A model to study the effect of selective anodic oxidation on ultrathin gate oxides
TL;DR: In this paper, the effect of selective anodic oxidation on ultrathin (22-31 /spl Aring/) silicon dioxide grown at different temperatures ranging from 600/spl deg/C to 875/spl Deg/C, on both p-and n-type substrates was studied.
Abstract: We have studied the effect of selective anodic oxidation on ultrathin (22-31 /spl Aring/) silicon dioxide grown at different temperatures ranging from 600/spl deg/C to 875/spl deg/C, on both p- and n-type substrates. A model based on the concept of filling of pinholes by selective anodic oxidation is presented to quantitatively explain the reduction in the gate leakage current of the MOS capacitors after selective anodic oxidation.
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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. >
530 citations
"A model to study the effect of sele..." refers methods in this paper
...Now, the leakagecurrentdensity canbe modeled using an expression for a direct tunneling current [7] given by...
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TL;DR: In this paper, the authors show that after tunnel injection of 1017 −5×1018 electrons/cm2, the barrier undergoes significant degradation leading to enhanced tunneling conductance, with reproducible behavior observed among different samples.
Abstract: Thin‐oxide (40–50 A) metal oxide semiconductor (MOS) structures are shown to exhibit, prior to large levels of electron tunnel injection, the near‐ideal behavior predicted for a uniform trapezoidal barrier with thick‐oxide properties. The oscillatory field dependence due to electron‐wave interference at the Si/SiO2 interface indicates an abrupt, one‐monolayer barrier transition (∼2.5 A) consistent with earlier work. After tunnel injection of 1017 –5×1018 electrons/cm2, the barrier undergoes significant degradation leading to enhanced tunneling conductance, with reproducible behavior observed among different samples. This effect is consistent with the generation of positive states in the region of the oxide near the Si/SiO2 interface (<20 A), where the tunneling electrons emerge into the oxide conduction band. Densities of positive‐charge and interface‐state buildup are also observed from capacitance‐voltage (C‐V) measurements and are found to be consistent with the observed tunneling dependence on positiv...
271 citations
"A model to study the effect of sele..." refers result in this paper
...415 corresponding to oxidation temperature of 875 C agrees very well with the values reported previously for ultrathin oxides with minimum defect density [8], [9]....
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TL;DR: In this article, an effective mass for the tunneling electron in the SiO2 layer was extracted from the thickness dependence of the direct tunneling current between an applied voltage of 0 and 2 V, a bias range that has not been previously explored.
Abstract: Electron transport in ultrathin (tox<40 A) Al/SiO2/n−Si structures is dominated by direct tunneling of electrons across the SiO2 barrier. By analyzing the tunneling currents as a function of the SiO2 layer thickness for a comprehensive set of otherwise identical samples, we are able to extract an effective mass for the tunneling electron in the SiO2 layer. Oxide films 16–35 A thick were thermally grown in situ in a dry oxygen ambient. The oxide thicknesses were determined by capacitance–voltage measurements and by spectroscopic ellipsometry. The tunneling effective mass was extracted from the thickness dependence of the direct tunneling current between an applied voltage of 0 and 2 V, a bias range that has not been previously explored. Employing both a parabolic and a nonparabolic assumption of the E−κ relationship in the oxide forbidden gap, we found the SiO2 electron mass to be mP*=0.30±0.02me, and mNP*=0.41±0.01me, respectively, independent of bias. Because this method is based on a large sample set, t...
259 citations
"A model to study the effect of sele..." refers result in this paper
...415 corresponding to oxidation temperature of 875 C agrees very well with the values reported previously for ultrathin oxides with minimum defect density [8], [9]....
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IBM1
TL;DR: In this article, the rate of formation of very thin films thermally grown on [111] and [100] oriented silicon wafers was studied using ellipsometry to measure oxide thickness.
Abstract: The rate of formation of very thin films thermally grown on [111] and [100] oriented silicon wafers was studied using ellipsometry to measure oxide thickness. Film thicknesses from 10–300Aa were obtained by varying oxidation time, oxidation temperature (700°–1000°C), and oxygen concentration in O2‐N2 mixtures at 1 atm total pressure. The applicability of ellipsometry for such a study is discussed. Reproducibility of oxide films grown to thicknesses of 20–30Aa was approx. ±1.0Aa. Under otherwise equal conditions the oxide thickness grown differs for [100] and [111] oriented wafers. The pressure and temperature dependence of the linear rate constant, klin, show that the growth reaction is more complicated than was suggested earlier. In particular, a different pressure dependence for the two substrate orientations used indicates that several oxygen species participate in the rate determining steps.
96 citations
"A model to study the effect of sele..." refers background in this paper
...With lower growth temperature it is possible to obtain better control over the thickness of silicon dioxide [1], [2] but at the cost ofmore number of pinholes and defects in the oxide, resulting in increased leakage and unreliable performance [3]....
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TL;DR: In this article, the formation of voids on the thermally grown (650 °C) ultrathin (∼1 nm) silicon oxide films on the Si(100) surface was investigated by using ultrahigh vacuum scanning tunneling microscopy.
Abstract: The formation of voids on the thermally grown (650 °C) ultrathin (∼1 nm) silicon oxide films on the Si(100) surface was investigated by using ultrahigh vacuum scanning tunneling microscopy. Voids form randomly on the ultrathin oxide film upon thermal annealing at 750 °C. In contrast to void formation observed on thicker (>5 nm) thermal silicon oxide films and that observed on ultrathin (∼1 nm) oxide films formed by room temperature O2 adsorption, the number of voids increases during annealing. We find that Si monomer creation and SiO production compete kinetically in the void formation process.
70 citations
"A model to study the effect of sele..." refers background in this paper
...With lower growth temperature it is possible to obtain better control over the thickness of silicon dioxide [1], [2] but at the cost ofmore number of pinholes and defects in the oxide, resulting in increased leakage and unreliable performance [3]....
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