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

Abstract

Abstract-Complementary MOS device electrical performances are considerably affected by the degradation of the oxide layers and Si/SiO 2 interfaces. A general expression for electrically stressed MOS impedance has been derived and applied within the nonradiative multiphonon theory of carrier capture/emission at oxide defects. The capacitance and the conductance of aged MOS field-effect transistor oxides, and their dependences on bias voltage, temperature, and stress conditions have been investigated.

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

“…Traps follow a spatial and energetic distribution N T (x, E T ) in the oxide layer, f T (x, E T , E F , t) = 1/(1 + exp((E T − E F )/k B T )) is the electron trap occupation, the holes (electron, 0018-9383/$31.00 © 2012 IEEE respectively) C/E fluxesΦ C /Φ E (Φ C /Φ E , respectively) have been calculated as in [17] and [18], and g is a charge factor introduced to take into account the defect charging model. The general approach of (1) is required to accurately take into account the out-of-equilibrium conditions of the system.…”

“…It should be pointed out that the attribution of a quasi-Fermi level to a single defect has been only performed in the view of better illustrating the equilibrium steady state condition. Indeed, in part I [17], the dc operating point for the ac analysis has been calculated in quasi-static conditions, neglecting all the large-signal transient effects. After a sufficiently long time, the defects establish a common equilibrium condition with the substrate/gate, and their quasi-Fermi levels equal the one in the carrier reservoirs.…”

“…In part I [17], a multiphonon-assisted impedance model has been described and validated on ac measurements. This study has been performed considering equilibrium conditions for dc and small-signal ac analysis [17], and the region of the dielectric layer characterized with capacitance measurements has been determined.…”

“…This study has been performed considering equilibrium conditions for dc and small-signal ac analysis [17], and the region of the dielectric layer characterized with capacitance measurements has been determined.…”

“…In this paper, the multiphonon-assisted model presented in [17] is applied to the analysis of transient effects on ac characteristics and to the assessment of MFCP measurements for trap dynamics analysis. The proposed model can be adopted to evaluate the accuracy of trap extraction techniques and for the determination of the spatial and energetic distribution of defects.…”