A new portrayal of electron and hole traps in amorphous silicon nitride

Kamigaki, Yoshiaki; Minami, Shin‐ichi; Kato, Hisayuki

doi:10.1063/1.346524

Cited by 56 publications

(16 citation statements)

References 24 publications

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“…1 These traps have been attributed to different types of silicon dangling bonds, termed K-center defects, based on electron spin resonance (ESR) measurements, [1][2][3][4] and electronic structure calculations of some native defects. [5][6][7][8] However, a comprehensive characterization of the atomic and electronic structure of e − and h + traps in silicon nitride is still missing.…”

Section: Introductionmentioning

confidence: 99%

Native defects in hexagonalβ-Si3N4
Grillo
¹
,
Elliott
²
,
Freysoldt
³

2011
Phys. Rev. B
36
3
12
0
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A comprehensive study of single native point defects in hexagonal silicon nitride (β-Si 3 N 4 ) has been carried out based on density functional calculations of formation energies. Both nitrogen-and silicon-rich native defect centers form donor and acceptor states in the band gap of β-Si 3 N 4 , confirming their amphoteric behavior. Silicon dangling bonds resulting from structural nitrogen vacancies (V N ) are the most abundant native defects, in particular, in their acceptor state (V − N and V 3− N ). Hydrogenation promotes the appearance of Si dangling bond defects in the neutral state consistent with the observation of paramagnetic centers in the gap of amorphous silicon nitrides by electron spin resonance. This explains the utility of silicon nitride as charge trapping layer in nonvolatile memories.

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Section: Introductionmentioning

confidence: 99%

Native defects in hexagonalβ-Si3N4
Grillo
¹
,
Elliott
²
,
Freysoldt
³

2011
Phys. Rev. B
36
3
12
0
View full text Add to dashboard Cite

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“…Hence the silicon dangling bonds can exchange electrons and the coulomb interaction at this distance is strong. However, experiments [4,19,20] showed that the electron trap density (N −1/3 and is about 60Å which much larger than that used in the ab initio DFT calculation conducted by Pacchioni and Erbetta [18]. At the distance estimated from the experimental trap density, the Coulomb interaction is too week to make the electron exchange between two N 3 Si· defects happening.…”

Section: (Received 30 January 2003)mentioning

confidence: 88%

“…In addition, if the distance between two defects is about 3.1Å, other mechanisms for the carrier localization are also possible. It was suggested that the electron and hole capturing could also occur at a neutral diamagnetic ≡ Si−Si ≡ defect [2,4,10,20,21]. The validity of these two models for Si 3 N 4 is still under discussion.…”

Section: (Received 30 January 2003)mentioning

confidence: 99%

Capturing properties of a threefold coordinated silicon atom in silicon nitride: Positive correlation energy model

et al. 2003

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Electronic structure and capturing properties of three-fold coordinated silicon atom (≡ Si·) and the Si-Si bond in silicon nitride (Si 3 N 4 ) were studied using the ab initio density functional theory. The results show that the previously proposed negative correlation energy (NCE) model is not applicable to Si 3 N 4 . The NCE model was proposed for interpreting the absence of the ESR signal for three-fold coordinated silicon defects and suggested that an electron can transfer between two silicon defects. We proposed that the absence of this ESR signal is due to the creation of neutral diamagnetic Si-Si defects in Si 3 N 4 . This model offers the most fundamental theory for explaining the hole localization (memory) effect in silicon nitride.This work is partially supported by research project N 7001134 of City U.Carrier capturing in localized states or localization of electrons or holes is a fundamental process that governs the electronic properties of many amorphous solids, such as amorphous silicon, amorphous chalcogenides (a-Se, a-As 2 S 3 ) and silicon nitride (Si 4 N 4 ) films [1-4]. Particularly, amorphous Si 3 N 4 is the most common material for observing this phenomenon as it has a gigantic cross-section (5 × 10 −13 cm) for carrier capturing. An electron or a hole, being injected into the Si 3 N 4 film, can be captured by a deep trap with a lifetime in the localized state of more than 10 years at room temperature [4]. This localization property is treated as memory effect from the application point of view. Its practical application is the use of amorphous Si 3 N 4 as a gate dielectric in the SONOS (silicon-oxide-nitrideoxide-semiconductor) field effect transistors. Although this memory effect has been discovered for more than thirty years and is widely used in modern silicon devices [2,[4][5][6][7][8], the exact nature and the kind of defects responsible for the carrier localization in the nitride film is still controversial. However, we already had a consensus that the localization of electrons and holes in the Si 3 N 4 film is related to the intrinsic defects created by the excess silicon atoms [2,4,8,9].The intrinsic defects in amorphous solids are believed to be due to the dangling bonds. However, most of the defects could not be detected with the electron spin resonance (ESR) measurement in a number of amorphous semiconductors and wide-gap polar dielectrics such as amorphous SiO 2 and Si 3 N 4 films [1-4,10]. The signal for N 3 Si· defect in silicon nitride, a three-fold coordinated silicon atom with unpaired electron, could be detected with ESR only after ultraviolet irradiation [11]. For freshly synthesized nitride film, no related ESR signal can be detected. This observation was explained with the negative correlation energy (NCE) model [12,13]. This model suggested that two diamagnetic defects: a positively charged N 3 Si + and a negatively charged N 3 Si − :, can be formed from a N 3 Si· (paramagnetic neutral defects in Si 3 N 4 ) pair via the following reaction,In the NCE model, the repulsive...

