Extraction of the slow oxide trap concentration profiles in MOS transistors using the charge pumping technique

It is shown that the charge pumping (CP) technique is a very reliable method for the study of the slow traps in the oxide of metal-oxide-semiconductor (MOS) transistors. The trap concentration is obtained from the variation of the gate pulse frequency, the other measurement parameters being kept constant. The concentrations obtained on virgin devices are in agreement with those measured on state-of-the-art MOS transistors using noise measurements. On virgin and stressed devices, they also agree with those measured using a recently proposed drain-current transient method. The concentration profiles show an increase of the trap density near the oxide semiconductor interface.