TRANSIENT CLOCK VOLTAGE AND HEATING EFFECTS IN HIGH-SPEED RESISTIVE-GATE CHARGE-COUPLED-DEVICES (RGCCDS)

This work investigates the transient clock voltage and heating effects in high-speed GaAs resistive-gate charge-coupled devices (RGCCDs). Th e resistivity of the resistive-gate (cermet) was chosen as a variable parameter. The transient voltage delays were computed using a circuit model (similar to the transmission line model reported by Lenoble et a l. 1990 a). These were combined with the charge transport times comput ed using a one-dimensional analytical model (Pennathur and Kwok 1992) and estimations were made on the peak operating frequencies. The low f requency limits of the device were computed by analysing the heating e ffect of the cermet layer on the leakage currents and the resulting th ermally-generated carriers. It was observed that there were conflictin g requirements on the cermet resistivity when both the speed and the t ransfer inefficiency of the RGCCDs had to be simultaneously optimized. The decision on the choice of the cermet resistivity largely depends on a trade-off in the device performance.