Nonthermal Microwave Plasma Synthesis of Crystalline Titanium Oxide & Titanium Nitride Nanoparticles

1991 ◽  
Vol 249 ◽  
Author(s):  
Prabhjot Mehta ◽  
A. K. Singh ◽  
A. I. Kingon

ABSTRACTWe report the nonthermal synthesis of ultrafine crystalline nanoparticles of titanium oxide and titanium nitride. The nanoparticles are formed by gas phase reactions between precursor gases dissociated in the microwave plasma. For the production of titanium nitride, titanium tetraisopropoxide (TTIP) and ammonia or nitrogen precursor gases are used. For titanium oxide production TTIP and oxygen are used as precursor gases. In both cases ultrahigh purity argon serves as a carrier gas and diluent.Transmission electron microscopy (TEM) revealed that the titanium nitride powders so formed were either cubic (TiN) or tetragonal (Ti2N) depending on the operational conditions, particularly the relative nitrogen gas flow rates. Ammonia gas was found to be a much more reactive nitrogen source than molecular nitrogen gas. For the titanium oxide growth an excess of oxygen was utilized to achieve TiO2. Powders collected from the gas phase corresponded to the rutile (tetragonal) phase. However, powders collected from the cavity walls corresponded to the high temperature and pressure (orthorhombic) 13-TiO2. There was also evidence of a polytypically modulated phase of TiO2, with the observed c-periodicity double the parent c-periodicity of the rutile phase. Using a low oxygen flow rate during powder formation led to the formation of orthorhombic Ti3O5 “powders”. The powders were easily sinterable by in situ electron beam annealing in the electron microscope, with an estimated temperature of around 550°C. This is much lower than the temperatures normally required to sinter these materials.

MRS Advances ◽  
2018 ◽  
Vol 3 (3) ◽  
pp. 165-170
Author(s):  
Shumpei Ogawa ◽  
Tatsuya Kuroda ◽  
Ryuga Koike ◽  
Hiroki Ishizaki

AbstractRecently, Plasma Assisted Atomic Layer Deposition Technique will easily control the thickness and the composition of semiconductor films. The radical generated by using the plasma techniques, gave the decrease of the defect into the semiconductor films. In this investigation, the relationship between microwave plasma power, nitrogen gas flow rate and concentration of generated nitrogen radical, was evaluated. At the first, Plasma emission spectrum at microwave plasma power (0 to 400W) was measured using a mixed 200sccm argon gas and 10sccm nitrogen gas. Next, the plasma emission spectrum was measured in the mixing of nitrogen gas flow rate (0 to 40sccm) with 200sccm argon gas flow rate. At that time, the microwave plasma power was set to 200W. Nitrogen radical spectrum were identified from all the emission spectrum, and the nitrogen radical intensity was calculated. As a result, the nitrogen radical intensity became the largest at 200sccm argon gas flow rate and 10sccm nitrogen gas flow rate. In addition, the nitrogen radical intensity increased in proportion to the microwave plasma power. The concentration of generated nitrogen radical could be controlled by changing the microwave plasma power and the nitrogen gas flow rate. Mentioned above, nitride thin films will be obtained on Si Substrates by microwave generated remote plasma assisted atomic layer deposition technique.


1992 ◽  
Vol 7 (4) ◽  
pp. 888-893 ◽  
Author(s):  
M. Sherif El-Eskandarany ◽  
K. Sumiyama ◽  
K. Aoki ◽  
K. Suzuki

Nonequilibrium titanium-nitride alloy powders have been fabricated by a high energetic ball mill under nitrogen gas flow at room temperature and characterized by means of x-ray diffraction, scanning electron microscopy, transmission electron microscopy, and differential scanning calorimetry. Initial hcp titanium is completely transformed to nonequilibrium-fcc Ti–N after 720 ks of the milling time. The fcc Ti–N phase is stable at relatively low temperature and transforms at 855 K to Ti2N and δ phases. At the final stage of milling, the particle- and grain-sizes of alloy powders are 1 mm and 5 nm, respectively, and the lattice parameter is 0.419 nm.


1997 ◽  
Vol 482 ◽  
Author(s):  
Jeffrey S. Dycka ◽  
Kathleen Kash ◽  
Kwiseon Kim ◽  
Walter R. L Lambrecht ◽  
Cliff C. Hayman ◽  
...  

AbstractPolycrystalline, wurtzitic indium nitride was synthesized by saturating indium metal with atomic nitrogen from a microwave plasma source. Plasma synthesis avoids the high equilibrium pressures required when molecular nitrogen is used as the nitrogen source. Two types of growth were observed: 1) small amounts of indium nitride crystallized from the melt during cooling and 2) hexagonal platelets formed adjacent to the In metal source on the crucible sides. The mechanism of this latter growth is not established, but may involve transport of indium as a liquid film. The crystals were characterized by electron diffraction, X-ray diffraction, elemental analysis, scanning electron microscopy, and Raman spectroscopy. Lattice parameter and Raman active phonon modes are reported and compared with calculations based on the full-potential linear muffin-tin orbital method (FP-LMTO).


Author(s):  
O. A. Kabov ◽  
V. V. Kuznetsov ◽  
J. C. Legros

The conjugated two-dimensional model, based on long-wave theory, of a steady laminar flow of liquid film and co-current gas flow in plane channel with the height varied from 150 to 500 μm is performed. A chip with the several millimeters length is located on the bottom wall of channel. The linearised approximation of the problem is obtained analytically. Numerical calculations are executed for liquid FC-72 and Nitrogen gas flow. In contrast to a case of a large channel, there is essential an influence of liquid film deformations on pressure and velocity in a gas phase.


1998 ◽  
Vol 6 (3) ◽  
pp. 143 ◽  
Author(s):  
P. D. Milewski ◽  
S. K. Streiffer ◽  
A. I. Kingon ◽  
I. K. Shmagin ◽  
R. M. Kolbas ◽  
...  

2016 ◽  
Vol 26 (2) ◽  
pp. 157-159 ◽  
Author(s):  
Ning Luo ◽  
Hong Wen Jing ◽  
Zhan Guo Ma ◽  
Weidong Liu ◽  
Liangchi Zhang ◽  
...  

2011 ◽  
Vol 206 (6) ◽  
pp. 1449-1453 ◽  
Author(s):  
Shouichiro Iio ◽  
Kosuke Yanagisawa ◽  
Chizuru Uchiyama ◽  
Katsuya Teshima ◽  
Naomichi Ezumi ◽  
...  

1999 ◽  
Vol 572 ◽  
Author(s):  
Jingxi Sun ◽  
J. M. Redwing ◽  
T. F. Kuech

ABSTRACTA comparative study of two different MOVPE reactors used for GaN growth is presented. Computational fluid dynamics (CFD) was used to determine common gas phase and fluid flow behaviors within these reactors. This paper focuses on the common thermal fluid features of these two MOVPE reactors with different geometries and operating pressures that can grow device-quality GaN-based materials. Our study clearly shows that several growth conditions must be achieved in order to grow high quality GaN materials. The high-temperature gas flow zone must be limited to a very thin flow sheet above the susceptor, while the bulk gas phase temperature must be very low to prevent extensive pre-deposition reactions. These conditions lead to higher growth rates and improved material quality. A certain range of gas flow velocity inside the high-temperature gas flow zone is also required in order to minimize the residence time and improve the growth uniformity. These conditions can be achieved by the use of either a novel reactor structure such as a two-flow approach or by specific flow conditions. The quantitative ranges of flow velocities, gas phase temperature, and residence time required in these reactors to achieve high quality material and uniform growth are given.


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