Chemically Bound Hydrogen in CVD Si3 N 4: Dependence on  NH 3 / SiH4 Ratio and on Annealing

Stein, H. J.; Wegener, H. A. R.

doi:10.1149/1.2133451

Cited by 92 publications

(36 citation statements)

References 7 publications

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“…The effective absorption cross-section S eff for valence vibration of Si-N bonds is 1.6 · 10 −19 cm 2 [10], and S eff for valence vibration of Si-H bonds is 0.57 · 10 −19 cm 2 [11]. According to different data, S eff for valence vibration of N-H bonds is 0.48 · 10 −19 cm 2 [11] or 0.8 · 10 −19 cm 2 [12]. Concentration of chemical species can be calculated as N(cm −3 ) = A/(d(cm)· S eff (cm 2 )), where A is the height of absorbance peak (dimensionless parameter) and d is thickness.…”

Section: Resultsmentioning

confidence: 99%

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Vibrational Spectroscopy of Chemical Species in Silicon and Silicon-Rich Nitride Thin Films

Bugaev

Zelenina

Володин

2012

International Journal of Spectroscopy

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Vibrational properties of hydrogenated silicon-rich nitride (SiN x :H) of various stoichiometry (0.6 ≤ x ≤ 1.3) and hydrogenated amorphous silicon (a-Si:H) films were studied using Raman spectroscopy and Fourier transform infrared spectroscopy. Furnace annealing during 5 hours in Ar ambient at 1130 • C and pulse laser annealing were applied to modify the structure of films. Surprisingly, after annealing with such high-thermal budget, according to the FTIR data, the nearly stoichiometric silicon nitride film contains hydrogen in the form of Si-H bonds. From analysis of the FTIR data of the Si-N bond vibrations, one can conclude that silicon nitride is partly crystallized. According to the Raman data a-Si:H films with hydrogen concentration 15% and lower contain mainly Si-H chemical species, and films with hydrogen concentration 30-35% contain mainly Si-H 2 chemical species. Nanosecond pulse laser treatments lead to crystallization of the films and its dehydrogenization.

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Section: Resultsmentioning

confidence: 99%

“…The concentration of N-H species is calculated using S eff according to Lanford [11] and Stein [12]. It should be noted that Stein and Wegener [12] have used multiple internal transmissions but Lanford and Rand [11] used normal transmission geometry. We also have used normal transmission geometry.…”

Section: Resultsmentioning

confidence: 99%

Vibrational Spectroscopy of Chemical Species in Silicon and Silicon-Rich Nitride Thin Films

Bugaev

Zelenina

Володин

2012

International Journal of Spectroscopy

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“…However, unlike atomic H diffusion, this process requires a preceding chemical reaction during which the small molecules dissociate from the network. 5 Since the dissociation energies and the activation energy of the atomic diffusion process have the same order of magnitude ͑eV range͒ the overall H-bond density in a given film is reduced for both mechanisms in a similar way making it difficult to distinguish the two effects and their consequences on the H reduction during the anneal. Since the possibility of H permeation into the c-Si substrate depends on the H density at the interface, the type of H transport mechanism in the silicon nitride is of crucial importance.…”

Section: Introductionmentioning

confidence: 99%

H loss mechanism during anneal of silicon nitride: Chemical dissociation

Boehme

Lucovsky

2000

Journal of Applied Physics

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Influence of the high-temperature "firing" step on high-rate plasma deposited silicon nitride films used as bulk passivating antireflection coatings on silicon solar cells Remote plasma enhanced chemical vapor deposited silicon nitride (Si x N y H z ), produced at high ammonia to silane flow rates ͑ammonia rich͒ shows a reduction of hydrogen during rapid thermal anneal at temperatures that exceed the deposition temperature. This H release could be either due to a ''slow'' atomic diffusion of the covalent bonded atoms between bonding sites, or to a ''fast'' molecular diffusion of hydrogen containing molecules ͑e.g., H 2 , NH 3 , SiH 4 ), which dissociate from the network before they diffuse. In order to determine the dominant mechanism, layers of deuterated and hydrogenated silicon nitride on top of a crystalline Si substrate were annealed and the development of the NH-and ND-area densities were measured with Fourier transform infrared spectroscopy. Comparison of theoretical models with the measurements showed that chemical dissociation and subsequent rapid diffusion are the dominant processes. These results were confirmed by secondary ion mass spectroscopy. The experiments indicate that the H reduction in silicon nitride antireflection coatings of solar cells is mostly due to H migration out of the system and not into the Si area and make the hypothesis that postdeposition annealing of solar cell antireflection coatings can cause H-related bulk passivation of the underlying c-Si therefore questionable.

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“…40,46 In the absence of H 2 , the observed Si−H bonds arose from the silane. 26 23 and thus the effectiveness as a diffusion barrier.…”

Section: Resultsmentioning

confidence: 99%

Influence of Chemical Composition and Structure in Silicon Dielectric Materials on Passivation of Thin Crystalline Silicon on Glass

Calnan

Gabriel

Rothert

et al. 2015

ACS Appl. Mater. Interfaces

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In this study, various silicon dielectric films, namely, a-SiOx:H, a-SiNx:H, and a-SiOxNy:H, grown by plasma enhanced chemical vapor deposition (PECVD) were evaluated for use as interlayers (ILs) between crystalline silicon and glass. Chemical bonding analysis using Fourier transform infrared spectroscopy showed that high values of oxidant gases (CO2 and/or N2), added to SiH4 during PECVD, reduced the Si-H and N-H bond density in the silicon dielectrics. Various three layer stacks combining the silicon dielectric materials were designed to minimize optical losses between silicon and glass in rear side contacted heterojunction pn test cells. The PECVD grown silicon dielectrics retained their functionality despite being subjected to harsh subsequent processing such as crystallization of the silicon at 1414 °C or above. High values of short circuit current density (Jsc; without additional hydrogen passivation) required a high density of Si-H bonds and for the nitrogen containing films, additionally, a high N-H bond density. Concurrently high values of both Jsc and open circuit voltage Voc were only observed when [Si-H] was equal to or exceeded [N-H]. Generally, Voc correlated with a high density of [Si-H] bonds in the silicon dielectric; otherwise, additional hydrogen passivation using an active plasma process was required. The highest Voc ∼ 560 mV, for a silicon acceptor concentration of about 10(16) cm(-3), was observed for stacks where an a-SiOxNy:H film was adjacent to the silicon. Regardless of the cell absorber thickness, field effect passivation of the buried silicon surface by the silicon dielectric was mandatory for efficient collection of carriers generated from short wavelength light (in the vicinity of the glass-Si interface). However, additional hydrogen passivation was obligatory for an increased diffusion length of the photogenerated carriers and thus Jsc in solar cells with thicker absorbers.

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Chemically Bound Hydrogen in CVD Si3 N 4: Dependence on NH 3 / SiH4 Ratio and on Annealing

Cited by 92 publications

References 7 publications

Vibrational Spectroscopy of Chemical Species in Silicon and Silicon-Rich Nitride Thin Films

Vibrational Spectroscopy of Chemical Species in Silicon and Silicon-Rich Nitride Thin Films

H loss mechanism during anneal of silicon nitride: Chemical dissociation

Influence of Chemical Composition and Structure in Silicon Dielectric Materials on Passivation of Thin Crystalline Silicon on Glass

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