Document Type and Number:
Japanese Patent JPS5026911
Kind Code:
B1
Abstract:
1369606 Charge coupled devices INTERNATIONAL BUSINESS MACHINES CORP 1 Nov 1971 [4 Dec 1970] 50605/71 Heading H1K A charge coupled device comprises a semiconductor body with an electrode structure so designed that a charge zone can be stepped through the body by impressing only two time varying depletion region creating voltages on the electrodes. In the structure shown, Fig. 1, holes injected into the N-type silicon body 10 at 28 from a P-type zone or point contact with an associated gate 29, are stepped along a serpentine path defined between the parallel ridges 18a-18g of an oxide insulating layer by oppositely phased overlapping negative voltage pulses applied to interdigitated electrodes 20, 21. Along the base of each of channels 15a-15f the oxide has alternately thick and thin portions with each digit of each electrode extending over an adjacent pair of thick and thin portions. The locations of the thick and thin portions are reversed in adjacent channels so that the asymmetrical potential wells formed under each electrode digit on application of pulses thereto ensure transfer of the holes in opposite directions in the adjacent channels. In alternative forms the insulation in each channel has a sawtooth section or is of uniform thickness but with alternate sections of different dielectric constant. The preferred structure shown is made by forming a thick layer of oxide overall and then etching through masks and reforming the oxide in two stages. The electrodes, of aluminium, are then formed by deposition and are provided with contact pads 31-35 of chromium, copper, gold, tin or lead, and quartz is sputtered over the assembly to protect it. Read out is effected via strip electrode 30 to which a voltage higher than that on electrodes 20, 21 is applied, the resulting accumulation of holes beneath it affecting the forward characteristics of a heterojunction or the reverse characteristic of a PN or point contact diode located in the vicinity. A suitable detector circuit is described (Fig. 7, not shown) the output of which may be used to cause remjection of the holes at 28. The device may be associated with a buffer shift register (Fig. 8, not shown). Reference has been directed by the Comptroller to Specification 1,340,620.
Application Number:
JP9457371A
Publication Date:
September 04, 1975
Filing Date:
November 26, 1971
Export Citation:
International Classes:
G11C19/28; H01L29/423; H01L29/768; (IPC1-7): H01L29/78