On-chip charge pumping method for characterization of interface states of ultra thin gate oxide in nano CMOS technology

For the first time, on-chip charge pumping method is proposed to characterize ultra thin gate oxide for nano-scale CMOSFETs. Designed on-chip charge pumping system can supply 30-500MHz square-type pulse waves to DUT transistor and measured charge pumping current showed no gate tunneling current dependency which can be easily monitored in very thin gate oxide. In addition to the measurement of interface states by fixed-amplitude method, the distribution of interface states in channel region can be easily extracted by fixed-base method using this system. The proposed method is also successfully applied to analyze hot-carrier stress-induced threshold voltage (V_t)-degradation and to evaluate plasma process induced damage in terms of interface trap density