Deposition of microcrystalline silicon solar cells via the pulsed PECVD technique

Das, Ujjwal K.; Morrison, S.; Madan, A.

doi:10.1016/s0022-3093(01)00945-0

Cited by 9 publications

(3 citation statements)

References 3 publications

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“…Details on the deposition conditions, electrical property measurements of the samples, and the construction and assessment of simple solar cell structures are also documented elsewhere. 5,28 CAE was used to deposit the Cr -N graded coating system because of its advantages of high deposition and production rate, high ionisation of species (90 -100%) and high ion kinetic energy (50 -150 eV) compared with other PVD methods for depositing wear resistant thin films. The effects of high energy metal ion bombardment to the substrate/coating interface region were investigated by comparison of CAE Cr -N coatings on 7075-T6 aluminium at low temperatures (v120uC) with or without the assistance of a high energy (f30 keV) microsecond pulsing of the substrate using a Hyper-Ion system.…”

Section: Experimental Methodsmentioning

confidence: 99%

“…Amorphous to nanocrystalline silicon thin films were produced under both continuous wave (CW) and pulsed conditions using PECVD. Recent research 28,29 has shown that P-PECVD is capable of producing state of the art amorphous and nanocrystalline Si with a high deposition rate and a large gas utilisation rate coupled with a potential lower cost of production. Amorphous silicon (a-Si:H) films are normally deposited at the rate of 0 .…”

Section: Pulsed Reactive Sputtering Of Tio Thin Filmsmentioning

confidence: 99%

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Effect of Pulsed Plasma Processing on Controlling Nanostructure and Properties of Thin Film/Coatings

Zhong¹,

Mishra

Moore³

et al. 2004

Surface Engineering

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The benefits of pulsed plasma processing, including pulsing both cathode and substrate in physical vapour deposition (PVD) processes (magnetron sputtering and cathodic arc evaporation (CAE)) and the pulsed plasma enhanced chemical vapour deposition (P-PECVD) process were demonstrated by correlating the pulsed plasma process parameters, microstructure and properties. Five coating systems were developed for structural, electronic, functional and tribological applications. These are: pulsed reactive magnetron sputtering of TiO thin films; alumina deposition with pulsed plasma in closed field unbalanced magnetron sputtering; deposition of thin film silicon using P-PECVD; high energy pulsed bias assisted CAE of Cr -N graded coatings on 7075-T6 Al substrates; and sputter deposition of nickel anode on protonic BaCe 0 . 9 Y 0 . 1 O 3 -a electrolyte under pulsed dc biasing of substrate. Pulsed plasma was found to change particle energies and plasma composition in both PVD and CVD processes. Through controlled ion bombardment (ion energies and relative abundances of plasma species) by varying pulse frequency, pulse duration and bias voltage, film growth and therefore film properties can be tailored. The films became denser and nanostructured. The interface structure was graded, allowing superior adhesion. Better film performance (e.g. wear resistance, fracture toughness and efficiencies of solar cells and fuel cells) was achieved because of the modified film microstructure and architecture. These results clearly indicate the significant effects of the plasma species and their energies on modification of both the structure and properties of thin films. In several of these examples, the properties could not have been achieved in continuous dc magnetron sputtering. SE/518Drs Zhong, Mishra (bmishra@mines.edu) and Moore are in the Advanced Coatings and Surface Engineering Laboratory (ACSEL), Colorado School of Mines,

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Section: Experimental Methodsmentioning

confidence: 99%

Section: Pulsed Reactive Sputtering Of Tio Thin Filmsmentioning

confidence: 99%

Effect of Pulsed Plasma Processing on Controlling Nanostructure and Properties of Thin Film/Coatings

Zhong¹,

Mishra

Moore³

et al. 2004

Surface Engineering

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“…This feature enabled us to employ an extremely high dilution of monosilane by hydrogen, under which condition the nucleation process is strongly favored and thus the formation of incubation layers can be minimized. We also expect additional beneficial effects by pulsed operation of plasma, since a pulsed modulation has been claimed to have beneficial effects 5) for high rate productions in conventional low-pressure RF discharge. In this report, we describe the properties of the polycrystalline films obtained in our pulsed-discharge based PE-CVD system.…”

mentioning

confidence: 99%

Incubation-Free Growth of Polycrystalline Si Films by Plasma-Enhanced Chemical Vapor Deposition Using Pulsed Discharge under Near Atmospheric Pressure

Kitabatake

Suemitsu

Kitahata

et al. 2005

Jpn. J. Appl. Phys.

