Growth mechanisms study of microcrystalline silicon deposited by SiH4/H2 plasma using tailored voltage waveforms

Bruneau, Bastien; Wang, J.; Dornstetter, Jean-Christophe; Johnson, Erik

doi:10.1063/1.4866693

Cited by 30 publications

(33 citation statements)

References 21 publications

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“…These results correlated with the contribution of ions to the deposit (methane ∼60%, acetylene ∼20%) and the ion energy flux to the film per deposited carbon atom. For silane plasmas, the role of ion energy in determining the crystallinity of the film has also been shown [27]. In the case of functional plasma polymers, the trends are less clearly defined.…”

Section: Film Physical and Mechanical Propertiesmentioning

confidence: 99%

“…From early in the development of silane based films, both neutrals and ions were considered important [24,25]. Researchers in this field have studied the plasma phase mass spectra of both neutrals and ions [26] and controlled the ion energy to elucidate the role of SiH x radicals, SiH + x ions and even H + ions in the deposition process [27]. A strong dependence on the plasma pressure is observed with Perrin [28] demonstrating that the contribution of ions to the deposit varies between nearly 100% at 0.1 Pa down to around 1% at 100 Pa.…”

Section: Silane Filmsmentioning

confidence: 99%

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The importance of ions in low pressure PECVD plasmas

2015

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Plasma enhanced chemical vapor deposition (PECVD) can be used to fabricate surfaces with a wide range of physical and chemical properties and are used in a variety of applications. Despite this, the mechanisms by which PECVD films grow are not well understood. Moreover, the species which contribute to film growth can be considered quite differently depending on the process. Particularly for functionalized plasma polymer films, the growth mechanisms are considered with respect to the chemistry of the depositing species, ignoring the physics of plasmas. Here we analyse the role ions play in the deposition of three common classes of depositing plasmas, and how these closely related fields treat ions very differently.

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Section: Film Physical and Mechanical Propertiesmentioning

confidence: 99%

Section: Silane Filmsmentioning

confidence: 99%

The importance of ions in low pressure PECVD plasmas

2015

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“…When they are applied to the growth of silicon thin films by plasma enhanced chemical vapor deposition (PECVD), one can gain more insight into the physical principles governing film growth and the optimization of process parameters. For instance, the control over the maximum ion bombardment energy (IBE) has been used to detail the growth mechanisms and material properties of hydrogenated microcrystalline silicon (μc-Si:H) [7][8][9], and for the case of crystalline silicon epitaxial growth, a critical IBE threshold only below which epitaxy can be sustained has also been quantitatively estimated using TVWs [10].…”

mentioning

confidence: 99%

Deposition of a‐Si:H thin films using tailored voltage waveform plasmas: impact on microstructure and stability

Wang

Longeaud

Ventosinos

et al. 2016

Phys. Status Solidi C

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Exciting processing plasmas using non‐sinusoidal, “Tailored” voltage waveforms (TVWs), have recently been shown to be effective to separately control the maximum ion bombardment energy (IBE) and the ion flux on each electrode in the capacitively coupled plasma (RF‐CCP) processes. In this work, we use it to deposit hydrogenated amorphous silicon (a‐Si:H) thin films from hydrogen‐diluted silane by low temperature plasma‐enhanced chemical vapor deposition. The impact of using TVWs on the material's structural and electronic properties is examined. Excessively low IBE can lead to a high Si‐H2bonded hydrogen content within the deposited films, which results in a deterioration of the material stability upon light‐soaking, detectable at a microstructure level. A low content of hydrogen bonded in a Si‐H2configuration and a low sub‐gap density of states was observed in the film deposited using a “sawtooth‐down” type of waveform. Such excitation also produced the a‐Si:H films with the best transport properties (majority and minority carrier μτ‐products and the ambipolar diffusion length) and stability under light‐soaking. (© 2016 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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“…The ion flux at the substrate is one of the principal parameters in determining the rate of a process and as such it is one of the key parameters that plasma control strategies aim to optimise. The ion bombardment energy required is largely process dependent with certain processes requiring low ion energies [1,2] and other processes requiring ion energies above certain thresholds in order to break bonds on the substrate.…”

Section: Introductionmentioning

confidence: 99%

Controlling plasma properties under differing degrees of electronegativity using odd harmonic dual frequency excitation

Gibson

Gans

2017

Plasma Sources Sci. Technol.

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The charged particle dynamics in low-pressure oxygen plasmas excited by odd harmonic dual frequency waveforms (low frequency of 13.56 MHz and high frequency of 40.68 MHz) are investigated using a one-dimensional numerical simulation in regimes of both low and high electronegativity. In the low electronegativity regime, the time and space averaged electron and negative ion densities are approximately equal and plasma sustainment is dominated by ionisation at the sheath expansion for all combinations of low and high frequency and the phase shift between them. In the high electronegativity regime, the negative ion density is a factor of 15-20 greater than the low electronegativity cases. In these cases, plasma sustainment is dominated by ionisation inside the bulk plasma and at the collapsing sheath edge when the contribution of the high frequency to the overall voltage waveform is low. As the high frequency component contribution to the waveform increases, sheath expansion ionisation begins to dominate. It is found that the control of the average voltage drop across the plasma sheath and the average ion flux to the powered electrode are similar in both regimes of electronegativity, despite the differing electron dynamics using the considered dual frequency approach. This offers potential for similar control of ion dynamics under a range of process conditions, independent of the electronegativity. This is in contrast to ion control offered by electrically asymmetric waveforms where the relationship between the ion flux and ion bombardment energy is dependent upon the electronegativity.

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Growth mechanisms study of microcrystalline silicon deposited by SiH4/H2 plasma using tailored voltage waveforms

Cited by 30 publications

References 21 publications

The importance of ions in low pressure PECVD plasmas

The importance of ions in low pressure PECVD plasmas

Deposition of a‐Si:H thin films using tailored voltage waveform plasmas: impact on microstructure and stability

Controlling plasma properties under differing degrees of electronegativity using odd harmonic dual frequency excitation

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