The mechanism of impurity diffusion in silicon

Dobson, P. S.

doi:10.1080/14786437208220343

Cited by 17 publications

(4 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Dobson (9,10) indicated that the interface oxidation reaction may include the filling of a silicon-lattice vacancy at the interface by an oxygen atom to annihilate a silicon vacancy and/or the occupying of a silicon site by an oxygen atom to create a silicon interstitial.…”

Section: (7)mentioning

confidence: 99%

Si / SiO2 Interface Oxidation Kinetics: A Physical Model for the Influence of High Substrate Doping Levels: I . Theory

Plummer

1979

J. Electrochem. Soc.

132

View full text Add to dashboard Cite

A physical model based on the statistics of silicon point defects is proposed to explain the commonly observed enhanced oxidation rates of heavily doped silicon. The physical effect of the high doping levels on the Si/SiO2 interface oxidation kinetics is postulated to be primarily electrical in nature. The high doping levels shift the position of the Fermi level toward the conduction band (n-type) or toward the valence band (p-type) even at oxidation temperatures, causing an increase in the equilibrium concentration of point defects (vacancies) in the silicon substrate. These point defects may provide reaction sites for the chemical reaction converting Si to SiQ and thereby increase the rate at which this reaction occurs. This paper describes the theoretical basis for this model and predicts quantitatively the expected oxidation rates for n +-and p+-doped silicon under a wide range of oxidation conditions. Integrated circuit structures and technologies continue to make extensive use of thermally grown silicon dioxide. It is well known that silicon heavily doped with donor or acceptor impurities, as commonly encountered in such device regions as bipolar emitter and MOS source/drain areas, may exhibit oxidation rates significantly enhanced relative to those observed for lightly doped silicon (1). An understanding of such dopant effects on oxidation kinetics, therefore, becomes of obvious importance to device process design and optimization.Some indication of the nature of these effects is contained in a considerable body of kinetic data recently reported for the thermal oxidation of heavily phosphorus-doped (111) oriented silicon in a dry oxygen ambient, in the temperature range 800~176(2). The observed enhancement of oxidation rate with increasing substrate doping levels, as shown for example in Fig. 1 from Ref. (2), is substantial, particularly at the lower oxidation temperatures studied. Oxide thickness vs. oxidation time is shown for six substrate types with the average electrically active phosphorus doping levels indicated. When reduced to the effective rate constants B and B/A of the Deal and Grove oxidation model (3), this enhancement is manifested primarily in a substantial increase in the linear rate constant B/A with increasing substrate doping. Apparently, however, there is only a relatively slight effect on the associated activation energy, as illustrated in Fig. 2 also taken from Ref. (2). Samples A through F in Fig. 2 have the same phosphorus doping levels as in Fig. 1.Analysis of these effects has led to the development of a physical model that may explain these observa-* Electrochemical Society Active Member.

show abstract

Section: (7)mentioning

confidence: 99%

Si / SiO2 Interface Oxidation Kinetics: A Physical Model for the Influence of High Substrate Doping Levels: I . Theory

Plummer

1979

J. Electrochem. Soc.

132

View full text Add to dashboard Cite

show abstract

“…It has been suggested (17)(18)(19)(20) that such an excess of interstitials and/or depletion of vacancies could be created by the oxidation process. Actually, interstitial flows may have some bearing on a possible orientation dependence of the vacancy contribution and the normalized (B/A)" at high doping levels.…”

Section: Discussionmentioning

confidence: 99%

“…J;oc. : SOLID-STATE SCIENCE AND TECHNOLOGY September I979 hanced dopant diffusion (17,18,20). Vacancy-related models abound for impurity diffusion (6,21,23,40,41).…”

Section: Kcvt = (K'civt)cic'vt Oc C'vtexp (~mentioning

confidence: 99%

Si / SiO2 Interface Oxidation Kinetics: A Physical Model for the Influence of High Substrate Doping Levels: II . Comparison with Experiment and Discussion

Plummer

1979

J. Electrochem. Soc.

View full text Add to dashboard Cite

A physical model based on the statistics of silicon point defects was described in the preceding companion paper to explain the faster oxidation rates of heavily doped silicon. The mechanism by which dopant levels affect the interface oxidation rate was postulated to be an increase in reaction sites or silicon vacancies caused by the shifting of the Fermi level. The predictions of this model for n + and p+ silicon oxidation kinetics are tested in this paper under a wide variety of oxidation conditions. The physical meaning of the model and its implications for other process phenomena are pursued.

show abstract

“…La mesure est de plus non destructive. Cette méthodedétection optique de l'évolution de l'interface couche épitaxiée-substratprésente les avantages suivants : 1) on détecte l'évolution des impuretés choisies lorsque leur concentration est forte (> 1018 at/cm3) ; la mesure n'est donc pas perturbée par des défauts stables associés aux impu-retés résiduelles ; 2) la diffusion n'est pas perturbée par la surface qui peut jouer le rôle de pièges ou de sources de lacunes ou d'interstitiels ; Ghoshtagore [26] a en effet montré l'influence de la surface sur la diffusion (ainsi que Dobson [27]) : le « vrai » coefficient de diffusion qui régit l'évolution d'une interface couche épitaxiée-substrat est très inférieur aux divers coefficients qui ont pu être mesurés en faisant diffuser une impureté à partir de la surface. D'autre part, il est aisé de réaliser des couches de silicium épitaxiées contenant une forte concentration d'étain ou de germanium ; nous espérons pouvoir ainsi mettre en oeuvre la méthode du piégeage sélectif [28], [29] pour identifier le défaut responsable de la diffusion accélérée.…”

unclassified

Diffusion Accélérée. Nouvelle Méthode d'INVESTIGATION Et Application Aux Diodes Schottky Hyperfréquence

Damene¹,

Assemat²,

Pruniaux³

et al. 1973

J. Phys. Colloques

View full text Add to dashboard Cite

Nous avons étudié l'influence d'implantations d'ions (20 keV-500 keV) à chaud (20 OC-800 OC) sur diverses répartitions d'impuretés (B, P, As, Ga) dans du silicium et du germanium. Les techniques classiques d'analyse se sont révélées insuffisantes. Nous avons donc développé l'interférométrie infrarouge. La méthodedétection optique de la déformation du profil à l'interface couche épitaxiée-substratest non destructive et apparaît comme la meilleure pour l'étude des phénomènes de diffusion contrôlée par irradiation. De plus la diffusion à l'interface couche épitaxiéesubstrat n'est pas perturbée par la surface du semi-conducteur. Parmi les applications possibles de la diffusion contrôlée par implantation, nous étudions la diminution de la résistance série dans les diodes Schottky hyperfréquence. Nous pensons que la réduction de la dispersion des caractéristiques de ces composants grâce à l'homogénéisation de l'interface couche épitaxiéesubstrat est une bonne application de la diffusion accélérée par implantation.

show abstract

The mechanism of impurity diffusion in silicon

Cited by 17 publications

References 7 publications

Si / SiO2 Interface Oxidation Kinetics: A Physical Model for the Influence of High Substrate Doping Levels: I . Theory

Si / SiO2 Interface Oxidation Kinetics: A Physical Model for the Influence of High Substrate Doping Levels: I . Theory

Si / SiO2 Interface Oxidation Kinetics: A Physical Model for the Influence of High Substrate Doping Levels: II . Comparison with Experiment and Discussion

Diffusion Accélérée. Nouvelle Méthode d'INVESTIGATION Et Application Aux Diodes Schottky Hyperfréquence

Contact Info

Product

Resources

About