Four-phase charge-coupled device having an oversized electrode

Claim 1

A semiconductor device comprising a four-phase charge-coupled device having a semiconductor body with a major surface, which comprises a reading stage and a row of electrodes adjacent said surface to which clock voltages can be applied for storing and transferring electrical charge packets, which electrodes are arranged in groups of four, the first electrode of each group being connected to a first clock line, the second electrode being connected to a second clock line, the third electrode being connected to a third clock line, and the fourth electrode being connected to a fourth clock line, the last electrode of the row being connected to a separate connection and being provided adjacent said reading stage, means for applying four-phase clock voltages having wave forms such that, during operation, a potential well is induced in the semiconductor body which extends below at least two neighboring electrodes so that the size of the maximum charge packet which can be stored and transported is determined by the area of two adjacent electrodes, the capacitance of said reading stage being sufficiently large to store this maximum charge packet, the penultimate electrode before the reading stage being at least twice the area of each of the electrodes before it and forming with the underlying part of the semiconductor body a capacitance which is also sufficiently high to store said maximum charge packet, said penultimate electrode being connected to one of said clock lines, and means for applying a voltage to said last electrode of the row such that below the last electrode a potential barrier is induced which causes each charge packet which arrives below the penultimate electrode to be stored only below this penultimate electrode during a selected period before being transferred to the reading stage.