Preparation and Microwave Permittivity of Nano-Sized Si/C/N Powder

2005 ◽  
Vol 475-479 ◽  
pp. 3571-3574 ◽  
Author(s):  
Xiao Kui Liu ◽  
Wan Cheng Zhou ◽  
Fa Luo ◽  
Dong Mei Zhu
Keyword(s):  
Nitrogen Content ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Dissipation Factor ◽  
Nano Powder ◽  
Heat Treated ◽  
Different Temperatures ◽  
Degree Of Crystallization ◽  
Microwave Permittivity ◽  
N Powder

Nano-sized Si/C/N powders are prepared from hexamethyldisilazane ((CH3)3Si)2NH) by chemical vapor deposition (CVD) at different pyrolysis temperatures from 900°C to 1200°C. The as-formed Si/C/N nano powder is amorphous, and after controlled heat-treatment, SiC crystals formed. The composition of the Si/C/N powders prepared at different conditions is analyzed and the result shows that the nitrogen content of the Si/C/N powder is related to the synthesizing temperature. Si/C/N powders heat-treated at different temperatures are mixed with paraffin wax and the microwave permittivity of the mixture is measured. The result shows that the e¢, e², and the dissipation factor tg d ( e²/ e¢) of the mixture are high at the frequency of 8.2~12.4GHz, and the nitrogen content and the degree of crystallization have influence on the microwave permittivity. We believe that the high value of e¢, e² ,and tg d are due to the dielectric relaxation as the result of nitrogen atoms doped in silicon carbide lattice.

Temperature-Induced Structure and Morphological Transformation in SnS Prepared by a Chemical Vapor Deposition Method

2014 ◽  
Vol 513-517 ◽  
pp. 286-290 ◽  
Author(s):  
Ren Fu Zhuo ◽  
Yi Nong Wang ◽  
De Yan ◽  
Xiao Yong Xu ◽  
Zhi Guo Wu
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Chemical Vapor Deposition Method ◽  
Morphological Transformation ◽  
Simple Chemical ◽  
Different Temperatures ◽  
Sns Thin Films ◽  
Induced Structure ◽  
Made In

SnS thin films were deposited at different temperatures on silicon and quartz plates through directly elementary reaction via a simple chemical vapor deposition (CVD) process. The as-prepared products have a transformation of morphology from plate-like to granule-like when the temperature increased. A mechanism involving two competitive factors, surface energy and binding energy, was proposed to understand their growth. The products prepared at low temperature were single crystal while the films made in high temperature are polycrystal, the optical band gap (1.2~2.1ev) and the Sn:S atom ratios increases as the deposited temperature increases.

scholarly journals Effect of Ammonia Activation and Chemical Vapor Deposition on the Physicochemical Structure of Activated Carbons for CO2 Adsorption

Processes ◽  
2019 ◽  
Vol 7 (11) ◽  
pp. 801
Author(s):  
Liu ◽  
Li ◽  
Dong ◽  
Li ◽  
Feng ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Pore Structure ◽  
Nitrogen Content ◽  
Vapor Deposition ◽  
Co2 Adsorption ◽  
Activated Carbons ◽  
Chemical Vapor ◽  
Physical Activation ◽  
Adsorption Performance ◽  
Physicochemical Structure

Focusing on the bottlenecks of traditional physical activation method for the preparation of activated carbons (ACs), we established a simple and scalable method to control the physicochemical structure of ACs and study their CO2 adsorption performance. The preparation is achieved by ammonia activation at different volume fractions of ammonia in the mixture (10%, 25%, 50%, 75%, and 100%) to introduce the nitrogen-containing functional groups and form the original pores and subsequent chemical vapor deposition (CVD) at different deposition times (30, 60, 90, and 120 min) to further adjust the pore structure. The nitrogen content of ACs-0.1/0.25/0.5/0.75/1 increases gradually from 2.11% to 8.84% with the increase of ammonia ratio in the mixture from 10% to 75% and then decreases to 3.02% in the process of pure ammonia activation (100%), during which the relative content of pyridinium nitrogen (N-6), pyrrolidine (N-5), and graphite nitrogen (N-Q) increase sequentially but nitrogen oxygen structure (N-O) increase continuously. In addition, ACs-0.5 and ACs-0.75, with a relatively high nitrogen content (6.37% and 8.84%) and SBET value (1048.65 m2/g and 814.36 m2/g), are selected as typical samples for subsequent CVD. In the stage of CVD, ACs-0.5-60 and ACs-0.75-90, with high SBET (1897.25 and 1971.57 m2/g) value and an appropriate pore-size distribution between 0.5 and 0.8 nm, can be obtained with the extension of deposition time from 60 to 90 min. The results of CO2 adsorption test indicate that an adsorption capacity of ACs-0.75-90, at 800 mmHg, is the largest (6.87 mmol/g) out of all the tested samples. In addition, the comparison of CO2 adsorption performance of tested samples with different nitrogen content and pore structure indicates that the effect of nitrogen content seems to be more pronounced in this work.

