Bond-Angle Variation and Microstructure in Hydrogenated Amorphous Silicon

1992 ◽  
Vol 258 ◽  
Author(s):  
A. J. M. Berntsen ◽  
M. J. Van Den Boogaard ◽  
W. G. J. H. M. Van Sark ◽  
W. F. Van Der Weg
Keyword(s):  
Substrate Temperature ◽  
Amorphous Silicon ◽  
Bond Angle ◽  
Hydrogenated Amorphous Silicon ◽  
Structural Disorder ◽  
Angle Variation ◽  
Model Calculations ◽  
Scattering Measurements ◽  
Rf Glow Discharge ◽  
Hydrogenated Amorphous

ABSTRACTA series of hydrogenated amorphous silicon (a-Si:H) films was deposited by rf glow-discharge deposition using various processing conditions. We have studied microstructure in the films by means of infrared absorption spectroscopy. Small-angle X-ray scattering measurements were used to determine the microvoid fractions of a few selected samples. Our results show that both the void fraction and the amount of microstructure can be varied either by changing the substrate temperature or by H2 dilution. Bond-angle variation in the films was probed by Raman scattering measurements. The Raman data indicate that the substrate temperature is the main variable that determines the bond-angle variation. We conclude that the presence of microvoids in a-Si:H does not influence the structural disorder of the amorphous matrix surrounding the voids. Our results are in agreement with experimental work on microvoids in a-Si1-xCx:H, and model calculations on voids in a-Si.

Annealing of Ion-Implanted Hydrogenated Amorphous Silicon: Stable and Removable Damage

1993 ◽  
Vol 297 ◽  
Author(s):  
A.J.M. Berntsen ◽  
P.A. Stolk ◽  
W.F. VAN DER WEG ◽  
F.W. Saris
Keyword(s):  
Amorphous Silicon ◽  
Structural Changes ◽  
Hydrogenated Amorphous Silicon ◽  
Structural Disorder ◽  
High Dose ◽  
Angle Variation ◽  
Reflection And Transmission ◽  
Hydrogenated Amorphous ◽  
Average Bond ◽  
High Dose Implantation

Hydrogenated amorphous silicon (a-Si:H) films were irradiated with 1-MeV Si+ ions. The accumulation and annealing of ion damage was investigated by Raman scattering, optical reflection and transmission, and conductivity measurements. For damage levels up to 0.003 displacements per atom, electrical defects are created with no measurable effect on the structural properties. These defects can be completely annealed out at 180°C. Further irradiation results in an increase in the average bond-angle variation in the films. This structural disorder causes a decrease of the optical band gap with 0.46 eV. The structural changes caused by high-dose implantation can not be reversed by annealing at 180° C, which results in the formation of anneal-stable electrical defects.

Substrate temperature effect on the stability of hydrogenated amorphous silicon films deposited at high rates

1995 ◽  
Vol 78 (1) ◽  
pp. 317-320 ◽  
Author(s):  
J. P. Kleider ◽  
C. Longeaud ◽  
M. Barranco‐Diaz ◽  
P. Morin ◽  
P. Roca i Cabarrocas
Keyword(s):  
Substrate Temperature ◽  
Temperature Effect ◽  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Silicon Films ◽  
The Stability ◽  
Hydrogenated Amorphous

Modulation of Growing Surface with Atomic Hydrogen and Excited Argon to Fabricate Narrow Gap a-Si:H

1996 ◽  
Vol 420 ◽  
Author(s):  
W. Futako ◽  
I. Shimizu ◽  
C. M. Fortmann
Keyword(s):  
Thin Layer ◽  
Substrate Temperature ◽  
Amorphous Silicon ◽  
Atomic Hydrogen ◽  
Hydrogenated Amorphous Silicon ◽  
High Substrate Temperature ◽  
Narrow Gap ◽  
High Quality ◽  
Chemical Annealing ◽  
Hydrogenated Amorphous

AbstractHydrogenated amorphous silicon (a-Si:H) with a gaps narrower than 1.7 eV were made by repeating the deposition of a thin layer (1–3 nm thick) and the treatment of growing surface with a mixture of H and Ar*. Crystallization induced by permeation of hydrogen into the subsurface at high substrate temperature (>200C) was efficiently prevented by treating with a mixture of H and Ar*. The activation of growing surface may arise from releasing a part of hydrogen on surface by treating with Ar*. High quality a-Si:H films containing hydrogen of 3 atom % with a gap of 1.6 eV were made by chemical annealing with a mixture of H and Ar*.

