Thin amorphous films of LiPON solid electrolyte were prepared by anodic evaporation of lithium orthophosphate Li3PO4 in an arc discharge with a self-heating hollow cathode at a nitrogen pressure of 1 Pa. Distribution of the arc current between two electrodes having an anode potential provided independent control of the evaporation rate of Li3PO4 and the density of nitrogen plasma. Stabilization of the evaporation rate was achieved using a crucible with multi-aperture cover having floating potential. The existence of a threshold value of discharge current (40 A) has been established, which, upon reaching ionic conductivity over 10−8 S/cm, appears in the films. Probe diagnostics of discharge plasma were carried out. It has been shown that heating the films during deposition by plasma radiation to a temperature of 200 °C is not an impediment to achieving high ionic conductivity of the films. Dense uniform films of LiPON thickness 1 mm with ionic conductivity up to 1 × 10−6 S/cm at a deposition rate of 4 nm/min are obtained.
The monitoring of the degree of oxygen dissociation in the discharge plasma is critical for various plasma applications associated with the etching and oxidation of surfaces or the reactive deposition of oxide coatings. The use of existing measurement techniques is limited owing to their complexity, significant error rate, or application conditions. This study deals with the development of a catalytic probe method for measuring the degree of oxygen dissociation in dense arc discharge plasma. A method for measuring and processing the experimental results is presented, which allows the determination of the thermal contribution of the heterogeneous recombination of oxygen atoms at a high total heating power of the catalytic probe by particle streams and plasma radiation. The atomic oxygen concentration was measured in low-pressure arc plasma with a self-heating hollow cathode in an Ar/O2 mixture with changes in the discharge current and oxygen partial pressure over a wide range of 30–70 A and 0.2–0.6 Pa, respectively. It has been demonstrated that the maximum degree of oxygen dissociation (up to 25% of the O2 content) is achieved at the maximum discharge current and is practically independent of the oxygen flow, whereas the highest concentration of atomic oxygen is achieved when the maximum current and O2 flow values are combined. This conclusion is important for technologies based on plasma-chemical processes in high-current discharges.
The results of a study on O 2 dissociation conditions in the near-anode area of forcibly compressed low-pressure arc discharge are presented. A combined mode of discharge operation was applied to increase the O 2 dissociation degree. In this mode, high-current pulses (up to 160 A) of short duration (100 μs) were imposed on a direct current discharge (up to 70 A). Probe measurements showed that a higher atomic oxygen concentration is caused by increasing not only the electron current, but also the voltage drop in the anode part of the discharge in the pulsed phase. A necessary condition for achieving high average values of O 2 dissociation degree at high pulse ratio is the increased lifetime of oxygen atoms in the volume. This condition is fulfilled in a gas-discharge system with metal walls used for the deposition of oxide coatings through formation on the walls of amorphous oxide films, which have a low atomic oxygen recombination coefficient. An O 2 dissociation degree of ∼0.4 in a low-pressure arc (less than 1 Pa) in Ar/O 2 mixture was obtained by optimizing the parameters of the arc operation mode and the condition of the wall surface of the gas-discharge system.
α-Al2O3 coatings have been deposited by evaporation of Al in an anodic arc with a growth rate of ~ 5 μm·h−1 at 640°C under the conditions of low ionization of the Al vapors and an increased concentration of atomic oxygen, which has been achieved by the use of a hollow anode.Intensive (current density up to 15 mA·cm−2) low-energy (50 eV) ion bombardment has provided deposition of adhesive single-phase nanocrystalline (50–150 nm) α-Al2O3 coatings with a thickness of up to 10 μm with low intrinsic stresses (1.5 GPa) and low microstrains of the crystal lattice (less than 0.1%). The composition of the discharge plasma has been determined using the optical spectroscopy method. The effect of the O2 flow and the hollow anode current on the growth rate of the alumina coatings has been investigated and it has been shown that the increasing degree of O2 dissociation promotes an increase in the growth rate of coatings.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.