Abstract: Compact electrical connections (4) are formed on side-walls (1) of an infrared detector element having a step structure (1 to 3) over which a conductive layer (40) is deposited. Using a directional etching treatment, such as ion milling, the conductive layer (40) is removed from at least the bottom (3) of the step structure but is left lining the side-wall (1) as the connection (4). This permits formation of connections (4 and 44) in compact dense arrays, including plural-wavelength arrays in stacked bodies (10 and 20) on a circuit substrate (30).

Abstract: An imaging device arrangement comprises infra-red radiation detector elements (10) and signal-processing circuitry including at least one charge-transfer line (30). The detector elements (10) are preferably cadmium mercury telluride photodiodes formed in a common body or body portion which is secured to a substrate (e.g. of silicon) comprising the charge-transfer line (30). Each detector element (10) is connected between an input connection (2,3) of the charge-transfer line (30) and a common electrical connection (4). At least one storage electrode (62) and at least one subtraction gate (63) are present at each input connection (2,3) for subtracting at least one portion (77) of the charge-signal so that only a portion (78) of the charge-signal from each detector element (10) is transferred along the charge-transfer line (30).