Optoelectronic sensor according to the principle of carrier injection

Abstract

The invention relates to an optoelectronic sensor with at least one sensor element according to the principle of carrier injection (CID), whereby the surface of a doped semiconductor body is faced by two closely adjoining electrodes insulated from one another and from the semiconductor surface by a thin insulation layer that are controllable via separate control circuits. The semiconductor body contains a more strongly doped area having the type of the semiconductor doping on its surface below one of the electrodes, which area extends slightly into the semiconductor surface lying below the other electrode. Thereby, a narrow potential barrier is formed between the two electrodes, for example, between a line electrode and a column electrode. When an optically generated charge under one electrode is displaced under the other electrode, then this narrow potential barrier prevents a flow back of the charge under the discharged electrode. This makes a floating readout possible, in which the couplings-in of the line circuits onto the column circuits can be eliminated. The more strongly doped area above referred to preferably tapers wedge-shaped under the other electrode and is produced by means of implantation, whereby the field oxide and the electrode, whose edges are beveled, are used as the implantation mask.