An Approach to High Quality a-Ge:H by VHF Deposition

1993 ◽  
Vol 297 ◽  
Author(s):  
Ralf Zedlitz ◽  
Moritz Heintze ◽  
Gottfried H. Bauer
Keyword(s):  
High Frequency ◽  
Parallel Plate ◽  
Charge Carriers ◽  
Substrate Plane ◽  
Very High Frequency ◽  
High Quality ◽  
Ion Energy ◽  
Preparation Conditions ◽  
Parallel Plate Reactor ◽  
Very High

Amorphous hydrogenated germanium a-Ge:H was deposited by very high frequency glow discharge (VHF-GD) at frequencies between 25 and 220MHz, low pressure (2.5Pa) and high deposition rates (≤4Á /s) on both electrodes of a parallel plate reactor. The films are comparable to material deposited on the powered electrode of a conventional RF-GD. Mobility-lifetime products ηµτ for photogenerated charge carriers around 10-7cm2/V and a Fermi level position at EC-EF≈400meV indicate good opto-electronic properties. The IR spectra show that the samples are free of oxydization and incorporate slightly more voids than the RF material. Measurements of ion energy Ei and flux Фi in the substrate plane show that “hard&” preparation conditions are obtained comparable to the deposition on the powered electrode of an RF-GD.

Diamond synthesis by using very high frequency plasmas in parallel plate electrodes configuration

1997 ◽  
Vol 71 (18) ◽  
pp. 2707-2709 ◽  
Author(s):  
Seiichiro Matsumoto ◽  
Yoshiki Asakura ◽  
Kenji Hirakuri
Keyword(s):  
High Frequency ◽  
Parallel Plate ◽  
Diamond Synthesis ◽  
Very High Frequency ◽  
Very High

Diagnostics of VHF Plasma Deposition

1992 ◽  
Vol 258 ◽  
Author(s):  
J. Kuske ◽  
U. Stephan ◽  
K. Schade ◽  
W. Fuhs
Keyword(s):  
High Frequency ◽  
Plasma Deposition ◽  
Deposition Process ◽  
Electrical Network ◽  
Very High Frequency ◽  
Electrical Connection ◽  
Reactor Construction ◽  
Parallel Plate Reactor ◽  
Very High ◽  
Deposition Conditions

ABSTRACTThe use of Very High Frequency (VHF) glow discharge for the deposition of amorphous silicon films is one approach to influencing the deposition conditions.For the experiments a capacitatively-coupled parallel plate reactor with two aluminium electrodes of 125 mm in diameter is used. The VHF is generated by means of an all-solid state amplifier which has a frequency response ranging from 250 kHz to 150 MHz. Experiments with an nitrogen discharge within the range from 5 to 150 MHz are an principle in agreement with the results in the literature. The results show, that the frequency dependence of the discharge strongly depends on the design and the external electrical connection of the VHF-reactor. In the examined range of frequency resonances appear, which are probably responsible for the maximum of the deposition rate. These resonances are not essentially resultant from changes in the physics of the discharge but a result of the reactor construction and the external electrical connection. Possibilities which influence this frequencies of resonance will be discussed.Results for an electrical network model will be discussed in the comparison with different reactors and the optimization of the behaviour of the deposition process.

Effect of gas pressure on ion energy at substrate side of Ag target radio-frequency and very-high-frequency magnetron sputtering discharge

2021 ◽  
Author(s):  
Weichen Ni ◽  
Chao Ye ◽  
Yiqing Yu ◽  
Xiangying Wang
Keyword(s):  
Magnetron Sputtering ◽  
Radio Frequency ◽  
High Frequency ◽  
Excitation Frequency ◽  
Gas Pressure ◽  
Very High Frequency ◽  
Magnetron Discharge ◽  
Ion Energy ◽  
Substrate Side ◽  
Very High

Abstract The effect of gas pressure on ion energy distribution at the substrate side of Ag target radio-frequency (RF) and very-high-frequency (VHF) magnetron sputtering discharge was investigated. At the lower pressure, the evolution of maximum ion energy (E) with the discharge voltage (V) varied with the excitation frequency, due to the joint contribution of the ion generation in the bulk plasma and the ion movement across the sheath related to the ion transit sheath time τi and RF period RF. At the higher pressure, the evolution of E-V relationships do not vary with the excitation frequency, due to the balance between the energy lost through collisions and the energy gained by acceleration in the electric field. Therefore, for the RF and VHF magnetron discharge, the lower gas pressure can have a clear influence on the E-V relationship.

Experimental Investigation of very High Frequency Slot Antenna on M-60A-1 Tank

1977 ◽  
Author(s):  
D. V. Campbell ◽  
William Kennebeck ◽  
A. Zanella ◽  
Paul Sexton
Keyword(s):  
Experimental Investigation ◽  
High Frequency ◽  
Slot Antenna ◽  
Very High Frequency ◽  
Very High

A collision feedback based multiple access control protocol for very high frequency data exchange system in E-navigation

2021 ◽  
pp. 1-16
Author(s):  
Xu Hu ◽  
Bin Lin ◽  
Ping Wang ◽  
Hongguang Lyu ◽  
Tie-Shan Li
Keyword(s):  
Access Control ◽  
High Frequency ◽  
Multiple Access ◽  
Data Exchange ◽  
High Frequency Data ◽  
Frequency Data ◽  
Exchange System ◽  
Very High Frequency ◽  
Time Division ◽  
Very High

Abstract The very high frequency data exchange system (VDES) is promising in promoting electronic navigation (E-navigation) and improving navigation safety. The multiple access control (MAC) protocol is crucial to the transmission performance of VDES. The self-organising time division multiple access (SOTDMA) protocol, as the only access mode given by current recommendations, leads to a high rate of transmission collisions in the traditional automatic identification system (AIS), especially with heavy traffic loads. This paper proposes a novel feedback based time division multiple access (FBTDMA) protocol to address the problems caused by SOTDMA, such that collision of transmissions can be avoided in information transmission among vessels. Simulation results demonstrate that the proposed FBTDMA outperforms the traditional SOTDMA in terms of channel utilisation and throughput, and significantly reduces the transmission collision rate. The study is expected to provide insights into VDES standardisation and E-navigation modernisation.

Sign in / Sign up

Export Citation Format

Share Document