Probing the Elementary Surface Reactions of Hydrogenated Silicon PECVD by In-situ ESR

1998 ◽  
Vol 536 ◽  
Author(s):  
Satoshi Yamasaki ◽  
Claus Malten ◽  
Takehide Umeda ◽  
Jun-Ichi Isoya ◽  
Kazunobu Tanaka
Keyword(s):  
Gas Phase ◽  
Dynamic Change ◽  
Surface Region ◽  
Dangling Bond ◽  
Hydrogenated Silicon ◽  
Plasma Treatments ◽  
Elementary Surface ◽  
Ar Plasma ◽  
Hydrogenated Amorphous

AbstractThe dynamic change of the dangling bond (db) intensity in hydrogenated amorphous silicon (a-Si:H) during H2 and Ar plasma treatments was observed using an in-situ electron-spinresonance (ESR) technique. The experimental results show that the time to reach the steady state between gas-phase H atoms and the a-Si:H surface is less than 1 sec, and Ar plasma treatments create a top-surface region with an extremely high db density.

Real-Time ESR Observation During Film Growth of a-Si:H

1997 ◽  
Vol 467 ◽  
Author(s):  
S. Yamasaki ◽  
T. Umeda ◽  
J. Isoya ◽  
K. Tanaka
Keyword(s):  
Gas Phase ◽  
Film Growth ◽  
Hydrogen Plasma ◽  
Bulk Region ◽  
Dangling Bond ◽  
Dynamic Changes ◽  
Spin Resonance ◽  
Higher Spin ◽  
Hydrogenated Amorphous

ABSTRACTIn-situ electron-spin-resonance (ESR) measurements of film growth of hydrogenated amorphous silicon (a-Si:H) using a remote hydrogen plasma technique have been performed. The Si dangling-bond signal in a-Si:H during and after deposition has been detected, in addition to the gas-phase ESR signals both of atomic hydrogen and photo-excited SiHx molecules. Dynamic changes of the Si dangling-bond signal intensity were observed when the deposition started and stopped, which has suggested the existence of a subsurface region with higher spin density than that in the bulk region.

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.

Properties and Local Structure of Plasma-Deposited Amorphous Silicon-Carbon Alloys

1986 ◽  
Vol 70 ◽  
Author(s):  
W. C. Mohr ◽  
C. C. Tsai ◽  
R. A. Street
Keyword(s):  
Substrate Temperature ◽  
Amorphous Silicon ◽  
Gas Phase ◽  
Vacuum Annealing ◽  
Dangling Bond ◽  
Bond Density ◽  
Silicon Carbon ◽  
Back Bonding ◽  
Hydrogenated Amorphous ◽  
Gas Ratio

ABSTRACTHydrogenated amorphous silicon-carbon alloy films were plasma-deposited from metnane and silane, varying gas ratio, R.F. power and substrate temperature. Carbon addition increases the optical gap, but also raises the dangling bond density while decreasing conductivity. Low C alloys can be gas-phase doped both p and n type. In the IR spectra the various Si-C stretching modes observed between 650 and 780 cm-1 are explained by back bonding variations. A tentative method of assigning this shift to back bonding of C to the Si is given. A distribution of modes is observed for all alloys, with each mode appearing even at 2% C. The distribution is sensitive to substrate temperature, but is stable after vacuum annealing to 400°C.

Surface Microchemical Reactions during Hydrogenated Silicon Growth Studied by In-situ ESR Technique

2000 ◽  
Vol 609 ◽  
Author(s):  
Satoshi Yamasaki
Keyword(s):  
Crystalline Silicon ◽  
High Vacuum ◽  
Chemical Vapor ◽  
Ultra High Vacuum ◽  
Dynamic Surface ◽  
Hydrogenated Silicon ◽  
Silicon Growth ◽  
Hydrogenated Amorphous

ABSTRACTThe in-situ ESR technique is applied to a plasma-enhanced chemical vapor deposition (PECVD) system in order to investigate the surface microchemical reactions during the growth of hydrogenated amorphous silicon (a-Si:H) and plasma treatments of H2 and Ar gases on a- Si:H. The growth model of a-Si:H and the role of H atoms on a-Si:H films are discussed using the experimental results. The recent results on the dynamic surface reactions of crystalline silicon with oxygen molecules in an ultra-high-vacuum ESR system are introduced.

