Bulk transport charge-coupled device with linear input characteristic

Abstract

A charge-coupled device includes a semiconductor body (3) having a semiconductor layer (3) of a first conductivity type adjoining a surface and means for depleting the semiconductor layer throughout its thickness while avoiding breakdown. A sequence (row) of transport electrodes are provided on the surface above the semiconductor layer and are separated by a blocking (isolating) layer from the semiconductor layer and are connected to a clock voltage source to form in the semiconductor layer mutually separated potential wells for storing and transporting information-carrying charge packets. An input stage (I) has a supply zone for supplying majority charge carriers and an input electrode. The input electrode is located between the supply zone and the transport electrodes and is separated by the isolating layer from the semiconductor surface. An input signal source is provided along with means for forming under the input electrode a potential well whose minimum is located closer to the surface than are the potential wells under the transport electrodes. A dopant of the second opposite conductivity type is introduced between the supply zone and the transport electrodes in so that the net doping of the first conductivity type in the part (I) of the semiconductor layer between the supply zone and the transport electrodes is lower than in the remaining part of the layer. Preferably, the width of the electrodes of the input stage (I) is chosen so that the transport capacity of these electrodes is practically equal to that of the transport electrodes.