A combinatorial analysis of deposition parameters on deposition process and performance of silicon thin films by VHF-PECVD

AbstractPolycrystalline silicon thin films that are permeable to fluids, known as permeable polysilicon, have been reported by several researchers. Such films have great potential for the fabrication of difficult to make MEMS structures, but their use has been hampered by poor process repeatability and a lack of physical understanding of the origin of film permeability and how to control it. We have completed a methodical study of the relationship between process, microstructure, and properties for permeable polysilicon thin films. As a result, we have determined that the film permeability is caused by the presence of nanoscale pores, ranging from 10-50 nm in size, that form spontaneously during LPCVD deposition within a narrow process window. The unusual microstructure within this process window corresponds to the transition between a semicrystalline growth regime, exhibiting tensile residual stress, and a columnar growth regime exhibiting compressive residual stress. A simple kinetic model is proposed to explain the unusual morphology within this transition regime. It is determined that measurements of the film residual stress can be used to tune the deposition parameters to repeatably produce permeable films for applications. The result is a convenient, single-step process that enables the elegant fabrication of many previously challenging structures.

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Amorphous and nc-Si:H Intrinsic Thin Films for Solar Cells Applications

Materials Science Forum ◽

10.4028/www.scientific.net/msf.657.191 ◽

2010 ◽

Vol 657 ◽

pp. 191-207

Author(s):

Sylvain Halindintwali ◽

Dirk Knoesen ◽

Basil A. Julies ◽

Theo Muller ◽

Christopher J. Arendse

Keyword(s):

Thin Films ◽

Solar Cells ◽

Thermal Activation ◽

Chemical Vapour ◽

Deposition Process ◽

Silicon Thin Films ◽

Chemical Vapour Deposition Technique ◽

Structural And Electrical Properties ◽

Uv Visible

This contribution discusses the deposition process and properties of intrinsic silicon thin films processed by the hot wire chemical vapour deposition technique. We review some fundamental characterization techniques that are used to probe into the quality of the material and thus decide its susceptibility to be used as the intrinsic layer in solar cells industry. This paper covers the optical, structural and electrical properties of the material. Results from UV-visible and IR spectroscopy, XRD and Raman scattering, X-section TEM as well as dark and photo-currents are given. It is shown that the thermal activation energy is a good measure of the quality of the sample.

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¼c Silicon Thin Films Deposited by Remote Plasma Enhanced Chemical Vapor Deposition Process

MRS Proceedings ◽

10.1557/proc-192-535 ◽

1990 ◽

Vol 192 ◽

Cited By ~ 5

Author(s):

C. Wang ◽

G. N. Parsons ◽

S. S. Kim ◽

E. C. Buehler ◽

R. J. Nemanich ◽

...

Keyword(s):

Thin Films ◽

Chemical Vapor ◽

Deposition Process ◽

Substrate Material ◽

Degree Of Crystallinity ◽

Silicon Thin Films ◽

Hydrogen Dilution ◽

Type C ◽

Si Films ◽

P Type

ABSTRACTIn an earlier study, we deposited ¼c-Si thin films by reactive magnetron sputtering (RMS). Here we extend our studies to the deposition of both undoped and high conductivity N-type and P-type ¼c-Si thin films by a remote PECVD. We show that ¼c-Si films can be deposited by bringing hydrogen, H2, into the source gas mixtures. The H2 could introduced by either upstream in a He/H2 mixture and directly plasma excited, or downstream, and be remotely excited along with the silane, SiH4, feed gas. The degree of crystallinity is shown to depend on the hydrogen dilution, the substrate temperature and the substrate material.

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Elastic Properties of Diamond Like Carbon Thin Films: a Brillouin Scattering Study

MRS Proceedings ◽

10.1557/proc-444-93 ◽

1996 ◽

Vol 444 ◽

Cited By ~ 2

Author(s):

O. R. Monteiro ◽

I. G. Brown ◽

R. Sooryakumar ◽

M. Chirita

Keyword(s):

Thin Films ◽

Mechanical Properties ◽

Elastic Constants ◽

Brillouin Scattering ◽

Deposition Process ◽

Hard Coatings ◽

Vacuum Arc ◽

Deposition Parameters ◽

Scattering Study ◽

Isotropic Solids

AbstractDiamondlike carbon (DLC) thin films have been widely used as hard coatings in a variety of applications where increased wear resistance and hardness are required. Vacuum arc DLC films are among the hardest, with measured hardness values of up to 68 GPa. In our deposition process a repetitively pulsed bias voltage is applied to the substrate, which controls the energy of the incoming C ions. DLC chemical and mechanical properties are strongly affected by the energy of the depositing ions. In this paper, we relate the mechanical properties of these films to the deposition parameters, and describe our initial Brillouin scattering measurements of the elastic constants of monolithic DLC films. Evidence for bulk longitudinal and surface Rayleigh excitation in films with thickness of 50 and 500 nm has been observed. Since the DLC films are amorphous, they are modeled as isotropic solids and the elastic constants CII and C44 are derived.

