Oxidation, defects and vacancy diffusion in silicon

Sanders, I. R.; Dobson, P. S.

doi:10.1080/14786436908228058

Cited by 138 publications

(19 citation statements)

References 11 publications

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“…They can be shrunk by high temperature heat-treatment in an unoxidizing atmosphere. Sanders et aL (16) determined the activation energy for fault shrinkage to be 2.1 eV. This energy is smaller than the result of the present experiment, 5.2 eV.…”

Section: Discussioncontrasting

confidence: 78%

Annihilation of Stacking Faults in Silicon by Impurity Diffusion

Hashimoto

Shibayama

Masaki

et al. 1976

J. Electrochem. Soc.

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The stacking faults grown into silicon during thermal oxidation were shrunk by high temperature heat-treatment in a nitrogen atmosphere. The activation energy for fault shrinkage was 5.2 eV, and nearly equal to that of silicon self-diffusion, 5.13 eV. The shrinkage phenomenon is due to the removal of silicon atoms, which form the stacking faults of extrinsic type, by diffusion via vacancies. Therefore the shrinkage rate depends on the vacancy concentration" in silicon. The high concentration diffusion of boron, phosphorus, and arsenic in silicon generates the excess vacancies induced by donor doping, or by the stress due to solute lattice contraction of the impurity. The shrinkage of stacking faults by these excess vacancies was investigated. The faults shrank rapidly and disappeared for a short time in comparison with simple heat-treatment. The annihilation of stacking faults in silicon was also influenced by the coulomb interaction or the complex formation between the negatively charged vacancy and impurity.Thermal oxidation is one of the important processes in the manufacture of silicon planar transistors and other devices. Crystallographic defects such as stacking faults are often introduced in silicon in this oxidation process (1-5). When stacking faults lie across a p-n junction, excess reverse leakage currents in the junction are increased (6). Therefore, it is necessary to suppress stacking fault generation. If a crystal free from mechanical damage and grown-in defects, which act as the nucleation, is used, stacking faults are not generated. However, it is difficult to obtain such a crystal. Accordingly, the suppression of stacking fault generation and shrinkage of the faults by HC1 oxidation (7), or the preoxidation gettering of silicon wafers by misfit dislocations due to phosphorus diffusion (8), etc. have been carried out. Stacking faults also can be shrunk by high temperature heat-treatment (9).In this study, the shrinkage of stacking faults was investigated first. It was found that the shrinkage related intimately to the vacancy concentration in silicon. The vacancy concentration depends not only on treatment temperature, but also on impurity doping. And so the relation between the annihilation of stacking faults and the excess vacancies which were ~nduced during impurity diffusion into silicon was studied, and the mechanism of the annihilation is discussed. ExperimentalThe specimen wafers used in these experiments were 1-5 ~-cm (100) oriented dislocation-free silicon crystals grown by the Czochralski method. They were doped with phosphorus for n-type and boron for ptype. The surface was mechanically polished and the thickness was about 250 ~m. After appropriate treatments, they were etchd in a HF:HNO3 = 1:5 solution for 2 min to remove the surface mechanical damage. The oxidation of silicon was carried out at 1200~ in dry oxygen for 210 min. This thermal oxidation grew a stacking fault in the silicon crystal about 40 ~m long, provided that the fault size was defined as the fault length on the silic...

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Section: Discussioncontrasting

confidence: 78%

Annihilation of Stacking Faults in Silicon by Impurity Diffusion

Hashimoto

Shibayama

Masaki

et al. 1976

J. Electrochem. Soc.

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“…In the dual mechanism, the dopant diffusivity can be written in terms of interstitial and vacancy components DA ~A Ci Cv D*.-~ ~ + (1 -f~) C~ [11] where CI and Cv are the interstitial and vacancy concentrations, respectively, D, is the diffusivity of dopant A under a given condition, the * represents the equilibrium value in intrinsic material, and f~ is the fractional interstitialcy component of diffusion for dopant A. Since phosphorus diffuses predominantly via interstitials (f~ ~ 1), 4' 13 the phosphorus diffusivity enhancement is approximately equivalent to the interstitial supersaturation, and Dp_ CI [12] /9* -Q* Substituting Eq.…”

Section: Fig 3 the Arrhenius Plat Of Hdp Vs Oxynitridation Temperamentioning

confidence: 99%

Oxynitridation‐Enhanced Diffusion of Phosphorus in <100> Silicon

Chen¹,

Lee²

1995

J. Electrochem. Soc.

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2051various additional curing temperatures. This process was found to reproducib]y remove polyimide effectively without leaving any residual polyimide film on the interface. No electrical degradation was found in the die as a result of this decapsulation process. It offers a useful deprocessing tool for failure analysts. Further work is needed to understand the residual film observed after RIE. ABSTRACTDiffusion of phosphorus in silicon in an ambient of pure N2, pure NHs, and mixtures of NH5 and N2 has been investigated to study the effect of the oxynitridation reaction on the diffusivity. With a thin SiO2 layer on the silicon wafer and a low phosphorus concentration, the diffusion coefficient of phosphorus can be expressed as a function of the partial pressure of NH~ and temperature as D = 0.145 exp (-3.26 eV/kT) + 1.718 • 10 ~ exp (-1.72 eV/kT)pNH3 cm 2 s -1 At the same time, the ratio of the interstitial concentration under oxynitridation conditions to the concentration under inert conditions can be expressed as CI 1 + 1.183 • 10 -5 exp (1.54 eV/kT)pNH3Ci, -By using P diffusion as an interstitial monitor, the data (Ref. 1) of oxynitridation-enhanced B diffusion are analyzed and the fraction of boron diffusion which occurs through the interstitial mechanism is calculated to be 0.88.

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“…In the channel where the oxide is always relatively thin, the unfaulting would evidently occur with comparative ease, and the resulting perfect dislocations would be able to climb out of the silioon. 9 The driving force for the climb process would be the image force induced by the surface. At the edges of the polysilioon, the strain field …”

Section: Discussionmentioning

confidence: 99%