Experimental Evidence for the Dominance of vuv Photons in Remote Hydrogen Plasma Treatments

1998 ◽  
Vol 544 ◽  
Author(s):  
R. Wilken ◽  
A. Hollander ◽  
J. Behnisch
Keyword(s):  
Vacuum Ultraviolet ◽  
Microwave Plasma ◽  
Hydrogen Plasma ◽  
Plasma Source ◽  
Power Input ◽  
Photon Flux ◽  
Fluorescence Measurements ◽  
Plasma Treatments ◽  
Uv Photons

AbstractThe flux of vacuum ultraviolet (VUV) and ultraviolet (UV) photons from a hydrogen plasma was detected by fluorescence measurements of sodium salicylate sheets with and without a MgF2 window. In order to expose the samples to the same photon flux in all experiments, the power input to the microwave plasma source was adjusted. Polyethylene (PE), polypropylene (PP), and polystyrene (PS) were treated with VUV radiation or with a remote hydrogen plasma. The mass loss and the CH-absorption loss were recorded by in situ quartz crystal micro balance and by in situ IR reflection absorption spectroscopy, respectively. The VUV irradiation and plasma treatment caused similar effects in the case of PE, PP showed an increased polymer ablation in plasma treatments, and for PS a negligible loss in mass and CH absorption was detected in plasma and VUV treatments.

Passivation of III-V Semiconductor Surfaces Using Light Assisted Integrated Processes

1994 ◽  
Vol 342 ◽  
Author(s):  
Olivier Dulac ◽  
Yves I. Nissim
Keyword(s):  
Field Effect ◽  
Microwave Plasma ◽  
Hydrogen Plasma ◽  
Surface Cleaning ◽  
Film Deposition ◽  
Gaas Surface ◽  
Nitride Film ◽  
Semiconductor Surfaces ◽  
Silicon Nitride Film

ABSTRACTPassivation of III-V semiconductor surfaces and especially the GaAs surface has been studied for over two decades without significant breakthrough. However, III-V device performances are still often limited by surface properties. In particular field effect behaviour in GaAs has been impossible to obtain due to the Fermi level pinning at the surface of this material. This paper presents an integrated sequence of low thermal budget processes to provide contamination control at the GaAs surface leading to very promising field effect on GaAs.In-situ surface cleaning using a Distributed Electron Cyclotron Resonance Microwave plasma (DECR MMP) has been integrated with a thin dielectric film deposition facility using light assisted CVD technics. Photoluminescence results carried out on GaAs surfaces have demonstrated that exposure to a hydrogen plasma induces lower recombination rates on these surfaces. Bulk diffusion of hydrogen during this process can be controlled and eliminated using an integrated Rapid Thermal Annealing (RTA). Finally, in-situ encapsulation by a dielectric allows one to stabilize the electronic properties of the surface for passivation applications. A silicon nitride film deposited by a direct UV photolysis deposition process has been developed for this study and is presented here.

In-Situ Surface Cleaning of Ge(111) and Si(100) for Epitaxial Growth of Ge AT 300°C Using Remote Plasma Enhanced Chemical Vapor Deposition

1987 ◽  
Vol 102 ◽  
Author(s):  
S. V. Hattangady ◽  
R. A. Rudder ◽  
G. G. Fountain ◽  
D. J. Vitkavage ◽  
R. J. Markunas
Keyword(s):  
Vapor Deposition ◽  
Hydrogen Plasma ◽  
Chemical Vapor ◽  
High Energy ◽  
Surface Cleaning ◽  
High Energy Electron ◽  
New Approach ◽  
Wet Chemistry ◽  
Plasma Treatments

We have demonstrated low temperature (300°C) Ge epitaxy on Ge(111) and on Si(100) substrates. Critical to this epitaxy has been the use of wet chemistry to produce controlled, thin oxides on the substrates prior to loading into the reactor and an in-situ 300°C hydrogen plasma treatment to remove those oxides from the semiconductor surfaces. Reflection high energy electron diffraction shows the plasma treatments to be effective in producing clean, well-ordered surfaces. This represents a new approach for in-situ cleaning of Ge(111) and Si(100) surfaces.

