Atmospheric pressure chemical vapor deposition mechanism of Al2O3 film from AlCl3 and O2

Nasution, Indera Sakti; Velasco, Angelito; Kim, Hee‐Joon

doi:10.1016/j.jcrysgro.2008.11.061

Cited by 15 publications

(6 citation statements)

References 26 publications

(36 reference statements)

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“…Additionally, the rates presented in table 4 do not exhibit clear trends in growth behavior. As reported previously, the atmospheric ('open-air') deposition of Al 2 O 3 using the highly pyrophoric precursor TMA, can be challenging to reproduce [56]. The ambient oxygen and water in the air (humid conditions) can act as an additional oxygen source that can increase growth rates [57].…”

Section: Film Nucleation and Growthmentioning

confidence: 99%

In-situ observation of nucleation and property evolution in films grown with an atmospheric pressure spatial atomic layer deposition system

et al. 2020

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Atmospheric pressure-spatial atomic layer deposition (AP-SALD) is a promising open-air deposition technique for high-throughput manufacturing of nanoscale films, yet the nucleation and property evolution in these films has not been studied in detail. In this work, in situ reflectance spectroscopy was implemented in an AP-SALD system to measure the properties of Zinc oxide (ZnO) and Aluminum oxide (Al 2 O 3 ) films during their deposition. For the first time, this revealed a substrate nucleation period for this technique, where the length of the nucleation time was sensitive to the deposition parameters. The in situ characterization of thickness showed that varying the deposition parameters can achieve a wide range of growth rates (0.1-3 nm/cycle), and the evolution of optical properties throughout film growth was observed. For ZnO, the initial bandgap increased when deposited at lower temperatures and subsequently decreased as the film thickness increased. Similarly, for Al 2 O 3 the refractive index was lower for films deposited at a lower temperature and subsequently increased as the film thickness increased. Notably, where other implementations of reflectance spectroscopy require previous knowledge of the film's optical properties to fit the spectra to optical dispersion models, the approach developed here utilizes a large range of initial guesses that are inputted into a Levenberg-Marquardt fitting algorithm in parallel to accurately determine both the film thickness and complex refractive index.

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Section: Film Nucleation and Growthmentioning

confidence: 99%

In-situ observation of nucleation and property evolution in films grown with an atmospheric pressure spatial atomic layer deposition system

et al. 2020

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“…Another commonly used and inexpensive precursor for CVD of Al 2 O 3 is the metal-halide aluminium chloride (AlCl 3 ). However this too is solid at room temperature, requires high deposition temperatures (typically between 700 and 1000 • C [120]), and produces corrosive HCl as a by-product of the deposition reaction.…”

Section: Chemical Precursorsmentioning

confidence: 99%

New Perspectives on Surface Passivation: Understanding the Si-Al2O3 Interface

Black

2016

Springer Theses

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High-efficiency crystalline silicon solar cells must suppress recombination at their p-type surfaces. Thin-film, amorphous aluminium oxide (Al 2 O 3) has been shown to provide very effective passivation of such surfaces, assisted by its negative fixed charge. However, many details of Al 2 O 3 passivation remain poorly understood. Furthermore, conventional means of depositing passivating Al 2 O 3 are too slow or too expensive to be suitable for high-volume commercial production. This thesis addresses these issues in three ways: 1) by contributing to a deeper understanding of semiconductor-dielectric interfaces and semiconductor surface recombination mechanisms in general, 2) by investigating the properties of Al 2 O 3 as a passivating dielectric for silicon surfaces, and 3) by demonstrating the viability of APCVD as a high-throughput, industrially compatible deposition method for Al 2 O 3 , enabling its application to commercial solar cells. Using Al 2 O 3 as a test case, it is shown how a novel analysis of the extended conductance method can be used to i) distinguish the separate contributions to the interface state distribution at a semiconductor-dielectric interface, and ii) determine their capture cross-sections for both minority and majority carriers. Furthermore, the direct link between these measured interface state properties and the recombination rate at the semiconductor surface is experimentally demonstrated by showing that the former can be used to accurately predict the latter. Investigations of the surface passivation properties of Al 2 O 3 reveal a remarkably consistent picture. It is shown that the properties of the Si-Al 2 O 3 interface states are essentially independent of the Al 2 O 3 deposition conditions and technique. The interface properties are found to be independent of the surface dopant concentration at boron-and phosphorus-doped surfaces, while recombination is shown to be only weakly dependent on surface orientation and morphology as a result of the remarkable orientation-independence of the Si-Al 2 O 3 interface state properties. Meanwhile, the chemical origin of the charge at the Si-Al 2 O 3 interface is elucidated by correlating FTIR and electrical measurements. xi xii APCVD is clearly shown-for the first time-to be capable of depositing Al 2 O 3 films with exceptional surface passivation properties, comparable to the best results achieved using other deposition techniques. In the best case, interface state densities as low as 5 × 10 10 eV −1 cm −2 at midgap, and negative fixed charge concentrations of 3.3 × 10 12 cm −2 are measured, resulting in a saturation current density of 7 fA cm −2 on undiffused p-type surfaces. The APCVD films are shown to be thermally stable under standard solar cell processing conditions and are demonstrated in large-area solar cells with peak efficiencies of 21.3 %. These results demonstrate the viability of APCVD Al 2 O 3 as a surface passivation layer for industrial silicon solar cells.

