Detailed Analysis of Si-SiO₂ Interface Traps in State-of-the-Art MOSFETs Using Charge Pumping

Abstract

Based on charge pumping (CP) mechanisms, the way Si-SiO2 interface traps interact with the gate CP signal in state-of-the-art MOSFETs with a thick SiO2 gate dielectric is detailed. The consequences that can be deduced or studied from the previous results are presented. This includes the way the interface is probed, the slope of the CP curves and the resulting interface trap density extraction from them. The dependence of CP curves with gate signal frequency and the high frequency limit case are dealt with using simulation. Both are very well accounted for, providing new information on Si-SiO2 interface trap characteristics.

(Invited) On the Modeling of the Charge Pumping Curves

“…The TCD distribution of the interface traps is broader than that measured but more importantly, the fitting reported in (1) was obtained after increasing the oxide trap density, Nto, from 1.2x10 16 eV 1 .cm 3 as measured, to 6.9x10 16 eV 1 .cm 3 . As a result, Nto which contributes to only a few percent to the overall CP current, provides a significant CP current magnitude with regard to that of the interface states and would lead to an unrealistic frequency dependence of the CP curves (24).…”

“…This figure highlights the large signal due to the near oxide traps that results from the concentration introduced with regard to that measured. It would strongly impact the frequency dependence of these curves with regard to experimental data (24). Note also that due to a larger trap cross section for electrons with regard to acceptor traps, the donor response rises at a lower Vg, while due to a larger cross section for holes with regard to donors, the acceptor response falls off at a higher V l bias.…”