Capture/emission processes of carriers in heterointerface traps observed in the transient charge-pumping characteristics of SiGe/Si-hetero-channel pMOSFETs

Transient phenomena related to carrier capture/emission processes in interface traps were observed in the the charge pumping (CP) characteristics of SiGe/Si hetero-channel pMOSFETs, i.e., the CP characteristics were found to depend on the on/off time of the gate pulse. From these observations, time constants for the processes both in SiGe/Si heterointerface traps and in gate-oxide interface traps were derived. The time constant is considered to depend on the energy level of the interface traps that are present over a wide range within the energy gap. Therefore, these phenomena provide an interesting way of evaluating the discrete energy levels of interface traps in nanometer-scale devices containing only a few traps.