A novel floating-gate method for measurement of ultra-low hole and electron gate currents in MOS transistors

A new method for measurement of ultra-low gate currents in MOS transistors is presented. It is based on a novel coupled floating-gate transistor (CFGT) structure, which enables a clear distinction between threshold voltage shifts due to charge accumulated in the floating gate, and shifts due to device degradation. This advantage gives the new method a demonstrated sensitivity of 10-19A. In addition, with this structure it becomes possible to measure the relation between device degradation and the actual amount of charge injected to the gate. The method is demonstrated by measurements of hole and electron currents in NMOSFET's.