Effect of Deposition Temperature on Surface Roughness of Nanocrystalline Diamond Film

2012 ◽  
Vol 476-478 ◽  
pp. 2353-2356
Author(s):  
Wen Qi Dai ◽  
Lin Jun Wang ◽  
Jian Huang ◽  
Yi Feng Liu ◽  
Ke Tang ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Chemical Vapor Deposition ◽  
Diamond Film ◽  
Vapor Deposition ◽  
Deposition Temperature ◽  
Chemical Vapor ◽  
Nanocrystalline Diamond ◽  
Different Temperatures ◽  
Hot Filament

Nanocrystalline diamond (NCD) films were synthesized by hot-filament chemical vapor deposition (HFCVD) method at different temperatures (600 °C, 620°C, 640°C and 660°C). The AFM and Raman analyses demonstrated that deposition temperature has a great effect on the surface roughness and quality of NCD films and 620°C is the temperature to grow NCD films with smooth surfaces.

Thin Oxynitride Films Prepared by Low Pressure Rapid Thermal Chemical Vapor Deposition

1993 ◽  
Vol 303 ◽  
Author(s):  
P.K. Mclarty ◽  
W.L. Hill ◽  
X.L Xu ◽  
J.J. Wortman ◽  
G.S. Harris
Keyword(s):  
Chemical Vapor Deposition ◽  
Nitrogen Content ◽  
Flow Rate ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Low Pressure ◽  
Flow Rate Ratio ◽  
Thermal Chemical Vapor Deposition ◽  
Rate Ratios ◽  
Post Deposition

ABSTRACTThin silicon oxynitride (Si-O-N) films have been deposited using low pressure rapid thermal chemical vapor deposition (RTCVD) with silane (SiH4), nitrous oxide (N2O), and ammonia (NH3) as the reactive gases. Structural analysis coupled with a study of deposition conditions indicate that an increase in NH3/N2O flow rate ratios leads to an increased N/O atomic ratio and a decreased Si-O-N deposition rate. Thin film (55-75A) polySi/Si-N-O/Si capacitors and transistors were fabricated for NH3/N2O flow rate ratios from 20% to 100%. Some of the films were subjected to a post deposition anneal at 950°C for 15 seconds in both argon and oxygen. Capacitance voltage measurements indicate a mid-gap interface trap density of ≤ 6 × 1010 eV−1cm−2 for all the films independent of both nitrogen content and post deposition annealing conditions. The transconductance was studied as a function of NH3/N2O flow rate ratio and decreasing peak gm values but improved high field degradation was observed for increased nitrogen content. This is consistent with previous work on nitrided oxides and suggests that the films are under tensile stress. Hot carrier stress at maximum substrate current was performed with the Si-O-N films displaying larger threshold voltage shifts when compared to furnace SiO2 indicating the possible existence of hydrogen related traps.

