Subthreshold current of dual-gate MOSFET´s

The subthreshold conduction in dual-gate MOS transistors is investigated. The subthreshold current is calculated both in the long-channel case and the short-channel case by means of simple models. Good agreement is found between theory and experimental results obtained through measurements on overlapping-gate n-channel devices. As an application of the subthreshold current analysis, the low-frequency transfer inefficiency in bucket-brigade devices (BBD´s) is evaluated. The theoretical result agrees well with measurements carried out on p-channel nonoverlapping-gate devices.