Frequency dependent charge pumping (FD-CP) has emerged as a popular technique for studying the spatial and energetic distribution of defect centers in advanced high-k gate stacks. However, conflicting interpretations of the charge pumping frequency - defect depth relationship has led to controversial and inconsistent findings between various groups. A key assumption is that most, if not all, bulk defect trapping/detrapping contributes to the charge pumping current. In this study, we show, experimentally using two independent measurements, that there is a large discrepancy between the total amount of bulk defect trapping/detrapping that occurs and the actual charge pumping contribution due to these defects. We argue that the charge pumping current due to bulk defects depends heavily upon the specific device geometry/technology, the minority carrier lifetime, and FD-CPs general inability to function as a defect profiling tool.
Citation: IEEE Transactions on Electron Devices
Pub Type: Journals