An evaluation of submicrometer potential barriers using charge-transfer devices

A technique is described to investigate the charge dynamics over submicrometer potential barriers using transfer efficiency measurements in charge-transfer devices when they are operating near to their theoretical minimum clock voltages. In this range of operation it is shown that the efficiency of the device is limited by undesirable potential discontinuities in the interelectrode gaps which greatly depend on the means of fabrication. Using a simple analysis of time-dependent subthreshold conduction it is shown how to determine the parameters of the barrier and to understand its dependence on the electrode potentials. The use of this technique to determine the barrier parameters is demonstrated using measurements of Qlossversus temperature, frequency, and voltage. It is also shown how to use the technique to distinguish between barrier losses and interface state losses.