The notion of optimum for the charge-coupled device (CCD) aims at reaching simultaneously a reduced form of the structure with clock frequencies well defined in order to give excellent performance and a minimum value of applied voltage to ensure good storage with a complete transfer of charges. The various properties of CCD device configurations are investigated by means of a computer model, based on the numerical solution of Poisson's equation which describes the transfer of charges from one cell to another. This numerical model takes into account the recombination-generation phenomenon at the interface Si/SiO 2 described by Shockley-Read-Hall theory. The modelling is used for assessing the influence of geometrical, electrical and technological parameters which the choice is essential in optimum CCD performances.