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“…4),5), 7) However, the obtained Al 2 O 3 thin films deposited at lower temperatures tend to include chlorine residue. 8) Recently, much attention has been paid to TMA [Al(CH 3 ) 3 ] as aluminum source. By atomic layer deposition, 11)13) dense and amorphous Al 2 O 3 thin-films can be obtained.…”

Section: Introductionmentioning

confidence: 99%

Effect of deposition conditions and buffer layers on amorphous or polytype phase formation in Al<sub>2</sub>O<sub>3</sub> thin films by chemical vapor deposition using tri-methyl aluminum

Cheng

Tanaka

Nishiyama

et al. 2019

J. Ceram. Soc. Japan

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Al 2 O 3 thin films were deposited on (001)Si substrate through Cr 2 O 3 /yttria-stabilized-zirconia (YSZ) buffer layer by cold-wall type chemical vapor deposition method with tri-methyl aluminum as a raw material. By changing the deposition temperature, different polytypes of Al 2 O 3 thin films were formed. At lower temperatures (1123 1173 K), ©-Al 2 O 3 and amorphous Al 2 O 3 were found in mixture. With increasing the deposition temperature, the series of Al 2 O 3 polytypes (£, ¬ and ¡) appeared in the order of decreasing the unit cell volume per Al atom. At 1323 K, single-phase ¡-Al 2 O 3 thin film was obtained in success. On (00l)Cr 2 O 3 /YSZ/Si substrate, epitaxial (00l)¡-Al 2 O 3 thin-film was grown, however, on (00l)YSZ/Si substrate, epitaxial (00l)¬-Al 2 O 3 thin film was formed. It shows that buffer layer also has much influence on polytype of Al 2 O 3 thin film. On the other hand, there exist the polycrystalline ¡-Al 2 O 3 and Cr 2 O 3 have the same Miller index (h k l), therefore, polycrystalline ¡-Al 2 O 3 thin film was deposited on the polycrystalline Cr 2 O 3 buffer layer in which each Al 2 O 3 and Cr 2 O 3 grain has an epitaxial relation. This epitaxial growth can be explained by both the similarity in crystal structure between Al 2 O 3 film and Cr 2 O 3 buffer layer, and also their moderate lattice mismatch.

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Atmospheric pressure chemical vapor deposition mechanism of Al2O3 film from AlCl3 and O2

Cited by 15 publications

References 26 publications

In-situ observation of nucleation and property evolution in films grown with an atmospheric pressure spatial atomic layer deposition system

In-situ observation of nucleation and property evolution in films grown with an atmospheric pressure spatial atomic layer deposition system

New Perspectives on Surface Passivation: Understanding the Si-Al2O3 Interface

Effect of deposition conditions and buffer layers on amorphous or polytype phase formation in Al<sub>2</sub>O<sub>3</sub> thin films by chemical vapor deposition using tri-methyl aluminum

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