Hole injection SiO/sub 2/ breakdown model for very low voltage lifetime extrapolation
TL;DR: In this paper, a model for silicon dioxide breakdown characterization, valid for a thickness range between 25 /spl Aring/ and 130 /spl Ring/, is presented, which provides a method for predicting dielectric lifetime for reduced power supply voltages and aggressively scaled oxide thicknesses.
Abstract: In this paper, we present a model for silicon dioxide breakdown characterization, valid for a thickness range between 25 /spl Aring/ and 130 /spl Aring/, which provides a method for predicting dielectric lifetime for reduced power supply voltages and aggressively scaled oxide thicknesses. This model, based on hole injection from the anode, accurately predicts Q/sub BD/ and t/sub BD/ behavior including a fluence in excess of 10/sup 7/ C/cm/sup 2/ at an oxide voltage of 2.4 V for a 25 /spl Aring/ oxide. Moreover, this model is a refinement of and fully complementary with the well known 1/E model, while offering the ability to predict oxide reliability for low voltages. >
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29 Apr 2003
TL;DR: Channel engineering techniques including retrograde well and halo doping are explained as means to manage short-channel effects for continuous scaling of CMOS devices and different circuit techniques to reduce the leakage power consumption are explored.
Abstract: High leakage current in deep-submicrometer regimes is becoming a significant contributor to power dissipation of CMOS circuits as threshold voltage, channel length, and gate oxide thickness are reduced. Consequently, the identification and modeling of different leakage components is very important for estimation and reduction of leakage power, especially for low-power applications. This paper reviews various transistor intrinsic leakage mechanisms, including weak inversion, drain-induced barrier lowering, gate-induced drain leakage, and gate oxide tunneling. Channel engineering techniques including retrograde well and halo doping are explained as means to manage short-channel effects for continuous scaling of CMOS devices. Finally, the paper explores different circuit techniques to reduce the leakage power consumption.
2,281 citations
Cites background from "Hole injection SiO/sub 2/ breakdown..."
...The FN current equation represents the tunneling through the triangular potential barrier and is valid for , where is the voltage drop across the oxide [30]....
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...direct tunneling is given by [30]...
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...oxide tunneling current exponentially decreases with an increase in the oxide thickness [30]; b) dynamic power consumption, since higher oxide thickness reduces the gate capacitance, which is beneficial for...
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...Hence, the direct tunneling occurs at [30]....
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IBM1
TL;DR: In this article, the key challenges in further scaling of CMOS technology into the nanometer (sub-100 nm) regime in light of fundamental physical effects and practical considerations are discussed, including power supply and threshold voltage, short-channel effect, gate oxide, high-field effects, dopant number fluctuations and interconnect delays.
Abstract: Starting with a brief review on 0.1-/spl mu/m (100 nm) CMOS status, this paper addresses the key challenges in further scaling of CMOS technology into the nanometer (sub-100 nm) regime in light of fundamental physical effects and practical considerations. Among the issues discussed are: lithography, power supply and threshold voltage, short-channel effect, gate oxide, high-field effects, dopant number fluctuations and interconnect delays. The last part of the paper discusses several alternative or unconventional device structures, including silicon-on-insulator (SOI), SiGe MOSFET's, low-temperature CMOS, and double-gate MOSFET's, which may lead to the outermost limits of silicon scaling.
861 citations
Cites background from "Hole injection SiO/sub 2/ breakdown..."
...There have been many publications that have demonstrated, both from a theoretical perspective as well as from measured results, that as the dielectric is thinned for a given applied bias, the charge required for dielectric breakdown increases rapidly [25]....
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TL;DR: In this paper, the authors summarized recent progress and current scientific understanding of ultrathin (<4 nm) SiO2 and Si-O-N (silicon oxynitride) gate dielectrics on Si-based devices.