Characterization of a slot antenna microwave plasma source for hydrogen plasma cleaning

1995 ◽  
Vol 13 (4) ◽  
pp. 2074-2085 ◽  
Author(s):  
D. Korzec ◽  
F. Werner ◽  
A. Brockhaus ◽  
J. Engemann ◽  
T. P. Schneider ◽  
...  
Keyword(s):  
Microwave Plasma ◽  
Hydrogen Plasma ◽  
Plasma Source ◽  
Slot Antenna ◽  
Plasma Cleaning

Improvement in the Sensitivity of the Response of Diamond Thin Films to X-Ray

2007 ◽  
Vol 336-338 ◽  
pp. 1718-1721 ◽  
Author(s):  
Xiao Ming Liao ◽  
Jun Guo Ran ◽  
Li Gou ◽  
Jin Zhang ◽  
Bao Hui Su ◽  
...  
Keyword(s):  
Microwave Plasma ◽  
Hydrogen Plasma ◽  
Diamond Films ◽  
Chemical Vapor ◽  
High Sensitivity ◽  
Post Treatment ◽  
X Ray ◽  
Microwave Plasma Cvd ◽  
Higher Sensitivity

Due to some inferior performance of Chemical Vapor Deposition (CVD) diamond dosimeters, their applications are somewhat limited. The quality of diamond films was improved using Microwave Plasma CVD (MWPCVD) by the modified processes such as cyclic deposition and in-situ plasma post-treatment. The simple radiation dosimeters were fabricated in a sandwich configuration. Influence of purity and orientation of the diamond films on the sensitivity of the dosimeters was studied. The results indicate that the radiation dosimeters have high sensitivity to X-ray and the response of the devices is linear with the X-ray flux. The higher the purity of films is, the higher the resistivity and sensitivity are. The dosimeter based on [100] film has higher sensitivity than that based on [111] film. The dosimeter based on films prepared by cyclic deposition has higher sensitivity than that based on films prepared by the conventional deposition. The characterization of the response to X-ray also shows that in-situ oxygen plasma post-treatment leads to the higher sensitivity of dosimeters compared with in-situ nitrogen, hydrogen plasma post-treatments.

In Situ Fhir Spectroscopic Detection of Adsorbed Species on Sapphire Substrates in a Diamond ECR-Pacvd System

1997 ◽  
Vol 502 ◽  
Author(s):  
F. Shahedipour ◽  
S. Zhu ◽  
H. W. White
Keyword(s):  
Electron Cyclotron Resonance ◽  
Microwave Plasma ◽  
Hydrogen Plasma ◽  
Chemical Vapor ◽  
Diamond Deposition ◽  
Diamond Nucleation ◽  
Sapphire Substrates ◽  
Film Synthesis ◽  
Deposition Conditions

ABSTRACTIn situ Fourier Transform Infrared Reflection Absorption Spectroscopy (FTIRRAS) has been used to study the adsorbed plasma species on sapphire substrate throughout the nucleation and deposition stages under diamond deposition conditions. The focus of this work has been on one of the most fundamental questions in the area of diamond film synthesis that concerns the gas species (precursors) responsible for diamond nucleation and growth especially on foreign substrates. It is experimentally shown here that the most probable precursor for diamond nucleation in methane-hydrogen plasma are methyl radicals.Diamond deposition on randomly oriented sapphire substrates has been successfully achieved under low pressure- low temperature deposition conditions using an electron cyclotron resonance microwave plasma assisted chemical vapor deposition (ECR-PACVD) system. The deposited thin films were characterized by Raman spectroscopy, and scanning electron microscopy.

In situ growth rate measurement and nucleation enhancement for microwave plasma CVD of diamond

1992 ◽  
Vol 7 (2) ◽  
pp. 257-260 ◽  
Author(s):  
B.R. Stoner ◽  
B.E. Williams ◽  
S.D. Wolter ◽  
K. Nishimura ◽  
J.T. Glass
Keyword(s):  
Growth Rate ◽  
Microwave Plasma ◽  
Hydrogen Plasma ◽  
Diamond Particle ◽  
Chemical Vapor ◽  
Processing Parameters ◽  
Ex Situ ◽  
Particle Nucleation ◽  
Cross Sectional