Effects of Irradiation by Low Energy Nitrogen Ions on Carbon Nitride Thin Films

2002 ◽  
Vol 750 ◽  
Author(s):  
Yuka Nasu ◽  
Masami Aono ◽  
Shinichiro Aizawa ◽  
Nobuaki Kitazawa ◽  
Yoshihisa Watanabe
Keyword(s):  
Thin Films ◽  
Nitrogen Content ◽  
Vapor Deposition ◽  
Photoelectron Spectroscopy ◽  
Carbon Nitride ◽  
Chemical Vapor ◽  
Low Energy ◽  
Carbon Filament ◽  
X Ray ◽  
Nitrogen Ions

ABSTRACTCarbon nitride (CNx) thin films have been prepared by hot carbon filament chemical vapor deposition, and the nitrogen content in the films is approximately 0.05. The CNx films have been irradiated by 0.1 keV nitrogen ions to increase the nitrogen content after deposition. The nitrogen content in the CNx films was obtained with X-ray photoelectron spectroscopy. Scanning electron microscopy was employed to study microstructures of the films. The experimental results show that nitrogen ions are chemically combined with the CNx films and as a result the nitrogen content increases up to approximately 0.30. Furthermore, it is found that nitrogen ions change the film microstructures and sputter the surfaces of CNx films.

Investigation of CsPbBr3 CVD dynamic at different temperatures

2021 ◽  
Author(s):  
Chenyang Bao ◽  
Xiang Peng ◽  
Yang Mei ◽  
Leiying Ying ◽  
Bao-Ping Zhang ◽  
...  
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Growth Dynamic ◽  
Different Temperatures

Since the emerging development of CsPbBr3 perovskite, chemical vapor deposition (CVD) became one of the most promising fabrication techniques to deposit precise, uniform perovskite thin films. However, the growth dynamic...

Reduction of p+-n+ Junction Tunneling Current for Base Current Improvement in Si/SiGe/Si Heterojunction Bipolar Transistors

1991 ◽  
Vol 220 ◽  
Author(s):  
Ž Matutinović-Krstelj ◽  
E. J. Prinz ◽  
P. V. Schwartz ◽  
J. C. Sturm
Keyword(s):  
Heterojunction Bipolar Transistors ◽  
Vapor Deposition ◽  
Tunneling Current ◽  
Chemical Vapor ◽  
Bipolar Transistors ◽  
Thermal Chemical Vapor Deposition ◽  
Base Current ◽  
Different Temperatures ◽  
High Reduction

ABSTRACTA reduction of parasitic tunneling current by three orders of magnitude in epitaxial p+-n+ junctions grown by Rapid Thermal Chemical Vapor Deposition (RTCVD) compared to previously published ion implantation results is reported. These results are very important for the reduction of base current in scaled homojunction and Si/SiGe/Si heterojunction bipolar transistors. High reduction in tunneling currents allows higher limits to transistor base and emitter dopings. Significant tunneling was observed when the doping levels at the lighter doped side of the junction were of the order of 1×1019cm−3 for both Si/Si and SiGe/Si devices. These results were confirmed by I-V measurements performed at different temperatures. Since the tunneling current is mediated by midgap states at the junction, these results demonstrate the high quality of the epitaxial interface.

The effect of oxygen in diamond deposition by microwave plasma enhanced chemical vapor deposition

1990 ◽  
Vol 5 (11) ◽  
pp. 2305-2312 ◽  
Author(s):  
Y. Liou ◽  
A. Inspektor ◽  
R. Weimer ◽  
D. Knight ◽  
R. Messier
Keyword(s):  
Chemical Vapor Deposition ◽  
High Temperatures ◽  
Vapor Deposition ◽  
Low Temperatures ◽  
Film Growth ◽  
Microwave Plasma ◽  
Chemical Vapor ◽  
Different Temperatures ◽  
Deposited Films

High quality diamond thin films were deposited on different substrates at temperatures from 300 to 1000 °C by the microwave plasma enhanced chemical vapor deposition (MPCVD) system. The quality of deposited diamond films was improved by adding oxygen in the gas mixtures. Different ratios of methane to oxygen concentration in hydrogen at different temperatures have been studied. At high temperatures (800–1000 °C), the addition of oxygen will not only enhance the growth rate of deposited films but also extend the region of diamond formation. At low temperatures (<500 °C), the oxygen plays an important role in diamond film growth by preferentially etching the non-diamond carbon. Without the addition of oxygen, the films deposited at high temperatures (>900 °C) were either graphitic or diamond containing a large amount of graphitic or amorphous carbon and at low temperatures (<500 °C) were white, soot-like coatings which were easily scraped off. The quality of the deposited films was characterized by Raman spectroscopy and scanning electron microscopy.

Sign in / Sign up

Export Citation Format

Share Document