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Microcrystalline Silicon Thin Films and Triple-Junction Solar Cells

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.468-471.1912 ◽

2012 ◽

Vol 468-471 ◽

pp. 1912-1915

Author(s):

Hui Zhi Ren ◽

Ying Zhao ◽

Xiao Dan Zhang ◽

Hong Ge ◽

Zong Pan Wang

Keyword(s):

Thin Films ◽

Solar Cells ◽

Triple Junction ◽

Microcrystalline Silicon ◽

Large Area ◽

High Quality ◽

Area Efficiency ◽

Silicon Thin Films ◽

Deposition Parameters ◽

Area Deposition

We report on microcrystalline silicon thin films and a-Si:H/a-SiGe:H/μc-Si:H triple-junction p-i-n solar cells deposited on large-area glass substrate. Microcrystalline silicon (μc-Si:H) bottom cells were deposited at a VHF-PECVD deposition system with 40.68MHz. It is necessary to develop the uniformity of μc-Si:H thin films for large-area deposition of high-quality triple-junction solar cells. By optimizing the deposition parameters, μc-Si:H thin films have been obtained with good thickness and very good crystalline volume fractions uniformity over the whole substrates area. The triple-junction module have been successful fabricated. The best module on 0.79 m2 size substrates has an initial total-area efficiency of 8.35%.

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Enhanced Crystallinity of Microcrystalline Silicon Thin Films Using Deuterium in Reactive Magnetron Sputter Deposition at 230°C

MRS Proceedings ◽

10.1557/proc-507-429 ◽

1998 ◽

Vol 507 ◽

Cited By ~ 4

Author(s):

J. E. Gerbi ◽

P. Voyles ◽

J. M. Gibson ◽

O J. R. Abelson

Keyword(s):

Thin Films ◽

Magnetron Sputtering ◽

Deposition Process ◽

Reactive Magnetron Sputtering ◽

Reactive Magnetron ◽

Glass Substrates ◽

Silicon Thin Films ◽

Partial Pressures ◽

Magnetron Sputter Deposition ◽

Enhanced Crystallinity

ABSTRACTWe analyze the formation kinetics and microstructure of hydrogenated vs. deuterated microcrystalline (μc-Si:H or D) thin films using real-time spectroscopic ellipsometry, post- deposition thermal hydrogen evolution, and TEM. The films are deposited by reactive magnetron sputtering of a silicon target in Ar (1.65 mT) with added partial pressures of H2or D2(0-5.5mT) on Coming 7059 glass substrates at 230°C. Amorphous films are deposited when PH2=0. When hydrogen is added to the chamber, the reactive magnetron sputtering process generates a flux of fast neutral H which promotes stc-Si growth. The substitution of D for H varies the kinetics of hydrogen reflection from the target and implantation into the growing film. We analyze the amorphous to microcrystalline transition as a function of the isotope (H2or D2) and pressure used in the deposition process. We find that the films enter the microcrystalline regime at lower D2pressures than H2pressures. Furthermore, the <ε2> data determined by ellipsometry have a different shape for deuterated films, compared to hydrogenated films at similar growth pressures. This indicates changes in band structure which we interpret as evidence for enhanced crystallinity.

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SILICON THIN FILMS PREPARED BY PECVD USING VHF POWER IN A CIRCULAR-PARALLEL-PLATE PLASMA REACTOR

International Journal of Modern Physics B ◽

10.1142/s0217979210056517 ◽

2010 ◽

Vol 24 (22) ◽

pp. 4209-4216 ◽

Cited By ~ 1

Author(s):

SHUTANG WEN ◽

YU MIAO ◽

YUNHUI WANG ◽

LIWEI ZHANG ◽

JINGXIAO LU ◽

...

