A Single Pulse Charge Pumping Technique for Fast Measurements of Interface States

Characterizing interface states is a key task, and it typically takes seconds when conventional techniques, such as charge pumping (CP), are used. The stress-induced degradation can recover substantially during this time, and there is a need to improve the measurement speed. The central task of this work is to reduce the measurement time for interface states from seconds to microseconds to minimize the recovery. A fast single pulse CP (SPCP) technique is developed. By exploring the differences in the transient currents corresponding to the two edges of the gate pulse, the net charges pumped into devices can be obtained, and their saturation level is used to evaluate interface states. Unlike the conventional CP (CCP) method, the contribution of currents during the plateaus of gate pulse is excluded for SPCP, making it less vulnerable to the interferences of gate leakage and defects within dielectrics. For the first time, the SPCP allows the recovery of interface states being monitored with a time resolution in microseconds. The results show that the recovery of stress-induced interface states is substantial within 100 μs, which would be missed if the CCP were used.