HgCdTe array detector

More recently, HgCdTe array detectors have become available that respond in the range 3500-900 cm ... 

Two arrays of HgCdTe photovoltaic detectors with pn-junctions of different sizes are combined in US-A-4517464 to form a device which has an increased functionality when exposed to ionizing radiation. 

Reine (1983) Status of HgCdTe Technology, by M. B. Reine. Infrared Detectors, W. L. Wolfe, ed., Proc SPIE 443,2. Shows a 60 element HgCdTe array. 

Both channels can accommodate 256x256 arrays, but the problem arises as to which detectors to choose — the HgCdTe arrays from Rodcwell or the InSb arrays from SBRC. The quandry is a bit like having two bottles of excellent Scotch whisky — which one do you drink Well, for a Scotsman like myself, the answer is easy — you drink them both And so we have incorporated both the BigCdTe and InSb technologies in this one instrument. 

The authors acknowledge finandal support from Hubble fellowships. The authors also acknowledge the Astrophysical Research Consortium for its support of the Detector Devdopment Consortium in the production of the NICMOS 3 detector used in this work. We are indebted to the Rockwell sdentists for their efforts in devdoping these excellent HgCdTe arrays, and to the NSF for support. We also thank the people involved in building the Campanas camera, S.E. Persson, S.C. West, D.M. Carr, and D.C. Murphy. 

The detector disclosed in US-A-S006711 refers to an HgCdTe multi-element detector array formed on a sapphire substrate. The elements have individual electrodes and a common electrode. When the electrodes are formed by a lift-off process, the maximum thickness of the metal layer forming the electrodes is limited due to the operational characteristics of the lift-off process. This results in a non-negligible resistance of the common electrode, which gives the device a low sensitivity. To reduce the resistance of the common electrode, an auxiliaiy electrode is formed on an aperture plate such that when the aperture plate is assembled onto the detector, the auxiliary electrode is pressed onto the common electrode. 

Mesas in the mirror image of a desired array pattern are formed on the surface of a bar of HgCdTe by etching to a depth greater than the desired final detector array thickness. A lead pattern 14 is formed on a sapphire substrate 12 with contact pads 16 plated to a thickness greater than the final detector thickness. The bar is turned over and the etched surface bonded to the substrate by an epoxy resin 18 to form an unit. The unit is lapped to final detector thickness to form a coplanar surface of the lead pattern contact pads, detector contact areas,... 

A semiconductor substrate 10 of CdTe is doped slightly conductive, and is coated with an ohmic contact layer 11. An array of photo-conductive detectors 12 is formed on the substrate in a comb shape. The array is covered by a thin layer 13 of CdTe, except for perforations made to allow ohmic connections. Conductive leads 14 and 15 are formed on the layer 13. Each detector includes an HgCdTe bar 16 with two cavities formed therein. The bottom of each cavity is covered with an ohmic contact metal of indium. On top of the bar is a continuation of the CdTe layer 13 except for the area of the cavity in 16. Lead 14 is formed over layer 13 and forms a dimple 14a where it overlies the cavity and covers a contact 17. The region under dimple 15a has the same construction as the region under 14a. Layer 11 and contact 17 form ohmic connections with the substrate and the bar respectively. The substrate and layer 13 form... 

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