Laser reflection interferometry (LRI) has been shown to be a useful in situ technique for measuring growth rate of diamond during microwave plasma chemical vapor deposition (MPCVD). Current alternatives to LRI usually involve ex situ analysis such as cross-sectional SEM or profilometry. The ability to measure the growth rate in ‘real-time’ has allowed the variation of processing parameters during a single deposition and thus the extraction of much more information in a fraction of the time. In situ monitoring of growth processes also makes it possible to perform closed loop process control with better reproducibility and quality control. Unfortunately, LRI requires a relatively smooth surface to avoid surface scattering and the commensurate drop in reflected intensity. This problem was remedied by greatly enhancing the diamond particle nucleation via the deposition of an intermediate carbon layer using substrate biasing. When an unscratched silicon wafer is pretreated by biasing negatively relative to ground while in a methane-hydrogen plasma, nucleation densities much higher than those achieved on scratched silicon wafers are obtained. The enhanced nucleation allows a complete film composed of small grains to form in a relatively short time, resulting in a much smoother surface than is obtained from a film grown at lower nucleation densities.

scholarly journals A prospective microwave plasma source for in situ spaceflight applications

2020 ◽  
Vol 35 (11) ◽  
pp. 2740-2747
Author(s):  
B. J. Farcy ◽  
R. D. Arevalo ◽  
M. Taghioskoui ◽  
W. F. McDonough ◽  
M. Benna ◽  
...  
Keyword(s):  
Low Power ◽  
Organic Molecules ◽  
Microwave Plasma ◽  
Plasma Source ◽  
Reduced Pressure ◽  
Planetary Environments ◽  
Refractory Elements

We report full ionization of organic molecules or refractory elements with a low power and reduced-pressure microwave plasma source that can be applied to any specific analyzer for deployment in remote terrestrial and planetary environments.

Material Structure of Microcrystalline Silicon Deposited with an Expanding Thermal Plasma

2003 ◽  
Vol 762 ◽  
Author(s):  
C. Smit ◽  
D.L. Williamson ◽  
M.C.M. van de Sanden ◽  
R.A.C.M.M. van Swaaij
Keyword(s):  
Thermal Plasma ◽  
Hydrogen Plasma ◽  
Plasma Chemistry ◽  
Plasma Source ◽  
Growth Direction ◽  
Interaction Time ◽  
Material Structure ◽  
Average Particle ◽  
Microcrystalline Silicon ◽  
X Ray

AbstractExpanding thermal plasma CVD (ETP CVD) has been used to deposit thin microcrystalline silicon films. In this study we varied the position at which the silane is injected in the expanding hydrogen plasma: relatively far from the substrate and close to the plasma source, giving a long interaction time of the plasma with the silane, and close to the substrate, resulting in a short interaction time. The material structure is studied extensively. The crystalline fractions as obtained from Raman spectroscopy as well as from X-ray diffraction (XRD) vary from 0 to 67%. The average particle sizes vary from 6 to 17 nm as estimated from the (111) XRD peak using the Scherrer formula. Small angle X-ray scattering (SAXS) and flotation density measurements indicate void volume fractions of about 4 to 6%. When the samples are tilted the SAXS signal is lower than for the untilted case, indicating elongated objects parallel to the growth direction in the films. We show that the material properties are influenced by the position of silane injection in the reactor, indicating a change in the plasma chemistry.

Long-pulse plasma source for SMOLA helical mirror

2021 ◽  
Vol 87 (2) ◽  
Author(s):  
Ivan A. Ivanov ◽  
V. O. Ustyuzhanin ◽  
A. V. Sudnikov ◽  
A. Inzhevatkina
Keyword(s):  
Magnetic Field ◽  
Gas Flow ◽  
Supply Voltage ◽  
Hydrogen Plasma ◽  
Plasma Source ◽  
Lanthanum Hexaboride ◽  
Plasma Stream ◽  
Plasma Parameters ◽  
Plasma Properties ◽  
Plasma Gun

A plasma gun for forming a plasma stream in the open magnetic mirror trap with additional helicoidal field SMOLA is described. The plasma gun is an axisymmetric system with a planar circular hot cathode based on lanthanum hexaboride and a hollow copper anode. The two planar coils are located around the plasma source and create a magnetic field of up to 200 mT. The magnetic field forms the magnetron configuration of the discharge and provides a radial electric insulation. The source typically operates with a discharge current of up to 350 A in hydrogen. Plasma parameters in the SMOLA device are Ti ~ 5 eV, Te ~ 5–40 eV and ni ~ (0.1–1)  × 1019 m−3. Helium plasma can also be created. The plasma properties depend on the whole group of initial technical parameters: the cathode temperature, the feeding gas flow, the anode-cathode supply voltage and the magnitude of the cathode magnetic insulation.

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