Influence of Plasma Chemistry on the Properties of Amorphous (Si,Ge) Alloy Devices

1998 ◽  
Vol 507 ◽  
Author(s):  
Vikram L. Dalal ◽  
Tim Maxson ◽  
Sohail Haroon
Keyword(s):  
Momentum Transfer ◽  
Plasma Deposition ◽  
Hydrogen Plasma ◽  
Plasma Chemistry ◽  
Ion Bombardment ◽  
Film Properties ◽  
Efficient Energy ◽  
Ecr Plasma ◽  
Amorphous Si ◽  
Energy And Momentum

ABSTRACTWe report on the growth and properties of a-(Si,Ge):H films and p-i-n solar cell devices prepared using a remote, low pressure ECR plasma deposition technique. The films and devices were prepared using either He or H2 as the diluent gas. The plasma conditions were controlled so as to induce significant ion bombardment during growth. We find that there is a dramatic influence of plasma chemistry on the growth and properties of a-(Si,Ge):H films and devices. In particular, with hydrogen as the diluent gas, changing the pressure in the reactor dramatically changes both the Germanium incorporation in the film, and the electronic properties. Lower pressures lead to less Ge being incorporated, and higher mobility-lifetime product for holes for a given Tauc gap, as well as better p-i-n devices. In contrast, changing the pressure when He is the diluent gas does not produce such large changes. We speculate that the changes in device and film properties are due to the influence of ion bombardment on growth chemistry, and that both efficient energy and momentum transfer to the growing surface are necessary to achieve the best devices. The differences between He and hydrogen may simply be due to the fact that He plasma is much more energetic than a comparable hydrogen plasma, and there is more efficient momentum transfer when He is used as compared to when hydrogen is used. We have also produced very good single junction a-(Si,Ge) devices using the ECR technique.

tudies on Titanium Nitride Coatings - Effect of Ion Bombardment

2000 ◽  
Vol 647 ◽  
Author(s):  
K. Deenamma Vargheese ◽  
G. Mohan Rao
Keyword(s):  
Titanium Nitride ◽  
Electron Cyclotron Resonance ◽  
Film Growth ◽  
Morphological Changes ◽  
Ion Bombardment ◽  
Ion Flux ◽  
Film Properties ◽  
Ion Energy ◽  
Ecr Plasma ◽  
Plasma Sputtering

AbstractIon bombardment during thin film growth is known to cause structural and morphological changes in the deposited films and thus affecting the film properties. These effects can be due to the variation in the bombarding ion flux or their energy. We have deposited titanium nitride films by two distinctly different methods, viz. Electron Cyclotron Resonance (ECR) plasma sputtering and bias assisted reactive magnetron sputtering. The former represents low energy (typically less than 30 eV) but high density plasma (1011cm−3), whereas, in the latter case the ion energy is controlled by varying the bias to the substrate (typically a few hundred volts) but the ion flux is low (109cm−3). The deposited titanium nitride films are characterized for their structure, grain size, surface roughness and electrical resistivity.

ECR Plasma Deposition of Dielectrics for Optoelectronic Applications

1989 ◽  
Vol 165 ◽  
Author(s):  
Steven Dzioba
Keyword(s):  
Electron Cyclotron Resonance ◽  
Plasma Deposition ◽  
Plasma Source ◽  
Optoelectronic Device ◽  
Dielectric Films ◽  
Film Properties ◽  
Ecr Plasma ◽  
Device Applications ◽  
Inp Substrates

A UHV electron cyclotron resonance (ECR) plasma source has been used to deposit SiNx, SiOxNy and amorphous Si thin films on InP substrates for optoelectronic device applications. High quality dielectric films can be deposited at temperatures significantly lower than conventional techniques, namely less than 110°C. Selected applications pertinent to optoelectronic devices are used to establish the role of ion/electron fluxes in thin film properties.

The Role of Ions for the Deposition of Hydrocarbon Films, investigated by In-Situ Ellipsometry

1995 ◽  
Vol 388 ◽  
Author(s):  
A. Von Keudell
Keyword(s):  
Growth Rate ◽  
Film Surface ◽  
Ion Bombardment ◽  
Floating Potential ◽  
Film Properties ◽  
Ecr Plasma ◽  
Hydrocarbon Films ◽  
Self Bias

AbstractThe growth mechanisms for the deposition of hydrocarbon films (C:H-films) from a methane electron cyclotron resonance (ECR) plasma are investigated by means of in-situ ellipsometry. Ion bombardment during plasma-enhanced chemical vapor deposition of hydrocarbon films mainly governs the properties of the films and the total growth rate. the role of ions for the growth rate and the film properties is discussed in this paper. Films were deposited with varying RF-bias, resulting in a DC self-bias ranging from floating potential up to 100 V. the ion-induced modification of the film properties was investigated by a new technique using a double layer consisting of a polymer-like film with low optical absorption and a hard carbon film with high absorption on top. the interface between these layers was analysed after deposition by a layer-by-layer etching in an oxygen plasma at floating potential. From these data it is possible to determine with high accuracy the range of the ion-induced modification of the optical properties in the underlying polymer-like film. the thickness of this modified layer ranges from 6 Å at 30 V self-bias to 40 Å at 100 V self-bias, which is consistent with the range of hydrogen ions in polymerlike films as calculated by the computer code TRIM.SP.Based on the presented results, the growth of C:H-films and the resulting film properties can be modelled by the growth at activated sites at the film surface. these activated sites are represented by dangling bonds, induced by the ion bombardment. they also show up in the ellipsometric results during the deposition of C:H-films by a change of the optical response of the film surface.

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.

