Charge-coupled structures with self-aligned submicron gaps

A technique for fabricating charge-coupled devices with submicron gaps is described. The method relies on a "shadowing" effect produced by oblique deposition of the metal in an otherwise standard vacuum evaporation process. The biggest advantage of the technique is its extreme simplicity, particularly for one-dimensional CCD structures. The feasibility of the technique has been demonstrated for two-and three-phase devices; the two-phase structure was a 32-bit shift register which has been operated at up to 10 MHz. With some additional processing, the technique can be used to make bidirectional CCD arrays as required in area imagers and serpentine shift registers.