Kinetics of thermal nitridation processes in the study of dopant diffusion mechanisms in silicon

Fahey, P.; Barbuscia, G.P.; Moslehi, Mehrdad M.; Dutton, R.W.

doi:10.1063/1.95909

Cited by 165 publications

(46 citation statements)

References 7 publications

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“…This points to a supersaturation of native point defects established by B diffusion. Additional results on B diffusion in Si isotope structures obtained at different temperatures, on enhanced (retarded) B diffusion under I (V) injection [129,132] and of isoconcentration diffusion experiments [133] reveal the charge states of the mobile B-related defect and of the native point defects involved in B diffusion. Altogether, B diffusion in Si under various experimental conditions is consistently described by the following reactions [64] with neutral (I 0 ), singly and doubly positively (I C , I 2C ) charged self-interstitials and neutral (V 0 ), singly positive (V C ), and singly and doubly negative (V , V 2 ) vacancies.…”

Section: Diffusion Profiles Of Dopant Atomsmentioning

confidence: 98%

“…This and the shape of the As diffusion profiles points to a foreign-atom controlled mode of dopant diffusion. Indeed available experimental results on As diffusion in Si, which comprise As diffusion experiments under native defect injection [68,132], under isoconcentration conditions [148], and on the simultaneous self-and dopant-atom diffusion [64], are accurately described by the defect reactions Various charge states for V (2 fV C ; V 0 ; V ; V 2 g and I (2 fI 2C ; I C ; I 0 ; I g) were assumed as well as neutral and singly negatively charged dopant-vacancy pairs AsV 0 and AsV . The parameters deduced from modeling As diffusion reveal a foreignatom controlled mode of diffusion, i.e., the equilibrium concentration of V and I is not disturbed by the diffusion of As.…”

Section: Diffusion Profiles Of Dopant Atomsmentioning

confidence: 99%

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Diffusion and Point Defects in Silicon Materials

Bracht

2015

Lecture Notes in Physics

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This chapter aims to provide a basic understanding on the complex diffusion behavior of self-, dopant-, and selected metal atoms in silicon (Si). The complexity of diffusion in Si becomes evident in the shape of self-and foreign-atom diffusion profiles that evolves under specific experimental conditions. Diffusion studies attempt to determine from the diffusion behavior not only the mechanisms of atomic transport but also the type of the point defects involved. This information is of pivotal interest to control the diffusion and activation of dopants during the fabrication of Si-based devices and, from a more fundamental scientific point of view, for comparison to the predictions of theoretical calculations on the properties of point defects in Si. In general, diffusion research relies both on experimental methods to accurately determine diffusion profiles established under well-defined conditions. The analysis of diffusion profiles that can be based on either analytical or numerical solutions of the considered diffusion-reaction equations provides first information about possible diffusion mechanisms. To identify the mechanisms of diffusion, studies under different experimental conditions have to be performed. This chapter on diffusion in Si starts with an introduction on the significance of diffusion research in semiconductors to determine the properties of atomic defects. Diffusion in solids is treated from a phenomenological and atomistic point of view. Experiments designed to investigate the diffusion of self-and foreign atoms are presented and typical self-and foreign-atom profiles obtained after diffusion annealing under specific conditions are illustrated. The mathematical treatment of diffusion-reaction mechanisms is introduced to understand the shape of diffusion profiles and the meaning of the diffusion coefficient deduced from experiments. Modeling of self-, dopant-, and metal-atom diffusion is described that aims at a consistent interpretation of atomic transport processes in Si based on unified properties of the native point defects involved. Finally, till unsolved questions on the properties of point defects in bulk Si and on the diffusion behavior in threedimensional confined Si structures are addressed.

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Section: Diffusion Profiles Of Dopant Atomsmentioning

confidence: 98%

Section: Diffusion Profiles Of Dopant Atomsmentioning

confidence: 99%

Diffusion and Point Defects in Silicon Materials

Bracht

2015

Lecture Notes in Physics

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“…Despite this emphasis, substantial disagreements remain about the relative concentrations and mobilities of the point defects involved in the diffusion of many substitutional elements in Si. Such disagreements arise frequently because the interpretation of diffusion experiments in terms of atomistic mechanisms is often indirect and model-based [2].…”

Section: Introductionmentioning

confidence: 99%

Pressure and Stress Effects on Diffusion in Si

Aziz¹

1997

DDF

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The thermodynamics of diffusion under hydrostatic pressure and nonhydrostatic stress is presented for single crystals free of extended defects. The thermodynamic relationships obtained permit the direct comparison of hydrostatic and biaxial stress experiments and of atomistic calculations under hydrostatic stress for any proposed mechanism. Atomistic calculations of the volume changes upon point defect formation and migration, and experiments on the effects of pressure and stress on the diffusivity, are reviewed. For Sb in Si, using as input the results of ab initio calculations of the effect of hydrostatic pressure on diffusion by the vacancy mechanism, the thermodynamic relationships successfully account for the measured effect of biaxial stress on diffusion with no free parameters. For other cases, missing parameters are enumerated and experimental and calculational procedures outlined.

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“…C~ -1 + kiC* [4] This equation indicates that the surface excess interstitial 10-16 concentration depends on the value of the equilibrium in-0.001 terstitial concentration, which in turn depends on the interstitial charge states.…”

Section: Glmentioning

confidence: 99%

Oxidation Enhanced Diffusion of Phosphorus in Silicon in Heavily Doped Background Concentrations

John

Law

1993

J. Electrochem. Soc.

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An experimental study investigates the oxidation-enhanced diffusion of phosphorus in silicon in both heavily doped boron and arsenic backgrounds at 900 and 1100~ This data can be modeled using the interstitial charge state levels to control the equilibrium concentration as a function of doping. The interstitials are assumed to be composed of only positive, negative, and neutral interstitial defects. The same values for the charge states are used to model previously published investigations of boron oxidation-enhanced diffusion under extrinsic isoeoncentration conditions. This indicates that these effects are not strongly dependent on the value of the fractional interstitialey, since two different dopants exhibit similar behavior.Understanding oxidation enhanced diffusion is important for modern process fabrication technology. The use of the lightly doped drain (LDD) MOS devices for channel lengths below 2 izm is critical for reliability concerns. One final step in a typical LDD process involves the anneal of the n § source/drain in dry oxygen to regrow the oxide on the silicon surface. Only through the complete understanding of the processes involved can optimization of the device structure be done. Controlling the junction depth can influence such factors as the diffusion spread under the masks and the depletion capacitance in the well.Shockley and Last 1 derived relationships for the thermal equilibrium concentration of charged defects in semiconductors. These relationships arewhere Eg is the bandgap as a function of temperature, C~ is the concentration of interstitials with the superscript +, o, -refer to the positive, neutral, and negative charge states, respectively, EF and Er are the negative and positive charge state levels, and E~ and E~ refer to the conduction and valence band energies. In thermal equilibrium the total concentration is given by the sum of all the concentrations in the various charge states, and is dependent on the electron concentration. During oxidation, interstitials are injected from and recombine at the surface. Hu 2 derived the surface boundary condition for interstitials during oxidation10_12 V is the surface injection, kl is the surface recombi-] where gl nation rate, D~ is the interstitial diffusivity, and C* is the

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Kinetics of thermal nitridation processes in the study of dopant diffusion mechanisms in silicon

Cited by 165 publications

References 7 publications

Diffusion and Point Defects in Silicon Materials

Diffusion and Point Defects in Silicon Materials

Pressure and Stress Effects on Diffusion in Si

Oxidation Enhanced Diffusion of Phosphorus in Silicon in Heavily Doped Background Concentrations

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