Growth Mechanism and Film Properties in Pulsed Laser-Plasma Deposition

1991 ◽  
Vol 236 ◽  
Author(s):  
S. Metev ◽  
K. Meteva
Keyword(s):  
Laser Plasma ◽  
Growth Process ◽  
Plasma Deposition ◽  
Pulsed Laser ◽  
Deposition Process ◽  
Experimental Investigations ◽  
Direct Relation ◽  
Film Properties ◽  
Experimental Conditions ◽  
Laser Flux

AbstractIn the paper the results of a theoretical investigation of the growth process of laser-plasma deposited thin films are discussed. A kinetic approach has been used to establish direct relation between experimental conditions (laser flux density, substrate temperature) and film properties (thickness, structure). The results of some experimental investigations of the deposition process are presented confirming the general conclusions of the developed theoretical model.

On Length Scales for the Radial Rotating Jet Pressure Exchange Mechanism

2008 ◽  
Author(s):  
Muhammad Umar ◽  
Charles A. Garris
Keyword(s):  
Momentum Transfer ◽  
Near Field ◽  
Exchange Process ◽  
Energy Levels ◽  
Mixing Layer ◽  
Complex Flow ◽  
Transfer Energy ◽  
Length Scales ◽  
Pressure Exchange ◽  
Energy And Momentum

The crypto-steady rotating jet pressure exchange ejector is a novel concept in turbomachinery where two fluids, at different energy levels, come in direct contact with each other to transfer energy and momentum between them through non-steady interface pressure forces. The current paper seeks to provide an insight into the complex flow phenomena occurring inside the radial flow pressure exchange ejector. The primary mechanisms controlling the process are pressure exchange and mixing. This paper will seek to discriminate between energy transfer by each respective mechanism. The energy and momentum transfer in the near field is shown to be mainly due to the pressure exchange process, as the mixing layer does not develop substantially in this region. As the radius increases, the mixing layer tends to grow and the energy and momentum transfer is governed by the mixing process. As a consequence, the length scales of the pressure exchange zone are small, thus making the pressure exchange ejector more compact in size. The paper will delineate between the two length scales. If this new concept is shown to be viable for gas compression at sufficiently high pressure ratios, then, in refrigeration applications, it would enable environmentally benign refrigerants to replace the harmful chlorofluorocarbons (CFC) and reduce the effluence of greenhouse gases. Applications in many other areas, where conventional ejectors are currently used, are also possible.

Nanocrystalline Germanium and Germanium Carbide Films and Devices

2005 ◽  
Vol 862 ◽  
Author(s):  
Xuejun Niu ◽  
Jeremy Booher ◽  
Vikram L. Dalal
Keyword(s):  
Grain Size ◽  
Plasma Deposition ◽  
Open Circuit ◽  
Image Sensors ◽  
High Hydrogen ◽  
Strong Function ◽  
Germanium Carbide ◽  
Ecr Plasma ◽  
Hydrogen Dilution ◽  
Steel Substrates

AbstractNanocrystalline Ge and its alloys with C are potentially useful materials for solar cells, thin film transistors and image sensors. In this paper, we discuss the growth and properties of these materials using remote, low pressure ECR plasma deposition. The materials and devices were grown from mixtures of germane, methane and hydrogen. It was found that high hydrogen dilutions (>40:1) were needed to crystallize the films. Studies of x-ray spectra revealed that the grains were primarily <220> oriented. The grain size was a strong function of hydrogen dilution and growth temperature. Higher growth temperatures resulted in larger grain size. High hydrogen dilution tended to reduce grain size. These results can be explained by recognizing that excessive amounts of bonded H can inhibit the growth of <220> grain, which is the thermodynamically favorable direction for grain growth. Grain sizes as large as 80 nm were obtained in nc-Ge. Addition of C reduced the crystallinity. Mobility and carrier concentrations in nc-Ge were measured using Hall effect. Mobility values of ˜5cm2/V-sand carrier concentrations of ˜1x1016/cm3were obtained in larger grains. p+nn+ devices were fabricated on stainless steel substrates and compared with similar devices deposited in nc-Si:H. It was found that the voltage decreased and current increased in nc-Ge devices, in comparison with devices in nc-Si:H. Addition of C to Ge devices increased the open circuit voltage and shifted the quantum efficiency to larger photon energies, as expected.

Microstructural Analysis of Copper Foil Etched and Annealed in ECR Plasma Reactor

2022 ◽  
Vol 1048 ◽  
pp. 121-129
Author(s):  
Samit Karmakar ◽  
Soumik Kumar Kundu ◽  
Aditya Mukherjee ◽  
Sujit Kumar Bandyopadhyay ◽  
Satyaranjan Bhattacharyya ◽  
...  
Keyword(s):  
Copper Foil ◽  
Electron Cyclotron Resonance ◽  
Plasma Reactor ◽  
Hydrogen Plasma ◽  
Microstructural Analysis ◽  
Chemical Vapour ◽  
Working Pressure ◽  
Ecr Plasma ◽  
Average Grain Size ◽  
Xrd Studies

Microstructural analysis of commercially available cold-rolled polycrystalline copper foil, etched and annealed in an in-house developed Electron Cyclotron Resonance (ECR) Plasma Enhanced Chemical Vapour Deposition (PE-CVD) reactor, have been carried out using x-ray diffraction (XRD) studies. The annealing experiments were carried out under a vacuum environment, keeping the working pressure of the reactor at 50×10-3 mbar, for three different time spans of 30 mins, 45 mins and 1 hour at 823 K (550 °C) and 923 K (650 °C) respectively in presence of hydrogen plasma. The XRD studies reveal the significance of annealing time at two different temperatures for the determination of physical and microstructural parameters such as the average grain size and micro-strain in copper lattice by Williamson-Hall (W-H) method.

Sign in / Sign up

Export Citation Format

Share Document