Infra-red radiation imaging devices and methods for their manufacture

Abstract

An array of photovoltaic infrared radiation detector elements are formed in a body of infrared-sensitive material, e.g. of cadmium mercury telluride. The body is present on a circuit substrate, which may comprise a silicon CCD for processing signals from the detector elements. An array of regions of a first conductivity type, which form the p-n junctions of each detector element with an adjacent body part of opposite conductivity type, extend through the thickness of the body at side walls of an array of apertures. Each aperture is associated with a detector element and is preferably formed by ion etching. These regions of the first conductivity type are electrically connected to substrate conductors in a simple and reliable manner by a metallization layer in the apertures, without rendering a significant area of the detector insensitive to radiation imaged onto the upper surface of the body. At least the back surface of the detector body has a passivating layer over the area around and between the apertures to enhance detector element performance. This back surface is secured to the circuit substrate by a layer of electrically insulating adhesive. The main body part is connected to a substrate conductor by a metallization at a surface portion which is outside of the area of the back surface and which is between the apertures. The resulting device is a closely-packed array of high performance detector elements on a circuit substrate. The spacing between adjacent apertures is 100 microns or less.