In Situ Probing and Atomistic Simulation of a-Si:H Plasma Deposition

2001 ◽  
Vol 664 ◽  
Author(s):  
Eray S. Aydil ◽  
Dimitrios Maroudas ◽  
Denise C. Marra ◽  
W. M. M. Kessels ◽  
Sumit Agarwal ◽  
...  
Keyword(s):  
Plasma Deposition ◽  
Atomistic Simulations ◽  
Experimental Measurements ◽  
Supporting Evidence ◽  
Flat Panel Displays ◽  
Film Properties ◽  
Elementary Processes ◽  
Silicon Thin Films ◽  
Hydrogenated Amorphous

ABSTRACTHydrogenated amorphous silicon thin films deposited from SiH4 containing plasmas are used in solar cells and thin film transistors for flat panel displays. Understanding the fundamental microscopic surface processes that lead to Si deposition and H incorporation is important for controlling the film properties. An in situ method based on attenuated total internal reflection Fourier transform infrared (ATR-FTIR) spectroscopy was developed and used to determine the surface coverage of silicon mono-, di-, and tri-hydrides as a function of deposition temperature and ion bombardment flux. Key reactions that take place on the surface during deposition are hypothesized based on the evolution of the surface hydride composition as a function of temperature and ion flux. In conjunction with the experiments, the growth of a-Si:H on H-terminated Si(001)-(2×1) surfaces was simulated through molecular dynamics. The simulation results were compared with experimental measurements to validate the simulations and to provide supporting evidence for radical-surface interaction mechanisms hypothesized based on the infrared spectroscopy data. Experimental measurements of the surface silicon hydride coverage and atomistic simulations are used synergistically to elucidate elementary processes occurring on the surface during a-Si:H deposition.

Surface Processes during Growth of Hydrogenated Amorphous Silicon

2004 ◽  
Vol 808 ◽  
Author(s):  
Eray S. Aydil ◽  
Sumit Agarwal ◽  
Mayur Valipa ◽  
Saravanapriyan Sriraman ◽  
Dimitrios Maroudas
Keyword(s):  
Amorphous Silicon ◽  
Film Growth ◽  
Silicon Film ◽  
Hydrogenated Amorphous Silicon ◽  
Surface Processes ◽  
Atomistic Simulations ◽  
Elementary Surface ◽  
Hydrogenated Amorphous ◽  
And Diffusion

ABSTRACTHydrogenated amorphous silicon films for photovoltaics and thin film transistors are deposited from silane containing discharges. The radicals generated in the plasma such as SiH3 and H impinge on the surface and lead to silicon film growth through a complex network of elementary surface processes that include adsorption, abstraction, insertion and diffusion of various radicals. Mechanism and kinetics of these reactions determine the film composition and quality. Developing deposition strategies for improving the film quality requires a fundamental understanding of the radical-surface interaction mechanisms. We have been using in situ multiple total internal reflection Fourier transform infrared spectroscopy and in situ spectroscopic ellipsometry in conjunction with atomistic simulations to determine the elementary surface reaction and diffusion mechanisms. Synergistic use of experiments and atomistic simulations elucidate elementary processes occurring on the surface. Herein, we review our current understanding of the reaction mechanisms that lead to a-Si:H film growth with special emphasis on the reactions of the SiH3 radical.

Plasma Deposition and Characterization of Stable a-Si:H (Cl) From a Silane-Dichlorosilane Mixture

1995 ◽  
Vol 377 ◽  
Author(s):  
I. S. Osborne ◽  
N. Hata ◽  
A. Matsuda
Keyword(s):  
Defect Density ◽  
Plasma Deposition ◽  
Chemical Vapor ◽  
Mixing Ratio ◽  
Film Properties ◽  
Laser Illumination ◽  
Induced Defects ◽  
Hydrogenated Amorphous

ABSTRACTHydrogenated amorphous silicon containing chlorine (a-Si:H (Cl)) films have been grown by plasma enhanced chemical vapor deposition from a mixture of silane and dichlorosilane with a dichlorosilane concentration up to 60%. We report on the film properties in the as-deposited state and the behavior of the films under both high intensity pulsed laser illumination and long-term AMI illumination. With increasing dichlorosilane concentration the films show an increased resilience to the creation of light induced defects, as determined from the constant photocurrent method. After 900 hours under AMI illumination, the defect density shows a minimum (< 1016 cnr−3) for a 10 % mixing ratio.

Determination of Interface and Surface Structure During the Growth of a-Si:H-Based Heterostructures

1987 ◽  
Vol 95 ◽  
Author(s):  
R. W. Collins ◽  
J. M. Cavese
Keyword(s):  
Growth Models ◽  
Spectroscopic Studies ◽  
Film Properties ◽  
Surface And Interface ◽  
Before And After ◽  
Interface Layers ◽  
Hydrogenated Amorphous ◽  
Planar Growth

AbstractEllipsometry measurements of hydrogenated amorphous silicon (a-Si:H)-based heterostructures have been used to characterize surfaces and single interfaces. From spectroscopic studies before and after plasma oxidation of a-Si:H, surface roughness on the atomic scal; (in the plane of the surface) can be distinguished from larger scale (> 100 Å) modulation. We also show how in situ studies of heterostructure preparation can be used to set deposition conditions to minimize near-interface layers owing to thickness dependent film properties. When these are eliminated, the discrepancies in the data from planar layer-bylayer growth models can be attributed to the larger scale surface and interface modulation. Finally, extensive deviations from planar growth for a-Si:H/μc-Si:H have been characterized in terms of specific heterogeneities.

In-Situ Excimer Laser Induced Crystallization of Hydrogenated Amorphous Silicon Thin Films

1994 ◽  
Vol 37-38 ◽  
pp. 281-286 ◽  
Author(s):  
N. Layadi ◽  
Pere Roca i Cabarrocas ◽  
J. Huc ◽  
J.-Y. Parey ◽  
B. Drévillon
Keyword(s):  
Thin Films ◽  
Amorphous Silicon ◽  
Excimer Laser ◽  
Hydrogenated Amorphous Silicon ◽  
Silicon Thin Films ◽  
Hydrogenated Amorphous ◽  
Induced Crystallization

Deposition and Crystallisation Behaviour of Amorphous Silicon Thin Films Obtained by Pyrolysis of Disilane Gas at Very Low Pressure

1994 ◽  
Vol 345 ◽  
Author(s):  
T. Kretz ◽  
D. Pribat ◽  
P. Legagneux ◽  
F. Plais ◽  
O. Huet ◽  
...  
Keyword(s):  
Activation Energy ◽  
Growth Rate ◽  
Amorphous Silicon ◽  
Vapor Deposition ◽  
Electrical Conductance ◽  
Chemical Vapor ◽  
Crystalline Fraction ◽  
Silicon Thin Films ◽  
Crystallisation Behaviour

AbstractHigh purity amorphous silicon layers were obtained by ultrahigh vacuum (millitorr range) chemical vapor deposition (UHVCVD) from disilane gas. The crystalline fraction of the films was monitored by in situ electrical conductance measurements performed during isothermal annealings. The experimental conductance curves were fitted with an analytical expression, from which the characteristic crystallisation time, tc, was extracted. Using the activation energy for the growth rate extracted from our previous work, we were able to determine the activation energy for the nucleation rate for the analysed-films. For the films including small crystallites we have obtained En ∼ 2.8 eV, compared to En ∼ 3.7 eV for the completely amorphous ones.

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