AC analysis of defect cross sections using non-radiative MPA quantum model

Abstract

Abstract-A multiphonon-assisted model included in a PoissonSchroedinger solver has been applied for the calculation of the capture/emission trapping rates of Si/SiO 2 interface defects and their dependence with respect to the trap energy and depth in the oxide. The accurate trap cross-sections extracted with this approach permit compact modeling engineers to evaluate the accuracy of constant cross-section models. The model has been applied to extract the trap concentration and frequency response, comparing AC simulations with measurements.

Modeling Stressed MOS Oxides Using a Multiphonon-Assisted Quantum Approach—Part I: Impedance Analysis

“…The importance of this quantity relies on its direct relation with the cutoff frequency of the MOS admittances, as clearly shown in Section III-A and [26].…”

“…Multifrequency CV [14], [15], [18], deep-level transient spectroscopy [20], [21], trap-assisted tunneling (TAT) [3], [22], and multifrequency charge pumping [23]- [25] experiences have been analyzed to extract the spatial and energetic distribution of defects. However, the models adopted in the aforementioned extractions can lead to major approximations in the estimation of the total trap density and incorrect temperature dependence [26]. Indeed, as pointed out in [27], the standard extension of the SRH recombination theory essentially predicts a correlation between the time constants and the depthwise position, which is not experimentally verified.…”

Modeling Stressed MOS Oxides Using a Multiphonon-Assisted Quantum Approach—Part II: Transient Effects

“…7): The energy dependence of the pumped region on the trap energy is reduced, and thus, a large portion of the energy gap is pumped. However, in this case, the probed regions cannot be derived from the flux contributions using (5), since this would conduct to the incorrect interpretation concluding that fluxes near E Si C and E Si V dominate over the fluxes at midgap [14]. The extension of f CP in oxide depth and energy strongly varies with the pulse characteristics (swing, frequency, lowbase bias, .…”

“…The equilibrium front propagates from the two Si band edges as charge exchange driven by the C/E time constants continues [21]. When decreasing the applied voltage, e − are emitted toward the Si conduction band and traps at the midgap capture h + from the valence band.…”

“…These values have been used throughout this study, but the dependence of the ac characteristics on the Huang-Rhys factor S has been also investigated, varying its value from 0.1 to 50 and noticing a significant variation of the intrinsic trap frequency [21]. The calculation and measurement of this parameter and of its field dependence is still under debate; literature studies performed on bulk materials reported a wide range of values from several decades down to 1 [12], [27].…”