the second layer. The sidewall electrical contact is coupled to an electrically conductive bus that is conductively coupled in common to mesa structure sidewall electrical contacts of the plurality of radiation detectors. As a result, each radiation detector site is simplified in construction, and may be reduced in area over a site wherein a separate (third) contact, such as an indium bump, is required to contact the second layer.