The surface potential variation in the interelectrode gaps of GaAs cermet-gate charge-coupled devices

Abstract A transmission line model for the cermet/GaAs junction is proposed and is used to investigate the variation of the surface potential along the interelectrode gaps of a GaAs cermet gate charge-coupled device (CMCCD). The surface potential variation is shown to be frequency dependent but always monotonic. This is desirable for minimizing the formation of energy troughs which cause poor charge transfer. The performance of a 64-pixel, 4-phase GaAs CMCCD was compared to that of a device lacking the cermet gates. The former device exhibited superior performance at 100 MHz operation. This is attributed to the control of the surface potential in the interelectrode gaps provided by the cermet gates.