High-Field Positive-Charge Generation and its Relation to Breakdown in a-SiO2

Weinberg, Z. A.

doi:10.1007/978-1-4613-1031-0_55

Cited by 7 publications

(4 citation statements)

References 110 publications

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“…Moreover, we have found evidence that the driving force for the defect diffusion is the concentration gradient of defect states, accelerated by the inelastic energy input from the applied bias. This result is consistent with the diffusing 'neutral species' proposed by Weinberg in breakdown models for thicker oxides [37].…”

Section: Thicker Oxidessupporting

confidence: 92%

Defect dynamics and wear-out in thin silicon oxides

Farmer

Buhrman

1989

Semicond. Sci. Technol.

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We describe the results of a study of discrete, low-frequency fluctuations in the current through very thin insulator (-20 A), small-area (1-2500pm2) metal-oxide-semiconductor tunnel diodes. Our findings suggest that the discrete nature of the fluctuations arises from the activated transitions of oxide defects, either localised or extended, between a number of accessible metastable configurations, each of which has associated with it a different net trapped charge. Inelastic interactions between the fluctuating defects and the diode tunnel current can result in random energy input to the defects, which can effectively heat them above the bulk oxide temperature. At sufficiently high device biases, these interactions, coupled with interactions between the defects themselves, are strong enough that they can result in the creation of additional oxide defects, and t h u s lead to the gradual wear-out or deterioration of the oxide. A study of the complex fluctuations which arise during thin oxide wear-out and their effects on diode characteristics reveals that after an initial period of Si-SiO, interface defect creation, the oxide wear-out proceeds by the diffusion of defects into the oxide. These moving defects appear to be closely associated with hole traps in the oxide. A number of the characteristics of very thin oxide wear-out can also be seen or inferred in measurements on thicker oxides, suggesting that the studies of very thin oxide diodes are providing a particularly detailed picture of the early stages of trap state formation, wear-out and breakdown in tunnel oxides in general.

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Section: Thicker Oxidessupporting

confidence: 92%

Defect dynamics and wear-out in thin silicon oxides

Farmer

Buhrman

1989

Semicond. Sci. Technol.

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“…This model derived considerable support from a comprehensive theoretical treatment of anode hole injection by surface plasmon excitations, decaying into electron-hole pairs in the silicon gate [62], [63], and experimental data showing the expected dependence on anode material [62], [64]. The original concept was a variant of earlier models [3], [4], [6] postulating a positive feedback mechanism for current runaway, caused by the field-enhancement due to the trapped holes. The main experimental evidence in support of this was a constant value of the hole fluence to breakdown as a function of oxide field [60] C/cm , where the injected hole flux is obtained from the substrate hole current using n-FETs biased in inversion, although it was later shown that decreases for less than about 6 nm [61] and that the constancy of does not hold at temperatures below 300 K [65].…”

Section: Physical Models For Defect Generationmentioning

confidence: 89%

“…The characteristic life is the 63.2th percentile, and is called the slope parameter or Weibull slope. Plotting (6) against yields a straight line with slope (see Fig. 16).…”

Section: Althoughmentioning

confidence: 99%

“…The reliability of SiO , i.e., the ability of a thin film of this material to retain its insulating properties while subjected to high electric fields for many years, has always been an important issue and has been the subject of numerous publications over the last 35 years [2]- [6], since the realization that SiO could be used as an insulating and passivating layer in silicon-based transistors [7], [8]. Oxide reliability and the experimental methods for accelerated testing have been the subject of earlier review papers [9]- [18].…”

Section: Introductionmentioning

confidence: 99%

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Physical and predictive models of ultrathin oxide reliability in CMOS devices and circuits

Stathis

2001

IEEE Trans. Device Mater. Relib.

163

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Abstract-The microelectronics industry owes its considerable success largely to the existence of the thermal oxide of silicon. However, recently there is concern that the reliability of ultra-thin dielectrics will limit further scaling to slightly thinner than 2 nm. This paper will review the physics and statistics of dielectric wearout and breakdown in ultrathin SiO 2 -based gate dielectrics. Electrons or holes tunneling through the gate oxide generate defects until a critical density is reached and the oxide breaks down. The critical defect density is explained by the formation of a percolation path of defects across the oxide. Only 1% of these paths ultimately lead to destructive breakdown, and the microscopic nature of these defects is not known. The rate of defect generation decreases approximately exponentially with supply voltage, below a threshold voltage of about 5 V for hot electron-induced hydrogen release. However, the tunnel current also increases exponentially with decreasing oxide thickness, leading to a decreasing time-to-breakdown and a diminishing margin for reliability as device dimensions are scaled. Estimating the reliability of the dielectric requires an extrapolation from the measurement conditions (e.g., higher voltage) to operation conditions. Because of the diminished reliability margin, it has become imperative to try to reduce the error in this extrapolation.Long-term ( 1 year) stress experiments are now being used to measure the wearout and breakdown of ultrathin ( 2 nm) dielectric films as close as possible to operating conditions. These measurements have revealed the details of the voltage dependence of the defect generation rate and critical defect density, allowing better modeling of the voltage dependence of the time-to-breakdown. Such measurements are used to guide the technology development prior to the manufacturing stage. We then discuss the nature of the electrical conduction through a breakdown spot and the effect of the oxide breakdown on device and circuit performance. In some cases, an oxide breakdown does not lead to immediate circuit failure, so more research is needed in order to develop a quantitative methodology for predicting the reliability of circuits.

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Dielectric breakdown and Poole–Frenkel field saturation in silicon oxynitride thin films

Habermehl

Apodaca

2005

Applied Physics Letters

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Dielectric breakdown is studied in silicon oxynitride thin films varying in composition from SiN1.33 to SiO0.60N0.93. The films are observed to exhibit Poole–Frenkel emission as the dominant charge transport mechanism, with a compositionally dependent ionization potential ranging from 1.22 to 1.51 eV. The barrier lowering energy at the point of dielectric breakdown is independently determined to be likewise compositionally dependent, with the energies correlated to within ∼2kT of the ionization potential. Field saturation-induced trap ionization is discussed as a means to negate carrier scattering from bulk traps as an impediment to impact ionization and dielectric breakdown.

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High-Field Positive-Charge Generation and its Relation to Breakdown in a-SiO2

Cited by 7 publications

References 110 publications

Defect dynamics and wear-out in thin silicon oxides

Defect dynamics and wear-out in thin silicon oxides

Physical and predictive models of ultrathin oxide reliability in CMOS devices and circuits

Dielectric breakdown and Poole–Frenkel field saturation in silicon oxynitride thin films

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