Abstract: The outstanding properties of SiO2, which include high resistivity, excellent dielectric strength, a large band gap, a high melting point, and a native, low defect density interface with Si, are in large part responsible for enabling the microelectronics revolution. The Si/SiO2 interface, which forms the heart of the modern metal–oxide–semiconductor field effect transistor, the building block of the integrated circuit, is arguably the worlds most economically and technologically important materials interface. This article summarizes recent progress and current scientific understanding of ultrathin (<4 nm) SiO2 and Si–O–N (silicon oxynitride) gate dielectrics on Si based devices. We will emphasize an understanding of the limits of these gate dielectrics, i.e., how their continuously shrinking thickness, dictated by integrated circuit device scaling, results in physical and electrical property changes that impose limits on their usefulness. We observe, in conclusion, that although Si microelectronic devices...
747 citations
TL;DR: In this article, a nanocomposite anodes for the oxidation of water required to produce renewable fuels is presented. But the anodes are not suitable for large-scale electrochemical energy production with minimal global warming gas emission.
Abstract: A leading approach for large-scale electrochemical energy production with minimal global-warming gas emission is to use a renewable source of electricity, such as solar energy, to oxidize water, providing the abundant source of electrons needed in fuel synthesis. We report corrosion-resistant, nanocomposite anodes for the oxidation of water required to produce renewable fuels. Silicon, an earth-abundant element and an efficient photovoltaic material, is protected by atomic layer deposition (ALD) of a highly uniform, 2 nm thick layer of titanium dioxide (TiO(2)) and then coated with an optically transmitting layer of a known catalyst (3 nm iridium). Photoelectrochemical water oxidation was observed to occur below the reversible potential whereas dark electrochemical water oxidation was found to have low-to-moderate overpotentials at all pH values, resulting in an inferred photovoltage of ~550 mV. Water oxidation is sustained at these anodes for many hours in harsh pH and oxidative environments whereas comparable silicon anodes without the TiO(2) coating quickly fail. The desirable electrochemical efficiency and corrosion resistance of these anodes is made possible by the low electron-tunnelling resistance (<0.006 Ω cm(2) for p(+)-Si) and uniform thickness of atomic-layer deposited TiO(2).
672 citations
TL;DR: In this paper, it was concluded that the generation of neutral electron traps in thin oxides is the dominant cause of leakage currents introduced in the low-field, direct-tunneling regime of thin oxide during high-field stress.
Abstract: Leakage currents introduced in the low‐field, direct‐tunneling regime of thin oxides during high‐field stress are related to defects produced by hot‐electron transport in the oxide layer. From these studies, it is concluded that the ‘‘generation’’ of neutral electron traps in thin oxides is the dominant cause of this phenomenon. Other mechanisms due to anode hole injection or oxide nonuniformities are shown to be unrealistic for producing these currents. Exposure of thin oxides to atomic hydrogen from a remote plasma is shown to cause leakage currents similar to those observed after high‐field stress, supporting the conclusion that these currents are related to hydrogen‐induced defects.
524 citations
References
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TL;DR: In this article, the relative effective mass in the forbidden energy gap was found to be about 0.4, which is lower by a factor of five to ten than the expected values, probably due to trapping effects.
Abstract: Electronic conduction in thermally grown SiO2 has been shown to be limited by Fowler‐Nordheim emission, i.e., tunneling of electrons from the vicinity of the electrode Fermi level through the forbidden energy gap into the conduction band of the oxide. Fowler‐Nordheim characteristics have been observed over more than five decades of current for emission from Si, Al, and Mg. If previously measured values of the barrier heights are used, the slopes of the Fowler‐Nordheim characteristics (log J/E2 vs 1/E) imply values of the relative effective mass in the forbidden band of about 0.4. These values take into account corrections for image‐force barrier lowering and for temperature effects. The absolute values of the currents are lower by a factor of five to ten than the theoretically expected values, probably due to trapping effects. The temperature dependence of the current was found to follow the theoretical curve from 80°–420°K. However, an inconsistent relative effective mass of about 0.95 had to be assumed....