Growth and Characterization of Hydrogenated Amorphous Silicon using Liquid Organic Sources

1991 ◽  
Vol 219 ◽  
Author(s):  
K. Gaughan ◽  
S. Hershgold ◽  
J. M. Viner ◽  
P. C. Taylor
Keyword(s):  
Thin Films ◽  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Wide Band ◽  
Discharge Process ◽  
Wide Band Gap ◽  
Silicon Carbon ◽  
Rf Glow Discharge ◽  
Hydrogenated Amorphous

ABSTRACTThe uses of liquid sources such as tertiarybutylphosphine (TBP) for n-type doping in hydrogenated amorphous silicon (a-Si:H) and ditertiarybutylsilane (DTBS) and n-butylsilane (NBS) for hydrogenated amorphous silicon-carbon alloys (a-SiC:H) are described. A rf glow discharge process is employed to produce the doped a-Si:H and a-SiC:H thin films. Tertiarybutylphosphine (TBP) may ultimately be preferred over phosphine because TBP is less toxic, less pyrophoric and safer to implement. The gross doping properties of a-Si:H doped with TBP are the same as those obtained with phosphine, but there are some differences. N-butylsilane (NBS) and DTBS have been used to produce wide band gap (E04 3 ≈ eV) a-SiC:H.

The Dependence of ECR-CVD Processing Parameters on Deposition Uniformity of Hydrogenated Amorphous Silicon (a-Si:H) Films

2015 ◽  
Vol 656-657 ◽  
pp. 92-100
Author(s):  
Li Cheng Hu ◽  
Yong Shiang Li ◽  
Chien Chieh Lee ◽  
Jeng Yang Cheng ◽  
I Chen Chen ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Substrate Temperature ◽  
Amorphous Silicon ◽  
Microwave Power ◽  
Hydrogenated Amorphous Silicon ◽  
Processing Parameters ◽  
High Deposition Rate ◽  
Working Pressure ◽  
Deposition Uniformity ◽  
Hydrogenated Amorphous

The uniformity improvement of high deposition rate in hydrogenated amorphous silicon (a-Si:H) film deposited by electron cyclotron resonance chemical vapor deposition (ECR-CVD) is very essential for a large substrate in PV solar industry. In order to improve the uniformity in depositing thin film in large area, the auxiliary magnetic coils were designed and installed in ECR-CVD to modify the distribution of magnetic field. In addition, the dependence of the other ECR-CVD processing parameters such as resonance position, microwave power, working pressure, and substrate temperature were investigated. The results indicated that more uniform a-Si:H film could be obtained when working pressure was decreased. By using finite element analysis, it was found that location of turbo pump would impact gas flow field and this effect would become more significant at high pressure. Increasing microwave power, increasing horizontal gradient of the magnetic field to the substrate, and forming Cusp magnetic field could enhance ECR-CVD deposition uniformity greatly. However, the plasma location and substrate temperature were not major factors affecting a-Si:H film uniformity in ECR-CVD process. Finally, the optimal and the best 3.8% in uniformity could be achieved in 150mm diameter when the ratio of magnetic field strength at wafer edge to wafer center is 215%, working pressure is 1.5 mtorr, microwave power density is 4W/cm2, and substrate temperature is 180°C.

Percolation Behaviour in the Electrical Characteristics of Hydrogenated Amorphous Silicon Nitride Films.

1992 ◽  
Vol 258 ◽  
Author(s):  
J.M. López-Villegas ◽  
B. Garrido ◽  
M.S. Benrakkad ◽  
J. Samitier ◽  
E. Bertran ◽  
...  
Keyword(s):  
Silicon Nitride ◽  
Amorphous Silicon ◽  
Photoelectron Spectroscopy ◽  
Hydrogenated Amorphous Silicon ◽  
Electrical Characteristics ◽  
Amorphous Silicon Nitride ◽  
Silicon Nitride Films ◽  
Rf Glow Discharge ◽  
Ohmic Conductivity ◽  
Hydrogenated Amorphous

ABSTRACTThe electro-optical properties of hydrogenated amorphous silicon nitride films (a-SiNx:H) prepared by rf glow discharge of SiH4 and N2 have been determined as a function of the silicon content in the alloy. The stoichiometry and structure of the layers have been studied by ellipsometry, infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Two different electrical behaviours have been found. The samples with x>0.8 show conductivity based on the Frenkel-Poole mechanism, while the samples with x<0.8 show quasi-ohmic conductivity. Both kinds of conduction and the transition between them are analyzed in the framework of the percolation theory. In this context, the correlation between the stoichiometry and structure of the layers with their electrical behaviour indicate that the transition from the Frenkel-Poole to the quasi-ohmic conduction is a consequence of the formation of conducting paths as the percolation threshold of Si-Si bonds is reached.

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