Dopant Incorporation and Doping Efficiency in a-Si:H and a-Ge:H

1986 ◽  
Vol 70 ◽  
Author(s):  
Martin Stutzmann
Keyword(s):  
Gas Phase ◽  
Hydrogenated Amorphous Silicon ◽  
Square Root ◽  
Dangling Bond ◽  
Band Tail ◽  
Gas Concentration ◽  
Dopant Incorporation ◽  
Solid Film ◽  
Silicon And Germanium ◽  
Hydrogenated Amorphous

ABSTRACTDoping of hydrogenated amorphous silicon and germanium with boron, phosphorus, and arsenic is investigated. The incorporation of the dopants from the gas phase into the solid film is found to differ strongly for the various dopant-host systems. The doping efficiency is calculated from measurements of the density of dangling bond defects and of shallow band-tail states as a function of the doping level. A common square root dependence of the efficiency on dopant gas concentration is obtained.

scholarly journals In Situ Observation of Electron-Beam-Induced Formation of Nano-Structures in PbTe

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 163
Author(s):  
Iryna Zelenina ◽  
Igor Veremchuk ◽  
Yuri Grin ◽  
Paul Simon
Keyword(s):  
Electron Beam ◽  
Gas Phase ◽  
Threshold Current ◽  
Threshold Current Density ◽  
Atomic Scale ◽  
In Situ Observation ◽  
Nano Structures ◽  
Transmission Electron ◽  
Initial Crystal

Nano-scaled thermoelectric materials attract significant interest due to their improved physical properties as compared to bulk materials. Well-shaped nanoparticles such as nano-bars and nano-cubes were observed in the known thermoelectric material PbTe. Their extended two-dimensional nano-layer arrangements form directly in situ through electron-beam treatment in the transmission electron microscope. The experiments show the atomistic depletion mechanism of the initial crystal and the recrystallization of PbTe nanoparticles out of the microparticles due to the local atomic-scale transport via the gas phase beyond a threshold current density of the beam.

scholarly journals Dry Etching Performance and Gas-Phase Parameters of C6F12O + Ar Plasma in Comparison with CF4 + Ar

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1595
Author(s):  
Nomin Lim ◽  
Yeon Sik Choi ◽  
Alexander Efremov ◽  
Kwang-Ho Kwon
Keyword(s):  
Gas Phase ◽  
Photoelectron Spectroscopy ◽  
Reactive Ion Etching ◽  
Research Work ◽  
Optical Emission ◽  
Plasma Parameters ◽  
Ion Etching ◽  
Ar Plasma ◽  
Ar Gas ◽  
Etching Selectivity

This research work deals with the comparative study of C6F12O + Ar and CF4 + Ar gas chemistries in respect to Si and SiO2 reactive-ion etching processes in a low power regime. Despite uncertain applicability of C6F12O as the fluorine-containing etchant gas, it is interesting because of the liquid (at room temperature) nature and weaker environmental impact (lower global warming potential). The combination of several experimental techniques (double Langmuir probe, optical emission spectroscopy, X-ray photoelectron spectroscopy) allowed one (a) to compare performances of given gas systems in respect to the reactive-ion etching of Si and SiO2; and (b) to associate the features of corresponding etching kinetics with those for gas-phase plasma parameters. It was found that both gas systems exhibit (a) similar changes in ion energy flux and F atom flux with variations on input RF power and gas pressure; (b) quite close polymerization abilities; and (c) identical behaviors of Si and SiO2 etching rates, as determined by the neutral-flux-limited regime of ion-assisted chemical reaction. Principal features of C6F12O + Ar plasma are only lower absolute etching rates (mainly due to the lower density and flux of F atoms) as well as some limitations in SiO2/Si etching selectivity.

scholarly journals An Atmospheric Origin for HCN-Derived Polymers on Titan

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 965
Author(s):  
Zoé Perrin ◽  
Nathalie Carrasco ◽  
Audrey Chatain ◽  
Lora Jovanovic ◽  
Ludovic Vettier ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Gas Phase ◽  
Formation Process ◽  
Upper Atmosphere ◽  
Gas Mixture ◽  
Space Probe ◽  
Atmospheric Haze ◽  
Formation And Evolution ◽  
Haze Formation

Titan’s haze is strongly suspected to be an HCN-derived polymer, but despite the first in situ measurements by the ESA-Huygens space probe, its chemical composition and formation process remain largely unknown. To investigate this question, we simulated the atmospheric haze formation process, experimentally. We synthesized analogues of Titan’s haze, named Titan tholins, in an irradiated N2–CH4 gas mixture, mimicking Titan’s upper atmosphere chemistry. HCN was monitored in situ in the gas phase simultaneously with the formation and evolution of the haze particles. We show that HCN is produced as long as the particles are absent, and is then progressively consumed when the particles appear and grow. This work highlights HCN as an effective precursor of Titan’s haze and confirms the HCN-derived polymer nature of the haze.

In Situ Optical Analysis of the Gas Phase during the Deposition of Silicon Carbide from Methyltrichlorosilane

1996 ◽  
Vol 143 (5) ◽  
pp. 1654-1661 ◽  
Author(s):  
M. Ganz ◽  
N. Dorval ◽  
M. Lefebvre ◽  
M. Péalat ◽  
F. Loumagne ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Gas Phase ◽  
Optical Analysis
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