1,640 citations
TL;DR: In this article, a characteristic interface trap was observed in a hole trapping experiment when electrons were captured by trapped holes injected by an avalanche in the silicon, which could be explained by the generation of new electronic states through relaxation of strained bonds which were proposed to be the origin of hole traps.
Abstract: A characteristic interface trap was observed in a hole trapping experiment when electrons were captured by trapped holes injected by an avalanche in the silicon. The observations could be explained by the generation of new electronic states through relaxation of strained bonds which were proposed to be the origin of hole traps. The result is either a weak bond in the network or two dangling bonds with no net charge. The weak bond or dangling bonds give rise to neutral traps in the bulk and interface traps at the interface of the oxide. The presence of interface traps for such defects at the interface is predicted by theoretical calculations.
454 citations
TL;DR: In this article, a quantitative model for oxide breakdown based on impact ionization and hole trapping at the cathode is presented and shown to agree well with the experimental J - t and time-to-breakdown, (t BD ) results.
Abstract: The breakdown of thin oxides (7.9-32 nm) subjected to high-field current injection is investigated in this study. The physical mechanism of breakdown is found to be localized field enhancement at the cathode interface due to hole trapping. The source of this hole trapping is believed to be impact ionization in the SiO 2 . A quantitative model for oxide breakdown based on impact ionization and hole trapping at the cathode is presented and shown to agree well with the experimental J - t and time-to-breakdown, (t BD ) results. We observe that log t BD varies linearly with 1/ E rather than with E as commonly assumed. The field acceleration factor, i.e., the slope of the log t BD versus 1/ E plot, is approximately 140 decades per centimeter per megavolt for the 7.9 nm oxide, with approximately 25 percent of this coming from the field dependence of the impact ionization coefficient and the remainder from the Fowler-Nordheim current dependence on 1/ E . Based on this model, oxide wearout performance might be improved by process changes that reduce interface hole trapping, such as radiation-hard processing, in addition to the reduction of particulate contamination and crystal defects.
426 citations
TL;DR: In this paper, the intrinsic breakdown mechanism in films of thermal SiO2 in the thickness range 30-300 A was studied and it was determined that high-field and high electron injection current conditions existing in the films just prior to breakdown result in the generation of a very high density of defects which behave electrically as stable electron traps.
Abstract: A novel technique is described which was used to study the intrinsic breakdown mechanism in films of thermal SiO2 in the thickness range 30–300 A. It was determined that high‐field and high electron injection current conditions existing in the films just prior to breakdown result in the generation of a very high density of defects which behave electrically as stable electron traps. These traps are most likely generated close to the injecting electrode. The internal field in the oxide due to trapped electrons can approach 3×107 V/cm which appears to be the maximum field strength which Si‐O bonding can withstand. At all temperatures between 77 and 393 °K, the breakdown mechanism is intimately related to the rate of generation of the electron traps. No evidence was found to support the impact ionization breakdown model. The technique is also described as a tool for yield measurements, with important implications for long‐term reliability of MOS IC’s.
420 citations
TL;DR: In this article, a technique of predicting the lifetime of an oxide to different voltages, different oxide areas, and different temperatures is presented using the defect density model in which defects are modeled as effective oxide thinning, many reliability parameters such as yield, failure rate and screen time/screen yield can be predicted.
Abstract: A technique of predicting the lifetime of an oxide to different voltages, different oxide areas, and different temperatures is presented. Using the defect density model in which defects are modeled as effective oxide thinning, many reliability parameters such as yield, failure rate, and screen time/screen yield can be predicted. This modeling procedure is applicable to both wafer-level and long-term reliability tests. Process improvements including defect gettering and alternative dielectrics such as chemical-vapor-deposited oxides are evaluated in the format of defect density as a function of effective oxide thinning. >
367 citations