A comprehensive model for oxide degradation
Introduction
Scaling of CMOS devices, as specified by the ITRS, makes understanding of process involved in oxide damage of crucial importance for getting better performances.
For this reason, a lot of studies have been devoted toward the physics of oxide degradation. However, the debate on which is the main damage responsible (the electric field [1] or the carrier energy [2]) is still open.
Here, we propose two analytical models, physically based, able to predict stress induced leakage current (SILC) in thin and ultra-thin (tOX < 4 nm approximately) oxides.
Section snippets
Degradation models
In this section, two analytical models describing trap kinetics in thin and ultra-thin SiO2 films under DC electrical stress are presented. In both cases, defect creation is thought to be ruled by hot carrier energy release, which causes SiH bond breaking [2]. However, the mechanism of energy release changes with oxide thickness. This difference is taken into account writing two different rate equations for thin and ultra-thin oxides degradation kinetics.
Transient of trap kinetics
Degradation models presented in Section 2 are valid under steady state stress conditions and cannot take into account the transient behaviour of trap kinetics. This transient can be related to a phenomenological picture based on the hypothesis that the defect creation is a two-step process [6]. During an electrical stress, at first defect precursors are formed in the oxide, which represent unstable energetic states of the network. They are converted in stable traps if the external perturbation
Conclusions
In this work we have presented a comprehensive, physically based, analytical model for both thin and ultra-thin oxides degradation kinetics, which have been experimentally validated. Furthermore, starting from the microscopic theory of defect precursors, we have demonstrated that the pulsed stress with an appropriate waveform duty cycle can strongly reduce oxide damage respect to DC case.
References (8)
- et al.
Underlying physics of thermochemical E model in describing low field time dependent dielectric breakdown in SiO2 thin films
J Appl Phys
(1998) Electron energy dependence of metal–oxide–semiconductor degradation
Appl Phys Lett
(1999)Degradation kinetics of stressed oxides
Appl Phys Lett
(2001)- et al.
Modeling and simulation of stress induced leakage current in ultrathin SiO2 films
IEEE Trans Electron Devices
(1998)
Cited by (2)
3D KMC simulations of crater growth during the reduction of oxide nanoislands on metal surfaces
2011, Surface ScienceCitation Excerpt :Oxide reduction is also frequently involved in hydrometallurgical processes for recovering pure metals from their native oxides [8]. Other processes of oxide reduction include fabrication of electronic devices, magnetic memory components and active/passive solar materials systems [9–14]. Traditionally, the reduction process of metal oxides has been described using phenomenological kinetic models.
Reduction of CuO nanowires confined by a nano test tube
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