Effects of substrate bias on structure and properties of a-Si:H films deposited by ECR microwave plasmas

Herak, T. V.; Chau, T. T.; Mejia, S. R.; Shufflebotham, P. K.; Schellenberg, John; Card, H.C.; Kao, K. C.; McLeod, R.D.

doi:10.1016/0022-3093(87)90066-4

Cited by 11 publications

(4 citation statements)

References 5 publications

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“…It is worth noting that the literature reports of production of the best quality semiconductor nanocrystals from low-pressure plasmas use pressures that, according to our present results, coincide with an enhanced ion flux and a reduced ion energy [14]. As our results have shown, for small pressures (P < 100 Pa) there is a considerable fraction of ions with energies above the binding energy for Si-Si and Si-H surface species (≈3 eV) [38]; however, at larger pressures the particle potential becomes less negative and a large fraction of ions impinges at or below the binding energy. It may thus be expected that the IED of ions hitting the nanoparticles during growth plays an essential role, if ion flux is at least roughly on the order of the growth species flux of elementary silane radicals (e.g.…”

Section: Ion Energy [Ev] Iedf [Evsupporting

confidence: 82%

The energy distribution function of ions impinging on nanoparticles in a collisional low-pressure plasma

Galli¹,

Mamunuru²,

Kortshagen³

2012

Plasma Sources Sci. Technol.

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A self-consistent particle-in-cell/Monte Carlo collision (PIC/MCC) simulation is used to calculate the ion energy distribution (IED) function of ions impinging on the surface of nanoparticles in low-pressure argon plasmas. The computation includes the effects of resonant charge-exchange and elastic collisions between ions and neutrals through a Monte Carlo null-collision method and considers both Maxwellian and non-Maxwellian electron energy distributions. Results show a strong dependence of the IED on pressure. Intermediate pressures yield a remarkable reduction in the average ion energy and an enhancement in the ion flux to the surface of the nanoparticles.

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Section: Ion Energy [Ev] Iedf [Evsupporting

confidence: 82%

The energy distribution function of ions impinging on nanoparticles in a collisional low-pressure plasma

Galli¹,

Mamunuru²,

Kortshagen³

2012

Plasma Sources Sci. Technol.

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“…In recent studies it was shown that ion bombardment offers additional control over film growth, with promising results demonstrating dense films at deposition conditions usually resulting in void-rich low-density material. [5][6][7][8][9][10][11][12][13] It is therefore of great technological importance to understand the effect of ion bombardment on a-Si:H film growth, not only for the ETP-CVD technique but for any kind of plasma-involving CVD in general.…”

Section: Introductionmentioning

confidence: 99%

Hydrogenated amorphous silicon deposited under accurately controlled ion bombardment using pulse-shaped substrate biasing

Wank

Swaaij

Kudlacek

et al. 2010

Journal of Applied Physics

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We have applied pulse-shaped biasing to the expanding thermal plasma deposition of hydrogenated amorphous silicon at substrate temperatures ∼200 °C and growth rates around 1 nm/s. Substrate voltage measurements and measurements with a retarding field energy analyzer demonstrate the achieved control over the ion energy distribution for deposition on conductive substrates and for deposition of conductive materials on nonconductive substrates. Presence of negative ions/particles in the Ar–H2–SiH4 plasma is deduced from a voltage offset during biasing. Densification of the material at low Urbach energies is observed at a deposited energy <4.8 eV/Si atom and attributed to an increase in surface mobility of mobile species as well as well as surface atom displacement. The subsequent increase in Urbach energy >4.8 eV/Si atom is attributed to bulk atom displacement in subsurface layers. We make the unique experimental abservation of a decreasing Tauc band gap at increasing total hydrogen concentration—this allows to directly relate the band gap of amorphous silicon to the presence of nanovoids in the material.

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“…There exist important contributions of ions to the growth of a-Si:H and mc-Si films. [10][11][12][13][14][15][16] Substrate bias is a beneficial method for controlling the flux and energy of ions impinging on the growing surface. A moderate substrate bias increases the crystallinity and reduces the incubation layer thickness.…”

mentioning

confidence: 99%

“…Several studies have been conducted to clarify the effects of the substrate bias on a-Si:H and mc-Si depositions. [10][11][12][13][14][15][16] However, the results from these studies led to controversial conclusions regarding the effect of ion bombardment. A negative substrate bias was reported to increase the crystalline size and to reduce the incubation layer thickness of the mc-Si films.…”

mentioning

confidence: 99%

Enhanced Nucleation of Microcrystalline Silicon Thin Films Deposited by Inductively Coupled Plasma Chemical Vapor Deposition with Low-Frequency Pulse Substrate Bias

Furuta

Hiramatsu

Hirao

2010

Jpn. J. Appl. Phys.

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Microcrystalline silicon (µc-Si) films were deposited by inductively coupled plasma chemical vapor deposition with a low-frequency and low-duty pulse substrate bias (PSB). The crystallinity of the films was significantly improved by the PSB. In the case of the low-frequency and low-duty PSB, the duty ratio affected the crystallinity more than the negative peak voltage. Cross-sectional transmission electron microscopy measurements revealed that the nucleation density at the µc-Si/glass interface was increased by the PSB. This technique will be useful in fabricating high-performance bottom-gate µc-Si thin-film transistors for large-area electronics.

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Effects of substrate bias on structure and properties of a-Si:H films deposited by ECR microwave plasmas

Cited by 11 publications

References 5 publications

The energy distribution function of ions impinging on nanoparticles in a collisional low-pressure plasma

The energy distribution function of ions impinging on nanoparticles in a collisional low-pressure plasma

Hydrogenated amorphous silicon deposited under accurately controlled ion bombardment using pulse-shaped substrate biasing

Enhanced Nucleation of Microcrystalline Silicon Thin Films Deposited by Inductively Coupled Plasma Chemical Vapor Deposition with Low-Frequency Pulse Substrate Bias

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