Ultimate limit for defect generation in ultra-thin silicon dioxide

DiMaria, D. J.; Stathis, James H.

doi:10.1063/1.120299

Cited by 111 publications

(60 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…For voltages below threshold, it was shown [24] that the defect generation rate depends only on the absolute value of the gate voltage , independent of substrate or gate doping or polarity. Recent work using the SILC to measure has given the somewhat surprising result that 2 eV is not a hard threshold [25], [119]. Instead, there is a subthreshold trap generation process that decreases exponentially below 5 V. This is shown in Fig.…”

Section: Defect Generation Ratementioning

confidence: 88%

See 1 more Smart Citation

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

Stathis

2001

IEEE Trans. Device Mater. Relib.

163

View full text Add to dashboard Cite

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.

show abstract

Section: Defect Generation Ratementioning

confidence: 88%

“…[24], [32], [93], [114]- [118]. On the other hand, several groups have reported measurements showing a decrease in as the stress voltage is reduced using 3-5-nm oxides [77], [119]- [121]. This observation could have a significant effect on the reliability projections for such oxides.…”

Section: The Critical Defect Densitymentioning

confidence: 97%

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

Stathis

2001

IEEE Trans. Device Mater. Relib.

163

View full text Add to dashboard Cite

show abstract

“…Recently, it has been reported that was increased for very long stress times [67] and under alternating bias stress [68]. Other reports indicated a decreasing for decreasing stress voltage [35], [69], [70]. More studies are required to understand the exact relationship between electrically measured defects and those that lead to oxide wear-out and eventual breakdown.…”

Section: A the Weibull Distribution And Percolation Theorymentioning

confidence: 99%

“…In the direct tunneling regime, the energy of the tunneling electrons is proportional to the applied gate voltage [35]. When considering a physical process for defect creation in thin oxides it is important to consider the energy required for such a process to occur.…”

Section: Energy and Electron-induced Defect Generationmentioning

confidence: 99%

Ultrathin gate oxide reliability: physical models, statistics, and characterization

Suehle

2002

IEEE Trans. Electron Devices

145

View full text Add to dashboard Cite

Abstract-The present understanding of wear-out and breakdown in ultrathin ( 5 0 nm) SiO 2 gate dielectric films and issues relating to reliability projection are reviewed in this article. Recent evidence supporting a voltage-driven model for defect generation and breakdown, where energetic tunneling electrons induce defect generation and breakdown will be discussed. The concept of a critical number of defects required to cause breakdown and percolation theory will be used to describe the observed statistical failure distributions for ultrathin gate dielectric breakdown. Recent observations of a voltage dependent voltage acceleration parameter and non-Arrhenius temperature dependence will be presented. The current understanding of soft breakdown will be discussed and proposed techniques for detecting breakdown presented. Finally, the implications of soft breakdown on circuit functionality and the applicability of applying current reliability characterization and analysis techniques to project the reliability of future alternative gate dielectrics will be discussed.

show abstract

“…Conventional tests are usually made at the device scale, although it has been shown that breakdown can be a highly localised phenomenon (DiMaria and Stathis 1997). Advances in our ability to explore local properties make possible to gain a deeper understanding of basic mechanisms involved.…”

Section: Introductionmentioning

confidence: 99%

Conductive atomic force microscopy as a tool to reveal high ionising dose effects on ultra thin SiO2/Si structures

Arinero¹,

Touboul²,

Ramonda³

et al. 2012

Appl Nanosci

View full text Add to dashboard Cite

The electrical stress behaviour of non-irradiated and irradiated (2 to 7-nm thick) SiO 2 /Si structures is investigated using conductive-atomic force microscopy. A protocol based on the successive application of two rampedvoltage stresses (RVS) on each test point is performed. The environmental implementation conditions of such an experiment are then investigated. A statistical approach based on the use of Weibull distributions is also adopted. Before irradiation, for the thinnest samples, it is shown evidence of stress-induced trap-assisted tunnelling leading to a high decrease in threshold voltages on the second RVS. After high-dose X-ray irradiations, the first RVS exhibit voltage-shift effects increasing with the oxide film thickness, whereas for the second RVS, no additional effect is observed. The high locality of these measurements, sensitive to a few tens of trapped charges, is therefore demonstrated and constitutes a new step towards a better understanding of oxide degradation mechanisms due to radiation effects.

show abstract

Ultimate limit for defect generation in ultra-thin silicon dioxide

Cited by 111 publications

References 8 publications

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

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

Ultrathin gate oxide reliability: physical models, statistics, and characterization

Conductive atomic force microscopy as a tool to reveal high ionising dose effects on ultra thin SiO2/Si structures

Contact Info

Product

Resources

About