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One important problem in computational structural biology is protein designability, that is, why protein sequences are not random strings of amino acids but instead show regular patterns that encode protein structures. Many previous studies that have attempted to solve the problem have relied upon reduced models of proteins. In particular, the 2D square and the 3D cubic lattices together with reduced amino acid alphabet models have been examined extensively and have led to interesting results that shed some light on the evolutionary relationship among proteins. Here we perform designability studies on the 2D square lattice and explore the effects of variable overall shapes on protein designability using a binary hydrophobic-polar (HP) amino acid alphabet. Because we rely on a simple energy function that counts the total number of H-H interactions between non-sequential residues, we restrict our studies to protein shapes that have the same number of residues and also a constant number of non-bonded contacts. We have found that there is a marked difference in the designability between various protein shapes, with some of them accounting for a significantly larger share of the total foldable sequences.

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Effects of modulation frequency on the structure and electrical characteristics of μc-Si:H films prepared by pulsed VHF-PECVD

Wang

Zhang

Zhao

et al. 2009

Optoelectron. Lett.

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Modulation frequency and pulse duty cycle are two key parameters of pulsed VHF-PECVD technology. An experimental study on the microcrystalline silicon materials prepared by pulsed VHF-PECVD technology in high deposition rate is presented. And combining the diagnosis of plasma process with optical emission spectroscopy (OES), the dependence of microstructure and electrical properties of thin films on the pulse modulation frequency is discussed in detail.Recently the high-pressure VHF-PECVD with high input power [1,2] enables to achieve microcrystalline silicon thin film at high deposition rate. Meanwhile, the method will result in powder formation in the plasma, which deteriorates the quality of thin film. The deposition technology of microcrystalline silicon thin films by using pulsed PECVD method [3][4][5] can increase the deposition rate, and suppress dust formation. The 'on' and 'off' pulse modulation influences the chemical reactions in the plasma, and hence the high quality c-Si:H thin films and solar cells can be obtained [6][7][8] . In this paper, we study experimenally the effects of pulse modulation frequency on the structural, electrical characteristics and the growth rate of c -Si:H thin films.All c-Si:H thin films were prepared by using the Cluster CVD System with capacitive coupled plate electrodes at the background vacuum lower than 10 -5 Pa. The 70 MHz VHF power was modulated by square wave pulse at frequencies in the range 10 to 1000 kHz, with an 'on' time to 'off' time ratio of 80-90%. The dark and photo-currents of materials were measured by Keithley 617 at room temperature using Al coplanar contact electrode at dark condition and AM1.5 illumination, respectively, and then the conductivities were calculated. The crystalline volume fraction was evaluated by Raman scattering measurements. The glow of the plasma was monitored by optical emission spectroscopy (OES).As shown in Fig.1, the photo and dark conductivities of films prepared in the pulsed discharge at the modulation frequencies higher than 100 kHz almost maintain at the level of around 10 -4 s/cm and 10 -7 s/cm, respectively. At this circumstance, the pulse period is shorter than 10 ìs, especially the shorter off-time. Therefore, although plasma sheath collapses and the high temperature electron density drops rapidly a few ìs after the power is off [4] , the ions or radicals produced during the plasma on-time, especially the negative ions, have no time for their loss by ambipolar diffusion and by volume recombination and continue their production and Fig.1 Film conductivity and photosensitivity as a function of modulation frequency.

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Deposition of microcrystalline silicon solar cells via the pulsed PECVD technique

Cited by 9 publications

References 3 publications

Effect of Pulsed Plasma Processing on Controlling Nanostructure and Properties of Thin Film/Coatings

Effect of Pulsed Plasma Processing on Controlling Nanostructure and Properties of Thin Film/Coatings

Incubation-Free Growth of Polycrystalline Si Films by Plasma-Enhanced Chemical Vapor Deposition Using Pulsed Discharge under Near Atmospheric Pressure

Effects of modulation frequency on the structure and electrical characteristics of μc-Si:H films prepared by pulsed VHF-PECVD

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