MERCURY CADMIUM TELLURIDE SUBSTRATE FOR FOCAL PLANE ARRAYS

HIGH QUALITY WAFER OF MERCURY CADMIUM TELLURIDE ARE CRITICALLY NEEDED FOR THE FABRICATION OF INFRARED FOCAL PLANE ARRAYS. DEFENSE RELATED APPLICATIONS OF THESE ARRAYS INCLUDE: SURVEILLANCE, TARGET DETECTION, ACQUISITION AND TRACKING, MISSILE GUIDANCE, THERMAL IMAGING, NAVIGATIONAL AIDS AND NIGHT VISION. FOR OPERATION IN THE BACK-SIDE ILLUMINATED MODE IT IS REQUIRED THAT THE ACTIVE DEVICE LAYER OF MERCURY CADMIUM TELLURIDE BE DEPOSITED ON A SUITABLE SUBSTRATE MATERIAL. THE SUBSTRATE MATERIAL MUST MEET A NUMBER OF STRINGENT REQUIREMENTS AND THE DEVELOPMENT OF SUITABLE SUBSTRATE HAS BEEN A FORMIABLE TASK. RECENTLY XACTON HAS ACHIEVED A MAJOR BREAKTHROUGH IN THE MERCURY TELLURIDE TECHNOLOGY. BASED ON THIS, WE PROPOSED THE USE OF HIGH QUALITY WAFERS OF MERCURY CADMIUM TELLURIDE AS A SUBSTRATE MATERIAL FOR THE EPITAXIAL GROWTH OF ACTIVE LAYERS OF MERCURY CADMIUM TELLURIDE. THE SUBSTRATE CAN BE MADE TRANSPARENT TO THE INCOMING RADIATION BY TAILORING ITS COMPOSITION TO BE SLIGHTLY MORE CD RICH THAN THAT OF THE ACTIVE EPITAXIAL LAYER.