Intentional Reconstruction of Silicon Network on the Surface and within Sub-Surface by H and Ar

1997 ◽  
Vol 467 ◽  
Author(s):  
W. Futako ◽  
K. Fukutani ◽  
I. Shimizu
Keyword(s):  
Thin Films ◽  
Glow Discharge ◽  
Thin Layer ◽  
Defect Density ◽  
Hydrogen Atoms ◽  
Silicon Thin Films ◽  
Chemical Annealing ◽  
Rf Glow Discharge ◽  
Wide Gap ◽  
The Stability

ABSTRACTSilicon thin films were prepared by “Chemical Annealing” where the deposition of thin layer (<3 nm thick) by RF glow discharge of SiH4 and the treatment with hydrogen atoms (H) or triplet state of argon (3Ar) were repeated alternatating. Consequently, wide gap a-Si:H with the gap of 2.1 eV was made by H-treatmentat rather low substrate temperature (Ts<150 °C), while a-Si:H with the gap narrower than 1.6 eV was obtained by the treatment with 3Ar at high Ts (>300 °C), resulting from the release of excessive hydrogen. Both the wider or the narrower gap films exhibited low defect density lower than 1016 cm−3 and obvious improvements in the stability for light soaking.

Relation Between Defect Density and Local Structures of a-Si:H

1995 ◽  
Vol 377 ◽  
Author(s):  
M. Azuma ◽  
K. Nakamura ◽  
T. Yokoi ◽  
K. Yoshino ◽  
I. Shimizu
Keyword(s):  
Local Structure ◽  
Atomic Hydrogen ◽  
Defect Density ◽  
In Situ Monitoring ◽  
High Quality ◽  
Local Structures ◽  
Chemical Annealing ◽  
Rf Glow Discharge ◽  
The Stability

ABSTRACTHigh quality a-Si:H thin films with varied optical gaps in the range from 1.55 to 2.1 eV were fabricated by various methods, i.e., the standard RF glow discharge of silane, “Chemical Annealing” and ECR-H-plasma from SiCl2H2 under in situ monitoring with an ellipsome try. Despite marked differences in the local structure, all these films showed low defect density as low as (3–5) × 1015 cm3. In addition, the stability for light soaking was improved markedly for the films made by promoting intensively structural relaxation with atomic hydrogen.

Preparation of Polycrystalline Silicon Thin Films by Cathode-Type RF Glow Discharge Method

1993 ◽  
Vol 32 (Part 1, No. 9A) ◽  
pp. 3729-3733 ◽  
Author(s):  
Ahalapitiya Hewage Jayatissa ◽  
Yoichiro Nakanishi ◽  
Yoshinori Hatanaka
Keyword(s):  
Thin Films ◽  
Glow Discharge ◽  
Polycrystalline Silicon ◽  
Silicon Thin Films ◽  
Rf Glow Discharge ◽  
Discharge Method

Optical Absorption in Co-Deposited Mixed-Phase Hydrogenated Amorphous/Nanocrystalline Silicon Thin Films

2010 ◽  
Vol 1245 ◽  
Author(s):  
Lee Wienkes ◽  
Aaron Besaw ◽  
Curtis Anderson ◽  
David Bobela ◽  
Paul Stradins ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Absorption ◽  
Absorption Spectra ◽  
Defect Density ◽  
Amorphous Material ◽  
Nanocrystalline Silicon ◽  
Esr Spectra ◽  
Hydrogenated Silicon ◽  
Silicon Thin Films ◽  
Electron Donation

AbstractThe conductivity of amorphous/nanocrystalline hydrogenated silicon thin films (a/nc-Si:H) deposited in a dual chamber co-deposition system exhibits a non-monotonic dependence on the nanocrystal concentration. Optical absorption measurements derived from the constant photocurrent method (CPM) and preliminary electron spin resonance (ESR) data for similarly prepared materials are reported. The optical absorption spectra, in particular the subgap absorption, are found to be independent of nanocrystalline density for relatively small crystal fractions (< 4%). For films with a higher crystalline content, the absorption spectra indicate broader Urbach slopes and higher midgap absorption. The ESR spectra show an approximately constant defect density across all of the films. These data are interpreted in terms of a model involving electron donation from the nanocrystals into the amorphous material.

Wide band gap amorphous silicon thin films prepared by chemical annealing

1999 ◽  
Vol 85 (2) ◽  
pp. 812-818 ◽  
Author(s):  
Wataru Futako ◽  
Kunihiko Yoshino ◽  
Charles M. Fortmann ◽  
Isamu Shimizu
Keyword(s):  
Thin Films ◽  
Amorphous Silicon ◽  
Band Gap ◽  
Wide Band ◽  
Wide Band Gap ◽  
Silicon Thin Films ◽  
Chemical Annealing

Density of States of Amorphous Germanium Thin Films Deposited by the Pecvd of H2-Diluted Germane

1990 ◽  
Vol 192 ◽  
Author(s):  
C. Godet ◽  
V. Chu ◽  
B. Equer ◽  
Y. Bouizem ◽  
L. Chahed ◽  
...  
Keyword(s):  
Thin Films ◽  
Density Of States ◽  
Surface Passivation ◽  
Defect Density ◽  
Level Density ◽  
Chemical Vapor ◽  
Optical Data ◽  
Hydrogen Atoms ◽  
Bond Density ◽  
Spin Measurements

ABSTRACTThe disorder in a-Ge:H thin films produced by the plasma-enhanced chemical vapor deposition (PECVD) technique is strongly reduced when the GeH4 gas is diluted at 1% in H2 and the radiofrequency power density is increased to 0.1 W.cm−2. This improvement is attributed to a better surface passivation by the hydrogen atoms during the growth. However, the poor transport properties indicate a still high defect density. The midgap defect absorption and the Urbach energy, obtained from the photothermal deflection spectra calibrated with optical data, both decrease as a function of the film thickness. The optical defect density is calibrated with EPR spin measurements. For a-Ge:H films thicker than 2 μm, obtained at a deposition temperature Ts ranging from 150 to 250°C, the Urbach tail parameter E° is lower than 50 meV and not sensitive to Ts ; the dangling bond density is around 4.107 cm−3, which is higher by a factor of 100 than in a-Si:H. Preliminary transport measurements indicate that the Fermi level density of states is larger than 1018 cm−3.eV−1.

The effects of the glass substrate on the properties of rf glow discharge amorphous Si:H thin films

1988 ◽  
Vol 63 (7) ◽  
pp. 2443-2445 ◽  
Author(s):  
Y.C. Koo ◽  
R. Perrin ◽  
K. T. Aust ◽  
S. Zukotynski ◽  
R. V. Kruzelecky
Keyword(s):  
Thin Films ◽  
Glow Discharge ◽  
Glass Substrate ◽  
Rf Glow Discharge
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