Infrared charge transfer device (ctd) system

Abstract

An infrared charge transfer device (CTD) imaging system is disclosed which includes an optic system for focusing infrared energy emanating from a scene, a detector matrix for receiving the focused infrared energy and converting it to electrical signals representative of the intensity of the infrared energy, and a video processor for processing the electrical signals into video signals. The detector matrix of the system is a plurality of IR detector cells arranged in rows and columns. Each detector cell includes a substrate of semiconductor material, an integrating electrode, a drain electrode, a transfer electrode and insulating layers. The integrating electrode is centrally disposed with respect to the drain and transfer electrodes with the integrating electrode in a spaced relationship with the drain electrode. The integrating and drain electrodes form first level MIS electrodes on the semiconductor substrate. The transfer gate forms a second level MIS electrode as to the semiconductor substrate and overlaps the space between the integrating and drain electrodes. In a second MIS embodiment the drain electrode is replaced by a diode formed in the semiconductor substrate. In both embodiments, the integrating electrodes are connected together in columns and the transfer electrodes are connected together in rows. In operation, the integrating electrode and the drain are on while a row of transfer electrodes are turned on and then off transferring the charge from wells under the integrating electrode to the drain well. The column voltages are sampled before and after the turn-on and turn-off of the integrating well the voltage difference on the column lines is proportional to the charge transferred and is used to indicate the intensity of the impinging infrared image. Charge collected by the drain is either injected to the substrate in the first embodiment or drained out the contact to the junction diode in the second embodiment.