Zero Loss Transfer Across Gaps in a CCD

Abstract

When a charge-coupled device is made with a single layer of metallization, adjacent electrodes must be placed several micrometers apart. As a result there may be some difficulty in moving the charge from one electrode to another. In this paper it will be shown that, for any substrate material, there is a wide range of interface charge for which complete transfer can be achieved regardless of electrode separation. It will further be shown that for a p-substrate with a doping of less than 1016/cm3, the natural charge found in a good quality thermally grown layer of SiO2 is always of the appropriate sign and magnitude to ensure complete transfer. Therefore, for simple fabrication of a CCD with one layer of metal, this substrate material is the appropriate choice.