Observation and mechanism explanation of the parasitic charge pumping current

A parasitic charge pumping current (I_PCP) is observed and extracted properly. While charge pumping current after correction (I _COCP) contributes to threshold voltage shift, this transient I _PCP does not contribute and should be extracted from CP current (I_CP). This I_PCP is shown to be unable to be extracted by conventional low-high multi-frequency CP method (LHMF). It could only be extracted effectively enough by a high-high multi-frequency charge pumping (CP) method (HHMF). In HHMF, a high frequency is employed to measure I_PCP; while in LHMF, a low frequency is used to measure the current out of I _COCP. Without eliminating I_PCP, large noise tail in LHMF method distorts the shape of I_COCP curve and even masks maximum I_COCP current (I_CPmax). This is because I_PCP is due to transient charge-trapping and -detrapping. Therefore, I_PCP is frequency dependent and its value can be obtained sufficiently only when frequency is no lower than 1 MHz. Regarding both the value of I_CPmax and the shaping of I_COCP curve, HHMF is more recommended for CMOS devices with SiON and high-κ dielectrics with high transient trap density.