Z-Technology Arrangements

Z-technology arrangements for mercury cadmium telluride imagers are presented in this chapter. 

The use of the Z-technology [1 -3] results in a very compact detector unit. The detector unit is made by connecting a two-dimensional detector array to an end of a module formed by a layered structure. The layered structure comprises means for reading-out information from the detector array. 

One problem which arises when a detector array is attached to the face of a multi-layer module is the inability of the detector material to absorb forces generated by a mismatch of coefficient of thermal expansion between the detector array material and the module. Furthermore, it is difficult to isolate a fault that may be attributable to either the detector elements, module wiring or processing elements. 

In US-A-3852714 (Eocom Corporation, USA, 03.12.74) a two-dimensional electro-optical detector array is presented which has coupling conductors between the detectors and their respective amplifiers packaged three-dimensionally on multilayered modules. 

The module further comprises a flat end surface 124 to which a substrate 126 may be bonded. The substrate is of alumina or sapphire and has disposed thereon a mosaic array 3 of electro-optical detectors 4. The detectors are formed by etching or laser cutting of a mercury cadmium telluride layer which has been deposited on the substrate. Each detector is connected at one end 130 to a common reference terminal 132 and at the other end 136 to terminal 134. The substrate further comprises a pattern of through holes 138 and metal dots 140 such that each signal terminal 134 contacts a dot 140. The substrate 126 is aligned on the end surface 124 such that the metal dots 140 in each hole 138 contacts a conductor 114. As a result, each detector 4 is coupled to a pad 118. 

---