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Journal ArticleDOI

An Investigation of the Influence of Plasma Characteristics on the Electronic and Optical Properties of Device Quality a-Si:H Grown by Electron Cyclotron Resonance Plasma Deposition

01 Jan 1991-MRS Proceedings (Springer Science and Business Media LLC)-Vol. 219, Iss: 1, pp 781-786
TL;DR: In this paper, the electronic and optical properties of device quality hydrogenated amorphous silicon (a-Si:H) films grown by electron cyclotron resonance (ECR) plasma deposition were studied together with in-situ plasma characteristics.
Abstract: The electronic and optical properties of device quality hydrogenated amorphous silicon (a-Si:H) films grown by electron cyclotron resonance (ECR) plasma deposition were studied together with in-situ plasma characteristics. Hydrogen and helium plasmas, excited by 50-250 watts of 2.45 GHz microwave power under ECR conditions, were used to decompose silane at 6 to 20 mtorr pressures during the deposition of a-Si:H films at a 297 C substrate temperature. Both the electron temperature and density, and ion flux are measured near the deposition surface using plane and cylindrical Langmuir probes. An attempt is made to correlate these plasma properties with the light and dark photoconductivity, optical gap, refractive index, and subband gap photoconductivity.
Citations
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Journal ArticleDOI
TL;DR: Molecular dynamics simulations of the deposition of atomic H on both cSi and aSi:H substrates are performed to understand the physical processes occurring in the presence of an atomic H flux during growth as mentioned in this paper.
Abstract: Molecular dynamics simulations of the deposition of atomic H on both c‐Si and a‐Si:H substrates are performed to understand the physical processes occurring in the presence of an atomic H flux during growth The absorption probability, and dynamical behavior of the H are studied as a function of the incident H energy Both hydrogen absorption and backscattering events are observed The hydrogen reflection probability has a maximum around 50 eV and decreases at higher incident kinetic energies In the hydrogen backscattering events a substantial subsurface penetration and energy transfer through collisions are observed Hydrogen absorption events have been closely analyzed and a surface hydrogen release event was observed during an absorption event

8 citations

References
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Journal ArticleDOI
TL;DR: In this article, the optical constants of amorphous Ge were determined for the photon energies from 0.08 to 1.6 eV, and the absorption is due to k-conserving transitions of holes between the valence bands as in p-type crystals.
Abstract: The optical constants of amorphous Ge are determined for the photon energies from 0.08 to 1.6 eV. From 0.08 to 0.5 eV, the absorption is due to k-conserving transitions of holes between the valence bands as in p-type crystals; the spin-orbit splitting is found to be 0.20 and 0.21 eV in non-annealed, and annealed samples respectively. The effective masses of the holes in the three bands are 0.49 m (respectively 0.43 m); 0.04 m, and 0.08 m. An absorption band is observed below the main absorption edge (at 300 °K the maximum of this band is at 0.86 eV); the absorption in this band increases with increasing temperature. This band is considered to be due to excitons bound to neutral acceptors, and these are presumably the same ones that play a decisive role in the transport properties and which are considered to be associated with vacancies. The absorption edge has the form: ω2ϵ2∼(hω−Eg)2 (Eg = 0.88 eV at 300 °K). This suggests that the optical transitions conserve energy but not k vector, and that the densities of states near the band extrema have the same energy-dependence as in crystalline Ge. A simple theory describing this situation is proposed, and comparison of it with the experimental results leads to an estimate of the localization of the conduction-band wavefunctions.

8,184 citations

Journal ArticleDOI
TL;DR: In this article, a general trend of increasing defect density with atomic weight of the inert gas is observed, and the observation that high deposition rates can be achieved concurrently with low defect densities when helium is used as a deluent.
Abstract: Electrical, optical, and structural characterization of hydrogenated amorphous silicon films plasma‐deposited from mixtures of SiH4 with different inert‐gas diluents reveals substantial differences in a number of properties. A general trend of increasing defect density with atomic weight of the inert gas is observed. Of specific interest to device applications is the observation that high deposition rates can be achieved concurrently with low defect densities when helium is used as a deluent.

163 citations

Journal ArticleDOI
TL;DR: In this article, a high absorption level of microwave power (>95%) was achieved in all explored chambers at microwave power P=300-1000 W. The shape and location of the high plasma density area was determined by microwa...
Abstract: Electron cyclotron resonance plasmas were excited at a frequency of 2.45 GHz in chambers with diameters smaller and larger than cutoff ones for fundamental TE and TM modes. Microwaves were introduced in the plasma chambers from the cw generator via a vacuum window and the microwave transmission line. It was found that microwave breakdowns at pressures 10−5–10−1 Torr (argon, nitrogen, oxygen) occurred at sites where the static magnetic field was 875 G (or close). In chambers with diameter smaller than cutoff, the breakdown occurred only near the vacuum window. A high absorption level of microwave power (>95%) was achieved in all explored chambers at microwave power P=300–1000 W. It occurred at areas where the static magnetic field was ∼875 G and the plasma density was Ncr=7.4×1010 cm−3. A high microwave power absorption level resulted in high plasma density up to Ne=1012 cm−3 at P=1000 W. No saturation in Ne=f(P) was observed. The shape and location of the high plasma density area was determined by microwa...

85 citations

01 Jan 1986
TL;DR: The 1986 Materials Research Society Symposium on Materials Aspects of Amorphous Semicondcutor Technology as discussed by the authors was held in Palo Alto, California from April 15 through April 18.
Abstract: This volume represents the Proceedings of the 1986 Materials Research Society Symposium on Materials Aspects of Amorphous Semicondcutor Technology, held in Palo Alto, California from April 15 through April 18. The size of the volume, consisting of over 100 papers and filling more than 700 pages, yields an accurate picture of present interest in the field. The major interest in materials was localized to silicon alloys, although chalcogenides also received some attention. The device area reflected this bias in materials research.

45 citations

01 Jan 1989
TL;DR: In this paper, the authors discuss structural, electronic and optical properties of thin-film transistors, solar cells, photoreceptors and particle detectors, as well as stability of materials and devices and multilayers and interfaces.
Abstract: These proceedings contain papers on film growth; on fundamental studies of structural, electronic and optical properties; on devices such as thin film transistors, solar cells, photoreceptors and particle detectors; on amorphous semiconducting alloys; on stability of materials and devices; and on multilayers and interfaces.

42 citations