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“…Our works extends the model based on electron and hole trapping at the O 3 Si=Si O 3 defect in silica (see Fig. 1) proposed earlier (1,2,8) and predict the geometry, electronic structure and spectroscopic properties of doubly ionized and negatively charged oxygen vacancies in a-SiO 2 . We argue that the oxygen vacancies can be responsible for both the electron and hole trapping in silica.…”

Section: Ecs Transactions 19 (2) 3-17 (2009)mentioning

confidence: 93%

Positive and Negative Oxygen Vacancies in Amorphous Silica

et al. 2009

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We modeled all stable positive and negative charge states of oxygen vacancies originating from the neutral O 3 Si=Si O 3 defect in amorphous SiO 2 (a-SiO 2 ) using an embedded cluster method on a distribution of structural sites. For the first time, we predict the geometry, electronic structure and spectroscopic properties of doubly ionized and negatively charged oxygen vacancies in a-SiO 2 and demonstrate that negatively charged vacancies serve as deep electron traps. The results demonstrate that oxygen vacancies can be responsible for both the electron and hole trapping in silica. We compare our findings with the previous calculations and with the recent experimental data.

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A new portrayal of electron and hole traps in amorphous silicon nitride

Cited by 56 publications

References 24 publications

Native defects in hexagonalβ-Si3N4
Grillo
¹
,
Elliott
²
,
Freysoldt
³

2011
Phys. Rev. B
36
3
12
0
View full text Add to dashboard Cite

Native defects in hexagonalβ-Si3N4
Grillo
¹
,
Elliott
²
,
Freysoldt
³

2011
Phys. Rev. B
36
3
12
0
View full text Add to dashboard Cite

Capturing properties of a threefold coordinated silicon atom in silicon nitride: Positive correlation energy model

Positive and Negative Oxygen Vacancies in Amorphous Silica

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A new portrayal of electron and hole traps in amorphous silicon nitride

Cited by 56 publications

References 24 publications

Native defects in hexagonalβ-Si3N4Grillo1, Elliott2, Freysoldt3 2011Phys. Rev. B363120View full textAdd to dashboardCite

Native defects in hexagonalβ-Si3N4Grillo1, Elliott2, Freysoldt3 2011Phys. Rev. B363120View full textAdd to dashboardCite

Capturing properties of a threefold coordinated silicon atom in silicon nitride: Positive correlation energy model

Positive and Negative Oxygen Vacancies in Amorphous Silica

Contact Info

Product

Resources

About

Native defects in hexagonalβ-Si3N4
Grillo
¹
,
Elliott
²
,
Freysoldt
³

2011
Phys. Rev. B
36
3
12
0
View full text Add to dashboard Cite

Native defects in hexagonalβ-Si3N4
Grillo
¹
,
Elliott
²
,
Freysoldt
³

2011
Phys. Rev. B
36
3
12
0
View full text Add to dashboard Cite