Keyword(s):

Thin Films ◽

Deposition Rate ◽

Plasma Reactor ◽

Excitation Frequency ◽

Pulse Frequency ◽

Pulsed Power ◽

Silicon Thin Films ◽

Deposition Parameters ◽

Si Films ◽

Highly Uniform

The deposition rate of μc-Si films was investigated for four excitation frequencies 30, 40, 60, 70 and 80 MHz with other deposition parameters fixed. Deposition rate increases with the increasing of excitation frequency, while Raman crystallinity behaves more complicated. With the optimization of deposition parameters, p-i-n solar cells at an initial efficiency of 5.41% were fabricated. With the increasing of plasma excitation frequency, the non-uniformity of these thin films increases. To better understand the cause of the non-uniformity of these films, a numerical simulation was carried out. The numerical results generally followed the experimental data. It turned out that the standing waves and the evanescent wave guide modes on the electrode surface played an important role. In order to achieve highly uniform thin films, a triode-electrode was employed together with a pulsed power source. We found that with a proper choice of pulse frequency and DC voltage applied to the mesh, non-uniformity is less than 8% for films deposited on 10×10 cm 2 substrates. Simulations were also applied to analyze the results.

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Effect of Deposition Parameters on the Reactivity of Al/Ni Multilayer Thin Films

Coatings ◽

10.3390/coatings10080721 ◽

2020 ◽

Vol 10 (8) ◽

pp. 721

Author(s):

Ana Sofia Ramos ◽

Sónia Simões ◽

Lukasz Maj ◽

Jerzy Morgiel ◽

Maria Teresa Vieira

Keyword(s):

Thin Films ◽

Intermetallic Phase ◽

Ion Bombardment ◽

Deposition Process ◽

Phase Identification ◽

Multilayer Thin Films ◽

Substrate Bias ◽

X Ray Diffraction ◽

Deposition Parameters ◽

Transmission Electron

Nanoscale multilayers can be used as highly localized heat sources, making them attractive for several applications, in particular for joining and as igniters. Over the last decades, academia and industry have given particular emphasis to nanoscale multilayers from the Ni–Al system. In this study, Al/Ni (V) multilayer thin films with periods of nominally 25 and 50 nm (bilayer thickness) and near equiatomic average stoichiometry were produced by d.c. magnetron sputtering from Al (99.999% pure) and Ni (93 wt % Ni, 7 wt % V) targets (vanadium was added to the Ni target to make it non-magnetic). Deposition parameters such as the substrate rotation speed and substrate bias were varied in order to evaluate their effect on the reactivity of the multilayers. The influence of in situ ion bombardment of the multilayer thin films was also studied. Phase identification was carried out by X-ray diffraction, while the microstructure was analyzed in detail by transmission electron microscopy, distinguishing alternating layers throughout the entire thickness of the films. Although the films mainly consist of Al- and Ni-rich layers, the presence of the Al3Ni intermetallic phase was detected, except in the multilayers produced with the ion gun switched on during the deposition process. The ion bombardment, as well as the increase of the substrate bias, promote some microstructural disorder and thus affect the multilayers’ reactivity.

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The features of Ni2MnIn polycrystalline Heusler alloy thin films formation by pulsed laser deposition

Open Engineering ◽

10.1515/eng-2021-0019 ◽

2020 ◽

Vol 11 (1) ◽

pp. 227-232

Author(s):

Grunin Aleksei ◽

Maksimova Ksenia ◽

Goikhman Aleksander

Keyword(s):

Thin Films ◽

Heusler Alloy ◽

Growth Parameters ◽

Structural Phase ◽

Heusler Alloys ◽

Deposition Process ◽

High Energy ◽

Martensitic Transition ◽

Growth Pressure ◽

Deposition Parameters

AbstractThe Ni-Mn-In-based Heusler alloys belong to the most studied intermetallic compounds due to a variety of physical effects inherent to them, including the shape memory and magnetocaloric effect, field-induced structural phase transition, and others. All of these properties are strongly depend on element concentrations, uniformity, and purity of the structure. Therefore, rather strict requirements are imposed on the synthesis technology of such samples.We report the dependencies of Ni-Mn-In polycrystalline thin film composition on growth parameters. It was shown that the composition mismatch between sample and target caused by the resputtering of the sample material with high-energy particles of the ablation plume, and the different ablation yields of elements from the target. The main deposition parameters demonstrated (Ar growth pressure, laser energies, substrate temperature and annealing, target-to-sample distance) for the co-deposition process to obtain the Ni-Mn-In Heusler alloy polycrystalline thin films with the martensitic transition.

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