Numerical Analysis of the Interactions between Plasma Jet and Powder Particles in PS-PVD Conditions

Plasma spray-physical vapor deposition (PS-PVD) refers to a very low-pressure (~100 Pa) deposition process in which a powder is injected in a high-enthalpy plasma jet, and mostly vaporized and recondensed onto a substrate to form a coating with a specific microstructure (e.g., columnar). A key issue is the selection of the powder particle size that could be evaporated under specific spray conditions. Powder evaporation takes place, first, in the plasma torch between the injection location and nozzle exit and, then, in the deposition chamber from the nozzle exit to the substrate location. This work aims to calculate the size of the particles that can be evaporated in both stages of the process. It deals with an yttria-stabilized zirconia powder and two commercial plasma torches operated at different arc powers with gas mixtures of argon and helium or argon and hydrogen. First, it used computational fluid dynamics simulations to calculate the velocity and temperature fields of the plasma jets under very low-pressure plasma conditions. Then, it estimated the evaporation of the particles injected in both plasma jets assuming an isothermal evaporation process coupled with momentum and heat transfer plasma-particle models in a rarefied plasma. The calculations showed that, for different powers of the Ar–H2 and the Ar–He operating conditions of this study, the heat flux from the plasma jet to particles inside the torch is much higher than that transferred in the deposition chamber while the specific enthalpy transferred to particles is comparable. The argon-helium mixture is more efficient than the argon-hydrogen mixture to evaporate the particles. Particles less than 2 μm in diameter could be fully evaporated in the Ar–He plasma jet while they should be less than 1 µm in diameter in the Ar–H2 plasma jet.

In0.5Ga0.5N Layers by Atomic Layer Deposition

<p><b>We present an ALD approach to metastable In_1‑xGa_xN with 0.1 < x < 0.5 based on co-sublimed solid In- and Ga-precursors that were co-sublimed into the deposition chamber in one pulse. A near In_0.5Ga_0.5N film with a bandgap of 1.94 eV was achieved on Si (100) substrate. Epitaxial In_1‑xGa_xN (0002) was successfully grown directly on 4H-SiC (0001). </b></p>

In0.5Ga0.5N Layers by Atomic Layer Deposition

<p><b>We present an ALD approach to metastable In_1‑xGa_xN with 0.1 < x < 0.5 based on co-sublimed solid In- and Ga-precursors that were co-sublimed into the deposition chamber in one pulse. A near In_0.5Ga_0.5N film with a bandgap of 1.94 eV was achieved on Si (100) substrate. Epitaxial In_1‑xGa_xN (0002) was successfully grown directly on 4H-SiC (0001). </b></p>

Study on Uniform Deposition on 300 mm Silicon Wafer with Sub-100 nm Sized Particles for Cleaning Application

A study for uniform deposition on whole area of wafer was conducted to help check the uniformity of cleaning technology between wafer center to edge. A new method of particle deposition was devised different from the conventional studies using the center nozzle and electric field. Our deposition chamber features wafer rotating method and deposition by the principle of convection and diffusion. In this study, we focused on the effect of wafer rotation speed and rotation number to particle deposition result. After setting the optimum condition, fine results with well deposited shape on whole area of the wafer and outstanding particle size uniformity of more than 70% were obtained. Although particle size shift phenomenon occurred in the measurement result using SP5 due to the intrinsic principle, SEM analysis demonstrated that particles with 60, 80 nm sized silica particles were well deposited on wafer. We believe the standard wafer made by our particle deposition system could be utilized and helpful for performance evaluation and development of wafer cleaning technologies.

In0.5Ga0.5N layers by Atomic Layer Deposition

We present an ALD approach to metastable In1-xGaxN with 0.1 < x < 0.5 based on solid In- and Ga-precursors that were co-sublimed into the deposition chamber in one pulse....

Dependence of Resistivity on Thickness of Vacuum Deposited Copper Thin Films

In depth understanding of resistivity of metals is of utmost importance for optimizing circuit designs and electrical systems. In this study, we investigated the relation between film thickness (in the range of 25−350 nm) and film resistivity of Cu thin films, with respect to thin film temperature sensors. The films were deposited in a vacuum deposition chamber over pyrex substrates and the film resistances were measured using 4 point probe technique. The empirical relationship established by Lacy has been used along with our experimental results in order to calculate the constants relating the filmsubstrate compatibility, which influences the change of resistivity with thickness.

Удельное электросопротивление тонких углеродных пленок с различной долей sp-связей

The technique of ion-plasma pulse-arc sputtering of graphite in a methane atmosphere has been employed to produce carbon films with different phase composition. Raman spectroscopy and transmission electron microscopy showed that increase of methane concentration in the vacuum deposition chamber leads to the growth of fraction containing sp-hybridized chains. In the investigated films structure, resistivity strongly correlates with the content of sp-hybridized carbon.